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Outputs (196)

Comparison of Fourier optics-based methods for modeling coherence scanning interferometry (2024)
Journal Article
Hooshmand, H., Pahl, T., de Groot, P. J., Lehmann, P., Pappas, A., Su, R., …Piano, S. (2024). Comparison of Fourier optics-based methods for modeling coherence scanning interferometry. Optical Engineering, 63(04), https://doi.org/10.1117/1.oe.63.4.044102

Coherence scanning interferometry (CSI) is a widely used optical method for surface topography measurement of industrial and biomedical surfaces. The operation of CSI can be modeled using approximate physics-based approaches with minimal computationa... Read More about Comparison of Fourier optics-based methods for modeling coherence scanning interferometry.

Vision-based detection and coordinate metrology of a spatially encoded multi-sphere artefact (2023)
Journal Article
Isa, M. A., Leach, R., Branson, D., & Piano, S. (2024). Vision-based detection and coordinate metrology of a spatially encoded multi-sphere artefact. Optics and Lasers in Engineering, 172, Article 107885. https://doi.org/10.1016/j.optlaseng.2023.107885

New developments in vision algorithms prioritise identification and perception over accurate coordinate measurement due to the complex problem of resolving object form and pose from images. Consequently, many vision algorithms for coordinate measurem... Read More about Vision-based detection and coordinate metrology of a spatially encoded multi-sphere artefact.

Review of material measures for surface topography instrument calibration and performance verification (2023)
Journal Article
Pappas, A., Newton, L., Thompson, A., & Leach, R. (2024). Review of material measures for surface topography instrument calibration and performance verification. Measurement Science and Technology, 35(1), Article 012001. https://doi.org/10.1088/1361-6501/acf1b9

As the need for the manufacturing of complex surface topographies increases, traceable measurement with known uncertainties can allow a manufacturing process to remain stable. Material measures are the link in the chain that connects the surface topo... Read More about Review of material measures for surface topography instrument calibration and performance verification.

Virtual optical instrument for uncertainty evaluation in surface topography measurement (2023)
Presentation / Conference
Hooshmand, H., Pappas, A., Su, R., Leach, R., & Piano, S. (2023, September). Virtual optical instrument for uncertainty evaluation in surface topography measurement. Paper presented at 15th International Symposium on Measurement Technology and Intelligent Instruments (ISMTII 2023), Seoul, South Korea

Uncertainty evaluation for optical techniques measuring surfaces with complex topography is an open issue in industrial metrology. The ISO standard framework attempts to simplify calibration and uncertainty evaluation by introducing a fixed set of me... Read More about Virtual optical instrument for uncertainty evaluation in surface topography measurement.

Comparison of approximate methods for modelling coherence scanning interferometry (2023)
Journal Article
Hooshmand, H., Pahl, T., de Groot, P. J., Lehmann, P., Pappas, A., Su, R., …Piano, S. (2023). Comparison of approximate methods for modelling coherence scanning interferometry. Proceedings of SPIE, 12619, https://doi.org/10.1117/12.2673657

Coherence scanning interferometry (CSI) is a widely used optical method for surface topography measurement of industrial and biomedical surfaces. The operation of CSI can be modelled using approximate physics-based approaches with minimal computation... Read More about Comparison of approximate methods for modelling coherence scanning interferometry.

High-accuracy robotic metrology for precise industrial manipulation tasks (2023)
Conference Proceeding
Isa, M. A., Khanesar, M. A., Leach, R. K., Branson, D., & Piano, S. (2023). High-accuracy robotic metrology for precise industrial manipulation tasks. . https://doi.org/10.1117/12.2673088

The majority of industrial production processes can be divided into a series of object manipulation and handling tasks that can be adapted for robots. Through significant advances in compliant grasping, sensing and actuation technologies, robots are... Read More about High-accuracy robotic metrology for precise industrial manipulation tasks.

Comparison of coherence scanning interferometry, focus variation and confocal microscopy for surface topography measurement (2023)
Conference Proceeding
Hooshmand, H., Liu, M., Pappas, A., Thompson, A., Leach, R., & Piano, S. (2023). Comparison of coherence scanning interferometry, focus variation and confocal microscopy for surface topography measurement.

The most common optical technologies for surface topography measurement are coherence scanning interferometry (CSI), focus variation microscopy (FV) and imaging confocal microscopy (CM). Due to the benefits and drawbacks of each, these instruments ar... Read More about Comparison of coherence scanning interferometry, focus variation and confocal microscopy for surface topography measurement.

New Standard for Metal Powder Bed Fusion Surface Texture Measurement and Characterisation (2023)
Journal Article
Thompson, A., Newton, L., & Leach, R. (2023). New Standard for Metal Powder Bed Fusion Surface Texture Measurement and Characterisation. Metrology, 3(2), 237-245. https://doi.org/10.3390/metrology3020013

As metal additive manufacturing has been increasingly accepted as a viable method of industrial manufacture, there has been a significant uptake in manufacturers wishing to verify and test their parts through analysis of part surface. However, variou... Read More about New Standard for Metal Powder Bed Fusion Surface Texture Measurement and Characterisation.

A Neural Network Separation Approach for the Inclusion of Static Friction in Nonlinear Static Models of Industrial Robots (2023)
Journal Article
Ahmadieh Khanesar, M., Yan, M., Syam, W. P., Piano, S., Leach, R. K., & Branson, D. (2023). A Neural Network Separation Approach for the Inclusion of Static Friction in Nonlinear Static Models of Industrial Robots. IEEE/ASME Transactions on Mechatronics, 28(6), 3294-3304. https://doi.org/10.1109/TMECH.2023.3262644

Static friction modeling is a critical task to have the accurate robot model. In this article, a neural network separation approach to include nonlinear static friction in models of industrial robots is proposed. For this purpose, the terms correspon... Read More about A Neural Network Separation Approach for the Inclusion of Static Friction in Nonlinear Static Models of Industrial Robots.

Improving the localisation of features for the calibration of cameras using EfficientNets (2023)
Journal Article
Eastwood, J., Gayton, G., Leach, R. K., & Piano, S. (2023). Improving the localisation of features for the calibration of cameras using EfficientNets. Optics Express, 31(5), 7966-7982. https://doi.org/10.1364/OE.478934

Camera-based methods for optical coordinate metrology, such as digital fringe projection, rely on accurate calibration of the cameras in the system. Camera calibration is the process of determining the intrinsic and distortion parameters which define... Read More about Improving the localisation of features for the calibration of cameras using EfficientNets.

Quantitative investigation of the validity conditions for the Beckmann-Kirchhoff scattering model (2022)
Journal Article
Hooshmand, H., Liu, M., Leach, R., & Piano, S. (2022). Quantitative investigation of the validity conditions for the Beckmann-Kirchhoff scattering model. Optical Engineering, 61(12), Article 124113. https://doi.org/10.1117/1.OE.61.12.124113

Approximate and rigorous methods are widely used to model light scattering from a surface. The boundary element method (BEM) is a rigorous model that accounts for polarization and multiple scattering effects. BEM is suitable to model the scattered li... Read More about Quantitative investigation of the validity conditions for the Beckmann-Kirchhoff scattering model.

Autonomous image background removal for accurate and efficient close-range photogrammetry (2022)
Journal Article
Eastwood, J., Leach, R. K., & Piano, S. (2023). Autonomous image background removal for accurate and efficient close-range photogrammetry. Measurement Science and Technology, 34(3), Article 035404. https://doi.org/10.1088/1361-6501/aca497

Close-range photogrammetry can be used to reconstruct dense point clouds of an object with very high surface coverage, making it useful for manufacturing metrology tasks such as part inspection and validation. However, compared to competing technique... Read More about Autonomous image background removal for accurate and efficient close-range photogrammetry.

Evaluating parametric uncertainty using non-linear regression in fringe projection (2022)
Journal Article
Gayton, G., Isa, M., & Leach, R. K. (2023). Evaluating parametric uncertainty using non-linear regression in fringe projection. Optics and Lasers in Engineering, 162, Article 107377. https://doi.org/10.1016/j.optlaseng.2022.107377

Optical coordinate measurement systems, such as fringe projection systems, offer fast, high-density measurements of arbitrary surface topographies. The versatility, speed and information density of fringe projection measurements make them attractive... Read More about Evaluating parametric uncertainty using non-linear regression in fringe projection.

Applications of data fusion in optical coordinate metrology: a review (2022)
Journal Article
Zhang, Z. M., Catalucci, S., Thompson, A., Leach, R., & Piano, S. (2023). Applications of data fusion in optical coordinate metrology: a review. International Journal of Advanced Manufacturing Technology, 124, 1341-1356. https://doi.org/10.1007/s00170-022-10576-7

Data fusion enables the characterisation of an object using multiple datasets collected by various sensors. To improve optical coordinate measurement using data fusion, researchers have proposed numerous algorithmic solutions and methods. The most po... Read More about Applications of data fusion in optical coordinate metrology: a review.

Quantifying the validity conditions of the Beckmann-Kirchhoff scattering model (2022)
Conference Proceeding
Hooshmand, H., Liu, M., Leach, R., & Piano, S. (2022). Quantifying the validity conditions of the Beckmann-Kirchhoff scattering model. In D. Kim, H. Choi, & H. Ottevaere (Eds.), Proc. SPIE 12221, Optical Manufacturing and Testing XIV. https://doi.org/10.1117/12.2639003

Approximate and rigorous methods are widely used to model light scattering from a surface. The boundary element method (BEM) is a rigorous model that accounts for polarisation and multiple scattering effects. BEM is suitable to model the scattered li... Read More about Quantifying the validity conditions of the Beckmann-Kirchhoff scattering model.

Smart optical coordinate and surface metrology (2022)
Journal Article
Catalucci, S., Thompson, A., Eastwood, J., Zhang, Z. M., Branson, D. T., Leach, R., & Piano, S. (2022). Smart optical coordinate and surface metrology. Measurement Science and Technology, 34(1), Article 012001. https://doi.org/10.1088/1361-6501/ac9544

Manufacturing has recently experienced increased adoption of optimised and fast solutions for checking product quality during fabrication, allowing for manufacturing times and costs to be significantly reduced. Due to the integration of machine learn... Read More about Smart optical coordinate and surface metrology.

Optical system for the measurement of the surface topography of additively manufactured parts (2022)
Journal Article
Vilar, N., Artigas, R., Bermudez, C., Thompson, A., Newton, L., Leach, R., …Carles, G. (2022). Optical system for the measurement of the surface topography of additively manufactured parts. Measurement Science and Technology, 33(10), Article 104001. https://doi.org/10.1088/1361-6501/ac7c5c

Additive manufacturing (AM) is now regularly used for customised fabrication of parts with complex shapes and geometries. However, the large range of relevant scales, high slopes, step-like transitions, undercuts, alternation between dark and overly... Read More about Optical system for the measurement of the surface topography of additively manufactured parts.

Frequency scanning interferometry for accurate robot position measurement (2022)
Conference Proceeding
Isa, M. A., Khanesar, M. A., Leach, R., Branson, D., & Piano, S. (2022). Frequency scanning interferometry for accurate robot position measurement. In Proceedings of 22nd International Conference & Exhibition

This paper presents a frequency scanning interferometry (FSI) shortwave infrared (IR) setup developed for position and orientation measurement of industrial robots. Within contemporary and future industrial frameworks, robots—in particular collaborat... Read More about Frequency scanning interferometry for accurate robot position measurement.

Detailed Three-Dimensional Building Façade Reconstruction: A Review on Applications, Data and Technologies (2022)
Journal Article
Klimkowska, A., Cavazzi, S., Leach, R., & Grebby, S. (2022). Detailed Three-Dimensional Building Façade Reconstruction: A Review on Applications, Data and Technologies. Remote Sensing, 14(11), 2579. https://doi.org/10.3390/rs14112579

Urban environments are regions of complex and diverse architecture. Their reconstruction and representation as three-dimensional city models have attracted the attention of many researchers and industry specialists, as they increasingly recognise the... Read More about Detailed Three-Dimensional Building Façade Reconstruction: A Review on Applications, Data and Technologies.

Measurement of laser powder bed fusion surfaces with light scattering and unsupervised machine learning (2022)
Journal Article
Liu, M., Senin, N., Su, R., & Leach, R. (2022). Measurement of laser powder bed fusion surfaces with light scattering and unsupervised machine learning. Measurement Science and Technology, 33(7), Article 074006. https://doi.org/10.1088/1361-6501/ac6569

Quality monitoring for laser powder bed fusion (L-PBF), particularly in-process and real-time monitoring, is of importance for part quality assurance and manufacturing cost reduction. Measurement of layer surface topography is critical for quality mo... Read More about Measurement of laser powder bed fusion surfaces with light scattering and unsupervised machine learning.

Optical metrology for digital manufacturing: a review (2022)
Journal Article
Catalucci, S., Thompson, A., Piano, S., Branson, D. T., & Leach, R. (2022). Optical metrology for digital manufacturing: a review. International Journal of Advanced Manufacturing Technology, 120(7-8), 4271-4290. https://doi.org/10.1007/s00170-022-09084-5

With the increasing adoption of Industry 4.0, optical metrology has experienced a significant boom in its implementation, as an ever-increasing number of manufacturing processes are overhauled for in-process measurement and control. As such, optical... Read More about Optical metrology for digital manufacturing: a review.

Generation and categorisation of surface texture data using a modified progressively growing adversarial network (2021)
Journal Article
Eastwood, J., Newton, L., Leach, R., & Piano, S. (2022). Generation and categorisation of surface texture data using a modified progressively growing adversarial network. Precision Engineering, 74, 1-11. https://doi.org/10.1016/j.precisioneng.2021.10.020

As machine learning becomes more popular in the precision engineering sector, the need for large datasets of measurement data increases. Due to the often manual, user dependent and labour-intensive measurement processes, collecting a large amount of... Read More about Generation and categorisation of surface texture data using a modified progressively growing adversarial network.

Surface measuring coherence scanning interferometry beyond the specular reflection limit (2021)
Journal Article
Thomas, M., Su, R., de Groot, P., Coupland, J., & Leach, R. (2021). Surface measuring coherence scanning interferometry beyond the specular reflection limit. Optics Express, 29(22), 36121-36131. https://doi.org/10.1364/OE.435715

The capability of optical surface topography measurement methods for measurement of steep and tilted surfaces is investigated through modelling of a coherence scanning interferometer. Of particular interest is the effect on the interference signal an... Read More about Surface measuring coherence scanning interferometry beyond the specular reflection limit.

Development of a compact focus variation microscopy sensor for on-machine surface topography measurement (2021)
Journal Article
Santoso, T., Syam, W. P., Darukumalli, S., & Leach, R. (2022). Development of a compact focus variation microscopy sensor for on-machine surface topography measurement. Measurement, 187, Article 110311. https://doi.org/10.1016/j.measurement.2021.110311

On-machine areal surface topography measuring instruments are required for fast and accurate measurement of parts inside production machines without reducing production rates. This paper presents the design and development of a compact focus variatio... Read More about Development of a compact focus variation microscopy sensor for on-machine surface topography measurement.

Low thermal expansion machine frame designs using lattice structures (2021)
Journal Article
Juasiripukdee, P., Maskery, I., Ashcroft, I., & Leach, R. (2021). Low thermal expansion machine frame designs using lattice structures. Applied Sciences, 11(19), Article 9135. https://doi.org/10.3390/app11199135

In this work, we investigated tessellating cellular (or lattice) structures for use in a low thermal expansion machine frame. We proposed a concept for a lattice structure with tailorable effective coefficient of thermal expansion (CTE). The design i... Read More about Low thermal expansion machine frame designs using lattice structures.

Finite element modelling of defects in additively manufactured strut-based lattice structures (2021)
Journal Article
Echeta, I., Dutton, B., Leach, R. K., & Piano, S. (2021). Finite element modelling of defects in additively manufactured strut-based lattice structures. Additive Manufacturing, 47, Article 102301. https://doi.org/10.1016/j.addma.2021.102301

Strut-based lattice structures produced by powder bed fusion are prone to characteristic manufacturing defects that alter both their form and surface texture. Most studies in the literature focus on a subset of commonly observed defects, typically ra... Read More about Finite element modelling of defects in additively manufactured strut-based lattice structures.

Fourier optics modelling of coherence scanning interferometers (2021)
Conference Proceeding
de Groot, P. J., Colonna de Lega, X., Su, R., Coupland, J., & Leach, R. K. (2021). Fourier optics modelling of coherence scanning interferometers. In SPIE OPTICAL ENGINEERING + APPLICATIONS. https://doi.org/10.1117/12.2595668

We propose an instrument model for coherence scanning interferometry using familiar Fourier optics methods, the spectrum of plane waves, and the assumption that the light source spectral bandwidth is the dominant factor in determining fringe contrast... Read More about Fourier optics modelling of coherence scanning interferometers.

Efficient empirical determination of maximum permissible error in coordinate metrology (2021)
Journal Article
Thompson, A., Southon, N., Fern, F., Stupfler, G., & Leach, R. (2021). Efficient empirical determination of maximum permissible error in coordinate metrology. Measurement Science and Technology, 32(10), Article 105013. https://doi.org/10.1088/1361-6501/ac0c49

Maximum permissible errors (MPEs) are an important measurement system specification and form the basis of periodic verification of a measurement system's performance. However, there is no standard methodology for determining MPEs, so when they are no... Read More about Efficient empirical determination of maximum permissible error in coordinate metrology.

Evaluating and propagating uncertainty in digital fringe projection systems (2021)
Journal Article
Gayton, G., Isa, M., Su, R., & Leach, R. (2021). Evaluating and propagating uncertainty in digital fringe projection systems. Proceedings of SPIE, 11782, https://doi.org/10.1117/12.2592426

Fringe projection is a measurement technique able to produce high-density data measurements of Lambertian surfaces using a camera and projector. Evaluating the uncertainty of a fringe projection system is challenging because of the highdensity and th... Read More about Evaluating and propagating uncertainty in digital fringe projection systems.

Automated assessment of measurement quality in optical coordinate metrology of complex freeform parts (2021)
Conference Proceeding
Catalucci, S., Senin, N., Piano, S., & Leach, R. (2021). Automated assessment of measurement quality in optical coordinate metrology of complex freeform parts. In Conference Proceedings: 21st International Conference & Exhibition

The measurement of complex freeform geometries represents a fundamental challenge for quality assurance in the production of high value-added parts, in particular when additive manufacturing technologies are involved. In addition, the increasing adva... Read More about Automated assessment of measurement quality in optical coordinate metrology of complex freeform parts.

Physics-based virtual coherence scanning interferometer for surface measurement (2021)
Journal Article
Su, R., & Leach, R. (2021). Physics-based virtual coherence scanning interferometer for surface measurement. Light: Science and Applications, 2(2), 120-135. https://doi.org/10.37188/lam.2021.009

Virtual instruments provide task-specific uncertainty evaluation in surface and dimensional metrology. We demonstrate the first virtual coherence scanning interferometer that can accurately predict the results from measurements of surfaces with compl... Read More about Physics-based virtual coherence scanning interferometer for surface measurement.

Analysis of the tribological interaction of a polytetrafluoroethylene-lined radial lip oil seal, shaft and lubricant sample (2021)
Journal Article
Shabbir, S., Garvey, S. D., Dakka, S. M., Rothwell, B. C., Su, R., Leach, R., & Weston, N. (2022). Analysis of the tribological interaction of a polytetrafluoroethylene-lined radial lip oil seal, shaft and lubricant sample. Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology, 236(1), 123-143. https://doi.org/10.1177/13506501211005876

To investigate the tribological interaction and wear mechanisms of polytetrafluoroethylene-lined radial lip oil seals in service, a sleeve, seal and lubricant sample taken off a rotating rig are studied. The test was terminated at 72 h, after severe... Read More about Analysis of the tribological interaction of a polytetrafluoroethylene-lined radial lip oil seal, shaft and lubricant sample.

Evaluating the cytotoxicity of Ge–Sb–Se chalcogenide glass optical fibres on 3T3 mouse fibroblasts (2021)
Journal Article
Mabwa, D., Kubiena, T., Parnell, H., Su, R., Furniss, D., Tang, Z., …Seddon, A. B. (2021). Evaluating the cytotoxicity of Ge–Sb–Se chalcogenide glass optical fibres on 3T3 mouse fibroblasts. RSC Advances, 11(15), 8682-8693. https://doi.org/10.1039/d0ra00353k

In vivo cancer detection based on the mid-infrared molecular fingerprint of tissue is promising for the fast diagnosis and treatment of suspected cancer patients. Few materials are mid-infrared transmissive, even fewer, which can be converted into fu... Read More about Evaluating the cytotoxicity of Ge–Sb–Se chalcogenide glass optical fibres on 3T3 mouse fibroblasts.

Characterisation of a multi-view fringe projection system based on the stereo matching of rectified phase maps (2021)
Journal Article
Shaheen, A., Sims-Waterhouse, D., Bointon, P., Takushima, S., Piano, S., & Leach, R. K. (2021). Characterisation of a multi-view fringe projection system based on the stereo matching of rectified phase maps. Measurement Science and Technology, 32(4), Article 045006. https://doi.org/10.1088/1361-6501/abd445

Multi-view fringe projection systems can be effective solutions to address the limitations imposed by the limited field of view, line-of-sight issues and occlusions when measuring the geometry of complex objects, associated with single camera-projec... Read More about Characterisation of a multi-view fringe projection system based on the stereo matching of rectified phase maps.

Statistical point cloud model to investigate measurement uncertainty in coordinate metrology (2021)
Journal Article
Senin, N., Catalucci, S., Moretti, M., & Leach, R. (2021). Statistical point cloud model to investigate measurement uncertainty in coordinate metrology. Precision Engineering, 70, 44-62. https://doi.org/10.1016/j.precisioneng.2021.01.008

In this work an approach to investigate measurement uncertainty in coordinate metrology is presented, based on fitting Gaussian random fields to high-density point clouds produced by measurement repeats. The fitted field delivers a depiction of the s... Read More about Statistical point cloud model to investigate measurement uncertainty in coordinate metrology.

Laser triangulation (2020)
Book Chapter
Isa, M. A., Piano, S., & Leach, R. Laser triangulation. In R. Leach (Ed.), Advances in Optical Form and Coordinate Metrology. IOP Publishing. https://doi.org/10.1088/978-0-7503-2524-0ch3

This chapter gives a summary of laser triangulation as a measurement technique and outlines recent applications and challenges.

Real-time target alignment system for high-power high-repetition rate laser operations using a five degree-of-freedom hybrid mechanism (2020)
Journal Article
Karim, S., Piano, S., Branson, D., Santoso, T., Leach, R., & Tolley, M. (2022). Real-time target alignment system for high-power high-repetition rate laser operations using a five degree-of-freedom hybrid mechanism. International Journal of Control, 95(4), 867-885. https://doi.org/10.1080/00207179.2020.1827297

This paper presents a real-time position control solution for the targets used in the high-repetition rate laser operations of large-scale high-power laser facilities. The design of the control system is based on an Abbe-compliant, in-process positio... Read More about Real-time target alignment system for high-power high-repetition rate laser operations using a five degree-of-freedom hybrid mechanism.

Mathematical approach to the validation of surface texture filtration software (2020)
Journal Article
Todhunter, L., Leach, R., & Blateyron, F. (2020). Mathematical approach to the validation of surface texture filtration software. Surface Topography: Metrology and Properties, 8(4), Article 045017. https://doi.org/10.1088/2051-672X/abc0fb

A novel method for the validation of surface texture filtration software is introduced. Mathematically traceable reference pairs for linear Gaussian filtration are developed, utilising Fourier series surface definitions in conjunction with the freque... Read More about Mathematical approach to the validation of surface texture filtration software.

Mathematical approach to the validation of form removal surface texture software (2020)
Journal Article
Todhunter, L., Leach, R., & Blateyron, F. (2020). Mathematical approach to the validation of form removal surface texture software. Surface Topography: Metrology and Properties, 8(4), Article 045019. https://doi.org/10.1088/2051-672x/abc737

A new approach to the validation of surface texture form removal methods is introduced. A linear algebra technique is presented that obtains total least squares (TLS) model fits for a continuous mathematical surface definition. This model is applicab... Read More about Mathematical approach to the validation of form removal surface texture software.

Optimisation of camera positions for optical coordinate measurement based on visible point analysis (2020)
Journal Article
Zhang, H., Eastwood, J., Isa, M., Sims-Waterhouse, D., Leach, R., & Piano, S. (2021). Optimisation of camera positions for optical coordinate measurement based on visible point analysis. Precision Engineering, 67, 178-188. https://doi.org/10.1016/j.precisioneng.2020.09.016

In optical coordinate measurement using cameras, the number of images, and positions and orientations of the cameras, are critical to object accessibility and the accuracy of a measurement. In this paper, we propose a technique to optimise the number... Read More about Optimisation of camera positions for optical coordinate measurement based on visible point analysis.

Surface-process correlation for an ink-jet printed transparent fluoroplastic (2020)
Journal Article
Gomez, C., Campanelli, C., Su, R., & Leach, R. (2020). Surface-process correlation for an ink-jet printed transparent fluoroplastic. Surface Topography: Metrology and Properties, 8(3), https://doi.org/10.1088/2051-672X/abac1c

Ink-jet printing is one of the key technologies in the field of defined polymer deposition. There is currently a lack of knowledge regarding how some fluoropolymers, in this case THV 221, can be ink-jet printed. A quantitative analysis of the micro-s... Read More about Surface-process correlation for an ink-jet printed transparent fluoroplastic.

Review of the influence of noise in X-ray computed tomography measurement uncertainty (2020)
Journal Article
Sánchez, Á. R., Thompson, A., Körner, L., Brierley, N., & Leach, R. (2020). Review of the influence of noise in X-ray computed tomography measurement uncertainty. Precision Engineering, https://doi.org/10.1016/j.precisioneng.2020.08.004

Different aspects of noise in X-ray computed tomography (XCT) for industrial purposes are examined. An overview of the most common noise metrics is given, together with a description of XCT noise influence quantities. We address the current state of... Read More about Review of the influence of noise in X-ray computed tomography measurement uncertainty.

Feature-based characterisation of Ti6Al4V electron beam powder bed fusion surfaces fabricated at different surface orientations (2020)
Journal Article
Newton, L., Senin, N., Chatzivagiannis, E., Smith, B., & Leach, R. (2020). Feature-based characterisation of Ti6Al4V electron beam powder bed fusion surfaces fabricated at different surface orientations. Additive Manufacturing, 35, https://doi.org/10.1016/j.addma.2020.101273

Due to the layer-based nature of the powder bed fusion (PBF) process, part surfaces oriented in space at varying angles with respect to the build direction are differently affected by a wide array of manufacturing-induced phenomena (staircase effects... Read More about Feature-based characterisation of Ti6Al4V electron beam powder bed fusion surfaces fabricated at different surface orientations.

Ceria-coated replicated aluminium sponges as catalysts for the CO-water gas shift process (2020)
Journal Article
Palma, V., Goodall, R., Thompson, A., Ruocco, C., Renda, S., Leach, R., & Martino, M. (2021). Ceria-coated replicated aluminium sponges as catalysts for the CO-water gas shift process. International Journal of Hydrogen Energy, 46(22), 12158-12168. https://doi.org/10.1016/j.ijhydene.2020.04.065

A study on the use of chemical conversion coating as a preparative technique for foam-based structured catalysts, in the water gas shift reaction, is presented. The results showed a significant correlation between the textural properties of the struc... Read More about Ceria-coated replicated aluminium sponges as catalysts for the CO-water gas shift process.

Volumetric error modelling of a stereo vision system for error correction in photogrammetric three-dimensional coordinate metrology (2020)
Journal Article
Isa, M. A., Sims-Waterhouse, D., Piano, S., & Leach, R. (2020). Volumetric error modelling of a stereo vision system for error correction in photogrammetric three-dimensional coordinate metrology. Precision Engineering, 64, 188-199. https://doi.org/10.1016/j.precisioneng.2020.04.010

Optical three-dimensional coordinate measurement using stereo vision has systematic errors that affect measurement quality. This paper presents a scheme for measuring, modelling and correcting these errors. The position and orientation of a linear st... Read More about Volumetric error modelling of a stereo vision system for error correction in photogrammetric three-dimensional coordinate metrology.

Cascaded machine learning model for reconstruction of surface topography from light scattering (2020)
Journal Article
Liu, M., Senin, N., Su, R., & Leach, R. (2020). Cascaded machine learning model for reconstruction of surface topography from light scattering. Proceedings of SPIE, 11352, https://doi.org/10.1117/12.2555035

Light scattering methods are promising for in-process surface measurement. Many researchers have investigated light scattering methods for evaluating surface texture. Researchers working on scatterometry have developed methods to derive surface textu... Read More about Cascaded machine learning model for reconstruction of surface topography from light scattering.

Real-time target alignment system for high-power high-repetition rate laser operations using a five degree-of-freedom hybrid mechanism (2020)
Journal Article
Leach, R., Branson, D., Karim, S., Tolley, M., Piano, S., & Santoso, T. (2020). Real-time target alignment system for high-power high-repetition rate laser operations using a five degree-of-freedom hybrid mechanism. International Journal of Control, 95(4), 867-885. https://doi.org/10.1080/00207179.2020.1827297

This paper presents a real-time position control solution for the targets used in the high-repetition rate laser operations of high-power laser facilities. The control system is designed based on an Abbe-compliant, in-process position measurement sys... Read More about Real-time target alignment system for high-power high-repetition rate laser operations using a five degree-of-freedom hybrid mechanism.

Optical topography measurement of steeply-sloped surfaces beyond the specular numerical aperture limit (2020)
Journal Article
Thomas, M., Su, R., de Groot, P., & Leach, R. (2020). Optical topography measurement of steeply-sloped surfaces beyond the specular numerical aperture limit. Proceedings of SPIE, 11352, Article 1135207. https://doi.org/10.1117/12.2554568

Engineered functional surfaces often feature varying slopes on macro- and micro-scales. When surfaces are mirror-like, the highest surface slope that can be measured by a far-field 3D imaging optical surface measuring instrument is the arcsine of the... Read More about Optical topography measurement of steeply-sloped surfaces beyond the specular numerical aperture limit.

Metrological characteristics for the calibration of surface topography measuring instruments: a review (2020)
Journal Article
Leach, R. K., Haitjema, H., Su, R., & Thompson, A. (2020). Metrological characteristics for the calibration of surface topography measuring instruments: a review. Measurement Science and Technology, 32(3), https://doi.org/10.1088/1361-6501/abb54f

In this paper, we will review the development and use of an ISO standardised framework to allow calibration of surface topography measuring instruments. We will draw on previous work to present the state of the art in the field in terms of employed m... Read More about Metrological characteristics for the calibration of surface topography measuring instruments: a review.

Modeling of interference microscopy beyond the linear regime (2020)
Journal Article
Thomas, M., Su, R., Nikolaev, N., Coupland, J., & Leach, R. (2020). Modeling of interference microscopy beyond the linear regime. Optical Engineering, 59(3), https://doi.org/10.1117/1.oe.59.3.034110

Coherence scanning interferometry (CSI), a type of interference microscopy, has found broad applications in advanced manufacturing industry providing high-accuracy surface topography measurement. Enhancement of the metrological capability of CSI for... Read More about Modeling of interference microscopy beyond the linear regime.

Noise reduction in coherence scanning interferometry for surface topography measurement (2020)
Journal Article
Gomez, C., Su, R., De Groot, P., & Leach, R. (2020). Noise reduction in coherence scanning interferometry for surface topography measurement. Nanomanufacturing and Metrology, 3, 68–76. https://doi.org/10.1007/s41871-020-00057-4

Coherence scanning interferometry is one of the most accurate surface measuring technology, and it is increasingly applied to challenging surface structures, such as additive manufactured part and transparent films, directly in environments that rese... Read More about Noise reduction in coherence scanning interferometry for surface topography measurement.

Mathematical approach to the validation of field surface texture parameter software (2020)
Journal Article
Todhunter, L., Leach, R., Lawes, S., Harris, P., & Blateyron, F. (2020). Mathematical approach to the validation of field surface texture parameter software. Surface Topography: Metrology and Properties, 8(1), Article 015010. https://doi.org/10.1088/2051-672x/ab7367

A new method for performance validation of surface texture parameter calculation software is introduced, focussing on field surface texture parameters. Surface height functions are defined mathematically, either using Fourier series or polynomials, a... Read More about Mathematical approach to the validation of field surface texture parameter software.

Polymer powder bed fusion surface texture measurement (2020)
Journal Article
de Pastre, M., Thompson, A., Quinsat, Y., Albajez, J. A., Senin, N., & Leach, R. K. (2020). Polymer powder bed fusion surface texture measurement. Measurement Science and Technology, 31(5), https://doi.org/10.1088/1361-6501/ab63b1

Polymer laser powder bed fusion (LPBF) surfaces can be challenging to measure. These surfaces comprise complex features including undercuts, deep recesses, step-like transitions, a large range of measurement scales and unfavourable optically material... Read More about Polymer powder bed fusion surface texture measurement.

Lens aberration compensation in interference microscopy (2020)
Journal Article
Su, R., Thomas, M., Liu, M., Drs, J., Bellouard, Y., Pruss, C., …Leach, R. (2020). Lens aberration compensation in interference microscopy. Optics and Lasers in Engineering, 128, Article 106015. https://doi.org/10.1016/j.optlaseng.2020.106015

Emergence of products that feature functional surfaces with complex geometries, such as freeform optics in consumer electronics and augmented reality and virtual reality, requires high-accuracy non-contact surface measurement. However, large discrepa... Read More about Lens aberration compensation in interference microscopy.

Performance Verification of a Flexible Vibration Monitoring System (2020)
Journal Article
Bointon, P., Todhunter, L., Clare, A., & Leach, R. (2020). Performance Verification of a Flexible Vibration Monitoring System. Machines, 8(1), 3. https://doi.org/10.3390/machines8010003

The performance of measurement or manufacturing systems in high-precision applications is dependent upon the dynamics of the system, as vibration can be a significant contributor to the measurement uncertainty and process variability. Technologies ma... Read More about Performance Verification of a Flexible Vibration Monitoring System.

Review of defects in lattice structures manufactured by powder bed fusion (2019)
Journal Article
Echeta, I., Dutton, B., Feng, X., Leach, R., & Piano, S. (2020). Review of defects in lattice structures manufactured by powder bed fusion. International Journal of Advanced Manufacturing Technology, 106(5-6), 2649–2668. https://doi.org/10.1007/s00170-019-04753-4

Additively manufactured lattice structures are popular due to their desirable properties, such as high specific stiffness and high surface area, and are being explored for several applications including aerospace components, heat exchangers and biome... Read More about Review of defects in lattice structures manufactured by powder bed fusion.

Uncertainty model for a traceable stereo-photogrammetry system (2019)
Journal Article
Sims-Waterhouse, D., Isa, M., Piano, S., & Leach, R. (2020). Uncertainty model for a traceable stereo-photogrammetry system. Precision Engineering, 63, 1-9. https://doi.org/10.1016/j.precisioneng.2019.12.008

Through the computational modelling and experimental verification of a stereo-photogrammetry system, the expanded uncertainty on form measurement was estimated and was found to be , and for a 95% confidence interval (coverage factors of = 3.2, 2.0... Read More about Uncertainty model for a traceable stereo-photogrammetry system.

Design and characterisation of an additive manufacturing benchmarking artefact following a design-for-metrology approach (2019)
Journal Article
Santos, V. M. R., Thompson, A., Sims-Waterhouse, D., Maskery, I., Woolliams, P., & Leach, R. (2020). Design and characterisation of an additive manufacturing benchmarking artefact following a design-for-metrology approach. Additive Manufacturing, 32, Article 100964. https://doi.org/10.1016/j.addma.2019.100964

We present the design and characterisation of a high-speed sintering additive manufacturing benchmarking artefact following a design-for-metrology approach. In an important improvement over conventional approaches, the specifications and operating pr... Read More about Design and characterisation of an additive manufacturing benchmarking artefact following a design-for-metrology approach.

Comparison and validation of surface topography segmentation methods for feature-based characterisation of metal powder bed fusion surfaces (2019)
Journal Article
Newton, L., Senin, N., Smith, B., Chatzivagiannis, E., & Leach, R. (2019). Comparison and validation of surface topography segmentation methods for feature-based characterisation of metal powder bed fusion surfaces. Surface Topography: Metrology and Properties, 7(4), https://doi.org/10.1088/2051-672X/ab520a

Feature-based characterisation, i.e. the characterisation of surface topography based on the isolation of relevant topographic formations (features) and their dimensional assessment, is a developing field of surface texture metrology. Feature-based a... Read More about Comparison and validation of surface topography segmentation methods for feature-based characterisation of metal powder bed fusion surfaces.

Automated characterisation of multi-view fringe projection system for three- dimensional measurement of additively manufactured parts (2019)
Conference Proceeding
Leach, R. K., Shaheen, A., Piano, S., Sims-Waterhouse, D., & Bointon, P. (2019). Automated characterisation of multi-view fringe projection system for three- dimensional measurement of additively manufactured parts

Digital fringe projection is a non-contact method that is widely used for the dimensional characterisation of complex manufactured parts. However, single camera-projector fringe projection systems struggle to acquire the full three-dimensional point... Read More about Automated characterisation of multi-view fringe projection system for three- dimensional measurement of additively manufactured parts.

Comparison of two noise reduction methods in coherence scanning interferometry for surface measurement (2019)
Conference Proceeding
Gomez, C., Su, R., Lawes, S., & Leach, R. (2019). Comparison of two noise reduction methods in coherence scanning interferometry for surface measurement

Coherence scanning interferometry (CSI) can measure relatively flat surfaces with sub-nanometre precision, but the measurement noise may increase significantly if the intensity of the interferometric signal reduces when measuring non-flat surfaces or... Read More about Comparison of two noise reduction methods in coherence scanning interferometry for surface measurement.

Modelling Fringe Projection Based on Linear Systems Theory and Geometric Transformation (2019)
Conference Proceeding
Gayton, G., Su, R., & Leach, R. (2019). Modelling Fringe Projection Based on Linear Systems Theory and Geometric Transformation

Fringe projection measurement techniques offer fast, non-contact measurements of the surface form of manufactured parts at relatively low cost. Recent advances in fringe projection have reduced measurement errors from effects such as multiple surface... Read More about Modelling Fringe Projection Based on Linear Systems Theory and Geometric Transformation.

High-accuracy surface measurement through modelling of the surface transfer function in interference microscopy (2019)
Journal Article
Su, R., Thomas, M., Liu, M., Coupland, J., & Leach, R. (2019). High-accuracy surface measurement through modelling of the surface transfer function in interference microscopy. Proceedings of SPIE, 11102, Article 1110205. https://doi.org/10.1117/12.2528911

Surfaces featuring complex topographies, such as high slope angles, large curvatures and high aspect-ratio structures on both macro- and micro-scales, present significant challenges to optical measuring instruments. Here we demonstrate a method to ch... Read More about High-accuracy surface measurement through modelling of the surface transfer function in interference microscopy.

Does interferometry work? A critical look at the foundations of interferometric surface topography measurement (2019)
Journal Article
de Groot, P. J., Colonna de Lega, X., Su, R., & Leach, R. K. (2019). Does interferometry work? A critical look at the foundations of interferometric surface topography measurement. Proceedings of SPIE, 11102, Article 111020G. https://doi.org/10.1117/12.2526654

© 2019 SPIE. Interferometers for the measurement of surface form and texture have a reputation for high performance. However, the results for many types of surface features can deviate from the expectation of one cycle of phase shift per half wavelen... Read More about Does interferometry work? A critical look at the foundations of interferometric surface topography measurement.

Three-dimensional resonating metamaterials for low-frequency vibration attenuation (2019)
Journal Article
Elmadih, W., Chronopoulos, D., Syam, W., Maskery, I., Meng, H., & Leach, R. (2019). Three-dimensional resonating metamaterials for low-frequency vibration attenuation. Scientific Reports, 9(1), Article 11503. https://doi.org/10.1038/s41598-019-47644-0

Recent advances in additive manufacturing have enabled fabrication of phononic crystals and metamaterials which exhibit spectral gaps, or stopbands, in which the propagation of elastic waves is prohibited by Bragg scattering or local resonance effect... Read More about Three-dimensional resonating metamaterials for low-frequency vibration attenuation.

Increasing throughput in x-ray computed tomography measurement of surface topography using sinogram interpolation (2019)
Journal Article
Körner, L., Lawes, S., Bate, D., Newton, L., Senin, N., & Leach, R. K. (2019). Increasing throughput in x-ray computed tomography measurement of surface topography using sinogram interpolation. Measurement Science and Technology, 30(12), Article 125002. https://doi.org/10.1088/1361-6501/ab37e5

© 2019 Crown copyright. Reproduced with the permission of the Controller of Her Majesty's Stationery Office. X-ray computed tomography (XCT) is a non-destructive imaging technique that has recently gained interest as a tool to measure surface topogra... Read More about Increasing throughput in x-ray computed tomography measurement of surface topography using sinogram interpolation.

Uncertainty evaluation of fringe projection based on the linear systems theory (2019)
Conference Proceeding
Gayton, G., Su, R., Leach, R., & Bradley, L. (2019). Uncertainty evaluation of fringe projection based on the linear systems theory

Fringe projection techniques offer fast, non-contact measurements of the surface form of manufactured parts. Fringe projection has seen successful implementation in the automotive, aerospace and medical industries. Recently, advances in fringe projec... Read More about Uncertainty evaluation of fringe projection based on the linear systems theory.

Characterisation Of The Surface Topography Evolution Of An Ink-jet Printed Transparent Fluoroplastic With CSI (2019)
Presentation / Conference
Gomez, C., Campanelli, C., Su, R., Lawes, S., & Leach, R. (2019, July). Characterisation Of The Surface Topography Evolution Of An Ink-jet Printed Transparent Fluoroplastic With CSI. Poster presented at 22nd International Conference on Metrology & Properties of Surfaces, Lyon, France

We present the results of an empirical investigation into the evolution of the morphology of an ink jet printed trans parent polymer using coherence scanning interferometry (CSI). CSI is a high precision optical surface measuring technique, which ha... Read More about Characterisation Of The Surface Topography Evolution Of An Ink-jet Printed Transparent Fluoroplastic With CSI.

Modelling of coherence scanning interferometry for complex surfaces based on a boundary element method (2019)
Journal Article
Thomas, M., Su, R., Nikolaev, N., Coupland, J., & Leach, R. (2019). Modelling of coherence scanning interferometry for complex surfaces based on a boundary element method. Proceedings of SPIE, 11057, 1-12. https://doi.org/10.1117/12.2526015

Coherence scanning interferometry (CSI) is a well-established technique for measuring surface topography based on the coherence envelope and phase of interference fringes. The most commonly used surface reconstruction methods, i.e. frequency domain a... Read More about Modelling of coherence scanning interferometry for complex surfaces based on a boundary element method.

Multidimensional Phononic Bandgaps in Three-Dimensional Lattices for Additive Manufacturing (2019)
Journal Article
Elmadih, W., Syam, W. P., Maskery, I., Chronopoulos, D., & Leach, R. (2019). Multidimensional Phononic Bandgaps in Three-Dimensional Lattices for Additive Manufacturing. Materials, 12(11), Article 1878. https://doi.org/10.3390/ma12111878

We report on numerical modelling of three-dimensional lattice structures designed to provide phononic bandgaps. The examined lattice structures rely on two distinct mechanisms for bandgap formation: the destructive interference of elastic waves and i... Read More about Multidimensional Phononic Bandgaps in Three-Dimensional Lattices for Additive Manufacturing.

Automated assessment of object coverage in smart, optical form measurement (2019)
Conference Proceeding
Catalucci, S., Senin, N., Stavroulakis, P., & Leach, R. (2019). Automated assessment of object coverage in smart, optical form measurement. In Proceedings of 19th International euspen Conference & Exhibition

As part of a project to develop a smart 3D form measurement system for quality control of complex 3D parts, we present early work in algorithmic assessment of coverage achieved on the surfaces of a part subjected to optical measurement from a single... Read More about Automated assessment of object coverage in smart, optical form measurement.

Material standards design for minimum zone fitting of freeform optics (2019)
Presentation / Conference
Arezki, Y., Lepretre, F., Psota, P., Su, R., Heikkinen, V., Zhang, X., …Nouira, H. (2019, June). Material standards design for minimum zone fitting of freeform optics. Paper presented at euspen’s 19th International Conference & Exhibition, Bilbao, Spain

Optical measurement of surface topographies with transparent coatings (2019)
Journal Article
Feng, X., Senin, N., Su, R., Ramasamy, S., & Leach, R. (2019). Optical measurement of surface topographies with transparent coatings. Optics and Lasers in Engineering, 121, 261-270. https://doi.org/10.1016/j.optlaseng.2019.04.018

Manufacturers nowadays have access to state-of-the-art areal surface topography measurement instruments that allow investigation of surface topography at unprecedented levels of detail and over a wide range of scales. However, high value-added produc... Read More about Optical measurement of surface topographies with transparent coatings.

Methodology for the development of in-line optical surface measuring instruments with a case study for additive surface finishing (2019)
Journal Article
Syam, W. P., Rybalcenko, K., Gaio, A., Crabtree, J., & Leach, R. K. (2019). Methodology for the development of in-line optical surface measuring instruments with a case study for additive surface finishing. Optics and Lasers in Engineering, 121, 271-288. https://doi.org/10.1016/j.optlaseng.2019.04.015

The productivity rate of a manufacturing process is limited by the speed of any measurement processes at the quality control stage. Fast and effective in-line measurements are required to overcome this limitation. Optical instruments are the most pro... Read More about Methodology for the development of in-line optical surface measuring instruments with a case study for additive surface finishing.

Lateral error compensation for stitching-free measurement with focus variation microscopy (2019)
Journal Article
Pérez, P., Syam, W. P., Antonio Albajez, J., Santolaria, J., & Leach, R. (2019). Lateral error compensation for stitching-free measurement with focus variation microscopy. Measurement Science and Technology, 30(6), Article 065002. https://doi.org/10.1088/1361-6501/ab046e

This paper proposes a practical methodology to quantify and compensate lateral errors for focus variation microscopy measurements without stitching. The main advantages of this new methodology are its fast and simple implementation using any uncalibr... Read More about Lateral error compensation for stitching-free measurement with focus variation microscopy.

Towards superresolution surface metrology: quantum estimation of angular and axial separations (2019)
Journal Article
Napoli, C., Piano, S., Leach, R., Adesso, G., & Tufarelli, T. (2019). Towards superresolution surface metrology: quantum estimation of angular and axial separations. Physical Review Letters, 122(14), Article 140505. https://doi.org/10.1103/physrevlett.122.140505

We investigate the localization of two incoherent point sources with arbitrary angular and axial separations in the paraxial approximation. By using quantum metrology techniques, we show that a simultaneous estimation of the two separations is achiev... Read More about Towards superresolution surface metrology: quantum estimation of angular and axial separations.

Residual flatness and scale calibration for a point autofocus surface topography measuring instrument (2019)
Journal Article
Maculotti, G., Feng, X., Su, R., Galetto, M., & Leach, R. K. (2019). Residual flatness and scale calibration for a point autofocus surface topography measuring instrument. Measurement Science and Technology, 30(7), https://doi.org/10.1088/1361-6501/ab188f

Point autofocus instruments are often used for measuring the surface topography of objects with complex geometry. Determining the metrological characteristics of the instrument is key to ensuring a traceable areal surface topography measurement. In t... Read More about Residual flatness and scale calibration for a point autofocus surface topography measuring instrument.

Assessment of surface topography modifications through feature-based registration of areal topography data (2019)
Journal Article
Moretti, M., Gambucci, G., Leach, R., & Senin, N. (2019). Assessment of surface topography modifications through feature-based registration of areal topography data. Surface Topography: Metrology and Properties, 7(2), https://doi.org/10.1088/2051-672X/ab152a

Surface topography modifications due to wear or other factors are usually investigated by visual and microscopic inspection, and – when quantitative assessment is required – through the computation of surface texture parameters. However, the current... Read More about Assessment of surface topography modifications through feature-based registration of areal topography data.

All-optical difference engine for in-process defect inspection for roll-to-roll printed electronics (2019)
Journal Article
Feng, X., Su, R., Happonen, T., Liu, J., & Leach, R. (2019). All-optical difference engine for in-process defect inspection for roll-to-roll printed electronics. Proceedings of SPIE, 11053, https://doi.org/10.1117/12.2511140

© 2019 SPIE. The increasing capabilities of roll-to-roll (R2R) printing processes present challenges for quality control, requiring inprocess inspection of large substrates with high resolution at high speed. In this paper, an all-optical difference... Read More about All-optical difference engine for in-process defect inspection for roll-to-roll printed electronics.

Mathematical approach to the validation of functional surface texture parameter software (2019)
Journal Article
Todhunter, L., Leach, R., Lawes, S., Harris, P., & Blateyron, F. (2019). Mathematical approach to the validation of functional surface texture parameter software. Surface Topography: Metrology and Properties, 7(1), Article 015020. https://doi.org/10.1088/2051-672X/ab07ca

A new method for performance validation of surface texture parameter calculation software is introduced, focussing on functional surface texture parameters. Material ratio curves are defined algebraically and used to calculate functional surface text... Read More about Mathematical approach to the validation of functional surface texture parameter software.

Resolution enhancement for topography measurement of high-dynamic-range surfaces via image fusion (2018)
Journal Article
Wang, J., Su, R., Leach, R., Lu, W., Zhou, L., & Jiang, X. (2018). Resolution enhancement for topography measurement of high-dynamic-range surfaces via image fusion. Optics Express, 26(26), 34805-34819. https://doi.org/10.1364/OE.26.034805

In this paper, we introduce a method and algorithm for resolution enhancement of low-resolution surface topography data by fusing it with corresponding high-resolution intensity images. This fusion is carried out by linking the three-dimensional topo... Read More about Resolution enhancement for topography measurement of high-dynamic-range surfaces via image fusion.

Imaging beyond the fundamental slope limit in surface metrology using fluorophore-aided scattering microscopy (2018)
Presentation / Conference
Liu, J., Liu, C., Li, L., Su, R., & Leach, R. (2018, November). Imaging beyond the fundamental slope limit in surface metrology using fluorophore-aided scattering microscopy. Paper presented at Special Interest Group Meeting: Structured & Freeform Surfaces

Topography measurement for smooth surfaces with high slopes, e.g. freeform optics, is a challenging task for optical measuring instruments as the light reflected by the tilted surface cannot be sufficiently collected by the objective, resulting in lo... Read More about Imaging beyond the fundamental slope limit in surface metrology using fluorophore-aided scattering microscopy.

Areal topography measurement of metal additive surfaces using focus variation microscopy (2018)
Journal Article
Newton, L., Senin, N., Gomez, C., Danzl, R., Helmli, F., Blunt, L., & Leach, R. (2019). Areal topography measurement of metal additive surfaces using focus variation microscopy. Additive Manufacturing, 25, 365-389. https://doi.org/10.1016/j.addma.2018.11.013

In this work, the performance of a focus variation instrument for measurement of areal topography of metal additive surfaces was investigated. Samples were produced using both laser and electron beam powder bed fusion processes with some of the most... Read More about Areal topography measurement of metal additive surfaces using focus variation microscopy.

Mechanical vibration bandgaps in surface-based lattices (2018)
Journal Article
Elmadih, W., Syam, W. P., Maskery, I., Chronopoulos, D., & Leach, R. (2019). Mechanical vibration bandgaps in surface-based lattices. Additive Manufacturing, 25, 421-429. https://doi.org/10.1016/j.addma.2018.11.011

In this paper, the phonon dispersion curves of several surface-based lattices are examined, and their energy transmission spectra, along with the corresponding bandgaps are identified. We demonstrate that these bandgaps may be controlled, or tuned, t... Read More about Mechanical vibration bandgaps in surface-based lattices.

Rapid tracking of extrinsic projector parameters in fringe projection using machine learning (2018)
Journal Article
Stavroulakis, P., Chen, S., Delorme, C., Bointon, P., Tzimiropoulos, G., & Leach, R. (2019). Rapid tracking of extrinsic projector parameters in fringe projection using machine learning. Optics and Lasers in Engineering, 114, 7-14. https://doi.org/10.1016/j.optlaseng.2018.08.018

In this work, we propose to enable the angular re-orientation of a projector within a fringe projection system in real-time without the need for re-calibrating the system. The estimation of the extrinsic orientation parameters of the projector is per... Read More about Rapid tracking of extrinsic projector parameters in fringe projection using machine learning.

Verification of a rigorous 2D model of rough surface scattering (2018)
Conference Proceeding
Thomas, M., Leach, R., Nikolaev, N., Widjanarko, T., Senin, N., Aryan, H., & Coupland, J. (2018). Verification of a rigorous 2D model of rough surface scattering.

A rigorous two-dimensional (2D) model of electromagnetic surface scatter has been developed, based on a boundary element method (BEM) established by Simonsen [1]. Simulated far-field scatter is compared to that measured from a laser scatterometer for... Read More about Verification of a rigorous 2D model of rough surface scattering.

Development of mathematical reference standards for the validation of surface texture parameter calculation software (2018)
Conference Proceeding
Todhunter, L., Leach, R., Lawes, S., Blateyron, F., & Harris, P. (2018). Development of mathematical reference standards for the validation of surface texture parameter calculation software. In n/a

A framework for the validation of surface texture parameter calculation software is proposed. The framework utilises mathematically defined surfaces and mathematically calculated surface texture parameter values to produce a reference against which t... Read More about Development of mathematical reference standards for the validation of surface texture parameter calculation software.

In-process measurement of the surface quality for a novel finishing process for polymer additive manufacturing (2018)
Journal Article
Syam, W. P., Leach, R., Rybalcenko, K., Gaio, A., & Crabtree, J. (2018). In-process measurement of the surface quality for a novel finishing process for polymer additive manufacturing. Procedia CIRP, 75, 108-113. https://doi.org/10.1016/j.procir.2018.04.088

In the last decade, there has been considerable growth in the production of end-use polymer parts and components using additive manufacturing methods. A wide range of polymers, from Nylon-12 to thermoplastic polyurethane polymers, can be processed wi... Read More about In-process measurement of the surface quality for a novel finishing process for polymer additive manufacturing.

Information-rich surface metrology (2018)
Journal Article
Senin, N., & Leach, R. K. (2018). Information-rich surface metrology. Procedia CIRP, 75, 19-26. https://doi.org/10.1016/j.procir.2018.05.003

Information-rich metrology refers to the incorporation of any type of available information in the data acquisition and processing pipeline of a measurement process, in order to improve the efficiency and quality of the measurement. In this work, the... Read More about Information-rich surface metrology.

An interlaboratory comparison of X-ray computed tomography measurement for texture and dimensional characterisation of additively manufactured parts (2018)
Journal Article
Townsend, A., Racasan, R., Leach, R., Senin, N., Thompson, A., Ramsey, A., …Blunt, L. (2018). An interlaboratory comparison of X-ray computed tomography measurement for texture and dimensional characterisation of additively manufactured parts. Additive Manufacturing, 23, 422-432. https://doi.org/10.1016/j.addma.2018.08.013

This paper presents the results of the CT-STARR (CT-Surface Texture for Additive Round Robin) Stage 1 interlaboratory comparison. The study compared the results obtained for the extraction of areal surface texture data per ISO 25178-2 from five X-ray... Read More about An interlaboratory comparison of X-ray computed tomography measurement for texture and dimensional characterisation of additively manufactured parts.

Curvature-based segmentation of powder bed point clouds for in-process monitoring (2018)
Conference Proceeding
Chung Chee Law, A., Southon, N., Senin, N., Stavroulakis, P., Leach, R., Goodridge, R., & Kong, Z. (2018). Curvature-based segmentation of powder bed point clouds for in-process monitoring. In 29th Annual International Solid Freeform Fabrication Symposium - an Additive Manufacturing Conference 2018

This paper presents a curvature-based analysis of point clouds collected in-process with fringe projection in a polymer powder bed fusion process. The three-dimensional point clouds were obtained from outside of the build chamber with a fringe projec... Read More about Curvature-based segmentation of powder bed point clouds for in-process monitoring.

In-process measurement and monitoring of a polymer laser sintering powder bed with fringe projection (2018)
Journal Article
Southon, N., Stavroulakis, P., Goodridge, R., & Leach, R. (2018). In-process measurement and monitoring of a polymer laser sintering powder bed with fringe projection. Materials and Design, 157, 227-234. https://doi.org/10.1016/j.matdes.2018.07.053

We investigate the feasibility of using fringe projection to monitor the powder bed of a polyamide 12 polymer laser sintering machine. In particular, we demonstrate the ability of fringe projection to identify a number of defects arising during the p... Read More about In-process measurement and monitoring of a polymer laser sintering powder bed with fringe projection.

Band gap behavior of optimal one-dimensional composite structures with an additive manufactured stiffener (2018)
Journal Article
Ampatzidis, T., Leach, R. K., Tuck, C., & Chronopoulos, D. (2018). Band gap behavior of optimal one-dimensional composite structures with an additive manufactured stiffener. Composites Part B: Engineering, 153, https://doi.org/10.1016/j.compositesb.2018.07.012

In this work, the banded behaviour of composite one-dimensional structures with an additive manufactured stiffener is examined. A finite element method is used to calculate the stiffness, mass and damping matrices, and periodic structure theory is us... Read More about Band gap behavior of optimal one-dimensional composite structures with an additive manufactured stiffener.

Error modelling and validation of a high-precision five degree of freedom hybrid mechanism for high-power high-repetition rate laser operations (2018)
Journal Article
Karim, S., Piano, S., Leach, R. K., & Tolley, M. (2018). Error modelling and validation of a high-precision five degree of freedom hybrid mechanism for high-power high-repetition rate laser operations. Precision Engineering, 54, 182-197. https://doi.org/10.1016/j.precisioneng.2018.04.018

The accuracy, repeatability and speed requirements of high-power laser operations demand the employment of five degree of freedom motion control solutions that are capable of positioning and orientating the target with respect to the laser(s)-target... Read More about Error modelling and validation of a high-precision five degree of freedom hybrid mechanism for high-power high-repetition rate laser operations.

A programmable software framework for the generation of simulated surface topography (2018)
Conference Proceeding
Todhunter, L. D., Senin, N., Leach, R., Lawes, S., Blateyron, F., & Harris, P. (2018). A programmable software framework for the generation of simulated surface topography.

A flexible and programmable software framework has been developed that enables the creation of simulated, areal surface topography datasets. The framework allows the creation of surfaces through a layered approach where deterministic topographic stru... Read More about A programmable software framework for the generation of simulated surface topography.

The effects of vibration on fringe projection systems (2018)
Conference Proceeding
Bointon, P., Todhunter, L., Stavroulakis, P., Clare, A., & Leach, R. (2018). The effects of vibration on fringe projection systems.

Mechanical vibration noise is a significant source of error in precision measuring instruments. Errors due to vibration can be detected in measurement signals, and so methods to control mechanical vibration must be considered throughout the design pr... Read More about The effects of vibration on fringe projection systems.

Lateral error compensation for focus variation microscopy (2018)
Conference Proceeding
Pérez, P., Syam, W. P., Albajez, J. A., Santolaria, J., & Leach, R. (2018). Lateral error compensation for focus variation microscopy.

Focus variation microscopy measures both the areal form and areal surface texture of components. Improvements to the accuracy and precision of focus variation microscopes usually requires measurements with multiple image-fields to compensate lateral... Read More about Lateral error compensation for focus variation microscopy.

Feature-based characterisation of evolving surface topographies in finishing operations for additive manufacturing (2018)
Presentation / Conference
Newton, L., Senin, N., Smith, B., & Leach, R. (2018, June). Feature-based characterisation of evolving surface topographies in finishing operations for additive manufacturing. Paper presented at 18th International Conference and Exhibition (euspan)

Finishing operations play a fundamental role in the additive manufacture of components. Conventional surface metrology solutions allow for the characterisation of surface roughness through texture parameters, but are not fully suitable to capture the... Read More about Feature-based characterisation of evolving surface topographies in finishing operations for additive manufacturing.

Photogrammetric coordinate metrology (2018)
Presentation / Conference
Sims-Waterhouse, D., Piano, S., & Leach, R. (2018, June). Photogrammetric coordinate metrology. Paper presented at euspen 18th International Conference & Exhibition

Effects of vibration on fringe projection systems (2018)
Presentation / Conference
Bointon, P., Todhunter, L., Stavroulakis, P., Clare, A., & Leach, R. (2018, June). Effects of vibration on fringe projection systems. Paper presented at euspen 18th International Conference & Exhibition

Development of an X-ray simulator: from STTL file to grey scale image (2018)
Conference Proceeding
Korner, L., Leach, R., & Lawes, S. (2018). Development of an X-ray simulator: from STTL file to grey scale image. In Proceedings of the 18th International conference of the European Society for Precision Engineering and Nanotechnology (euspen), 503-504

Fast and cost-effective in-process defect inspection for printed electronics based on coherent optical processing (2018)
Journal Article
Feng, X., Su, R., Happonen, T., Liu, J., & Leach, R. (2018). Fast and cost-effective in-process defect inspection for printed electronics based on coherent optical processing. Optics Express, 26(11), https://doi.org/10.1364/OE.26.013927

This paper presents an all-optical difference engine (AODE) sensor for detecting the defects in printed electronics produced with roll-to-roll processes. The sensor is based on the principle of coherent optical subtraction and is able to achieve high... Read More about Fast and cost-effective in-process defect inspection for printed electronics based on coherent optical processing.

A self-calibration rotational stitching method for precision measurement of revolving surfaces (2018)
Journal Article
Liu, M., Cheung, C., Feng, X., Wang, C., & Leach, R. (in press). A self-calibration rotational stitching method for precision measurement of revolving surfaces. Precision Engineering, https://doi.org/10.1016/j.precisioneng.2018.05.002

When measuring revolving objects, it is often desired to obtain not only the geometrical form of the workpiece, but also the topography of the surface, as they both affect the performance of the part. However, holistic measurement of the entire three... Read More about A self-calibration rotational stitching method for precision measurement of revolving surfaces.

Fusion of photogrammetry and coherence scanning interferometry data for all-optical coordinate measurement (2018)
Journal Article
Leach, R., Sims-Waterhouse, D., Medeossi, F., Savio, E., Carmignato, S., & Su, R. (2018). Fusion of photogrammetry and coherence scanning interferometry data for all-optical coordinate measurement. CIRP Annals - Manufacturing Technology, 67(1), 599-602. https://doi.org/10.1016/j.cirp.2018.04.043

Multisensor data fusion is an approach to enlarge the potential applicability of measuring techniques and improve accuracy, taking advantage of the strengths of different techniques. In this work, we present a new method for the fusion of photogramme... Read More about Fusion of photogrammetry and coherence scanning interferometry data for all-optical coordinate measurement.

Hierarchical-information-based characterization of multiscale structured surfaces (2018)
Journal Article
Cheung, C. F., Liu, M., Leach, R., Feng, X., & Zhao, C. (2018). Hierarchical-information-based characterization of multiscale structured surfaces. CIRP Annals - Manufacturing Technology, 67(1), 539-542. https://doi.org/10.1016/j.cirp.2018.04.002

© 2018 This paper presents a hierarchical-information-based characterization method for multiscale structured surfaces. The method makes use of a priori information of the multiscale surface and a hierarchical segmentation–registration (HSR) algorith... Read More about Hierarchical-information-based characterization of multiscale structured surfaces.

Effects of magnification and sampling resolution in X-ray computed tomography for the measurement of additively manufactured metal surfaces (2018)
Journal Article
Thompson, A., Senin, N., Maskery, I., & Leach, R. (2018). Effects of magnification and sampling resolution in X-ray computed tomography for the measurement of additively manufactured metal surfaces. Precision Engineering, 53, https://doi.org/10.1016/j.precisioneng.2018.02.014

Recent studies have shown that X-ray computed tomography (XCT) can be used to measure the surface topography of additively manufactured parts. However, further research is necessary to fully understand XCT measurement performance. Here, we show how m... Read More about Effects of magnification and sampling resolution in X-ray computed tomography for the measurement of additively manufactured metal surfaces.

Lateral scale calibration for focus variation microscopy (2018)
Journal Article
Alburayt, A., Syam, W. P., & Leach, R. (in press). Lateral scale calibration for focus variation microscopy. Measurement Science and Technology, 29(6), https://doi.org/10.1088/1361-6501/aab949

Areal surface texture measuring instruments can be calibrated by determining a set of metrological characteristics currently in the final stages of standardisation. In this paper, amplification, linearity and perpendicularity characteristics have bee... Read More about Lateral scale calibration for focus variation microscopy.

Noise evaluation of a point autofocus surface topography measuring instrument (2018)
Journal Article
Maculotti, G., Feng, X., Galetto, M., & Leach, R. K. (2018). Noise evaluation of a point autofocus surface topography measuring instrument. Measurement Science and Technology, 29(6), https://doi.org/10.1088/1361-6501/aab528

In this work, the measurement noise of a point autofocus surface topography measuring instrument is evaluated, as the first step towards establishing a route to traceability for this type of instrument. The evaluation is based on the determination of... Read More about Noise evaluation of a point autofocus surface topography measuring instrument.

Internal surface measurement of metal powder bed fusion parts (2018)
Journal Article
Thompson, A., Senin, N., Maskery, I., Körner, L., Lawes, S., & Leach, R. (2018). Internal surface measurement of metal powder bed fusion parts. Additive Manufacturing, 20, https://doi.org/10.1016/j.addma.2018.01.003

Recent advances in X-ray computed tomography (XCT) have allowed for measurement resolutions approaching the point where XCT can be used for measuring surface topography. These advances make XCT appealing for measuring hard-to-reach or internal surfac... Read More about Internal surface measurement of metal powder bed fusion parts.

Effects of defocus on the transfer function of coherence scanning interferometry (2017)
Journal Article
Su, R., Thomas, M., Leach, R., & Coupland, J. (2017). Effects of defocus on the transfer function of coherence scanning interferometry. Optics Letters, 43(1), https://doi.org/10.1364/OL.43.000082

Coherence scanning interferometry (CSI) offers three dimensional (3D) measurement of surface topography with high precision and accuracy. Defocus within the interferometric objective lens, however, is commonly present in CSI measurements, and reduces... Read More about Effects of defocus on the transfer function of coherence scanning interferometry.

Feature-based characterisation of signature topography in laser powder bed fusion of metals (2017)
Journal Article
Senin, N., Thompson, A., & Leach, R. K. (2018). Feature-based characterisation of signature topography in laser powder bed fusion of metals. Measurement Science and Technology, 29(4), Article 045009. https://doi.org/10.1088/1361-6501/aa9e19

The use of state-of-the-art areal topography measurement instrumentation allows for a high level of detail in the acquisition of topographic information at micrometric scales. The three-dimensional geometric models of surface topography obtained from... Read More about Feature-based characterisation of signature topography in laser powder bed fusion of metals.

Development of mathematically-defined surfaces (2017)
Conference Proceeding
Todhunter, L. D., Leach, R., Lawes, S., Harris, P., & Blateyron, F. (2017). Development of mathematically-defined surfaces.

New software has been developed that enables the creation of areal surface topography representations. The goal of this software package is to utilise the mathematically-defined surface representations in the development of surface texture parameter... Read More about Development of mathematically-defined surfaces.

3-dimensional inkjet printing of macro structures from silver nanoparticles (2017)
Journal Article
Vaithilingam, J., Saleh, E., Körner, L., Wildman, R. D., Hague, R. J., Leach, R. K., & Tuck, C. J. (2018). 3-dimensional inkjet printing of macro structures from silver nanoparticles. Materials and Design, 139, https://doi.org/10.1016/j.matdes.2017.10.070

The adoption of additive manufacturing technology is gaining interest for processing precious metals. In this study, the capability of inkjet printing was explored to fabricate macroscopic parts from commercial silver nanoparticle ink (AgNPs). A besp... Read More about 3-dimensional inkjet printing of macro structures from silver nanoparticles.

Flexible decoupled camera and projector fringe projection system using inertial sensors (2017)
Journal Article
Stavroulakis, P., Sims-Waterhouse, D., Piano, S., & Leach, R. K. (in press). Flexible decoupled camera and projector fringe projection system using inertial sensors. Optical Engineering, 56(10), https://doi.org/10.1117/1.OE.56.10.104106

Measurement of objects with complex geometry and many self occlusions is increasingly important in many fields, including additive manufacturing. In a fringe projection system, the camera and the projector cannot move independently with respect to ea... Read More about Flexible decoupled camera and projector fringe projection system using inertial sensors.

True-color 3D surface metrology for additive manufacturing using interference microscopy (2017)
Conference Proceeding
DiSciacca, J., Gomez, C., Thompson, A., Lawes, S., Leach, R., Colonna de Lega, X., & de Groot, P. (2017). True-color 3D surface metrology for additive manufacturing using interference microscopy.

Coherence scanning interferometry (CSI) is widely used for surface topography characterisation. With the ability to measure both rough surfaces with the high slopes and optical finishes, CSI has made contibutions in fields from industrial machining t... Read More about True-color 3D surface metrology for additive manufacturing using interference microscopy.

Optimisation of surface topography characterisation for metal additive manufacturing using coherence scanning interferometry (2017)
Conference Proceeding
Gómez, C. A., Su, R., Thompson, A., DiSciacca, J., Lawes, S., & Leach, R. K. (2017). Optimisation of surface topography characterisation for metal additive manufacturing using coherence scanning interferometry.

The surface topography of metal additive manufactured (AM) parts can be challenging to measure due to the presence of complex features, such as high slopes, step like recesses and protuberances, and local variations in reflectance. Recent innovations... Read More about Optimisation of surface topography characterisation for metal additive manufacturing using coherence scanning interferometry.

Feature-based characterisation of laser powder bed fusion surfaces (2017)
Conference Proceeding
Senin, N., Thompson, A., & Leach, R. K. (2017). Feature-based characterisation of laser powder bed fusion surfaces.

A novel algorithmic pipeline for the automated identification and dimensional/geometric characterisation of topographic formations of interest (surface features) is proposed, specifically aimed at the investigation of signature features left by laser... Read More about Feature-based characterisation of laser powder bed fusion surfaces.

Defect evolution in laser powder bed fusion additive manufactured components during thermo-mechanical testing (2017)
Conference Proceeding
Xu, Z., Hyde, C. J., Thompson, A., Leach, R. K., Maskery, I., Tuck, C., & Clare, A. T. (2017). Defect evolution in laser powder bed fusion additive manufactured components during thermo-mechanical testing.

The mechanical performance of additively manufactured (AM) components remains an issue, limiting the implementation of AM technologies. In this work, a new method is presented, to examine the evolution of defects in an Inconel 718 two-bar test specim... Read More about Defect evolution in laser powder bed fusion additive manufactured components during thermo-mechanical testing.

Design and analysis of strut-based lattice structures for vibration isolation (2017)
Journal Article
Syam, W. P., Jianwei, W., Zhao, B., Maskery, I., Elmadih, W., & Leach, R. (2018). Design and analysis of strut-based lattice structures for vibration isolation. Precision Engineering, 51, 494-506. https://doi.org/10.1016/j.precisioneng.2017.09.010

This paper presents the design, analysis and experimental verification of strut-based lattice structures to enhance the mechanical vibration isolation properties of a machine frame, whilst also conserving its structural integrity. In addition, design... Read More about Design and analysis of strut-based lattice structures for vibration isolation.

Characterisation of the topography of metal additive surface features with different measurement technologies (2017)
Journal Article
Senin, N., Thompson, A., & Leach, R. K. (2017). Characterisation of the topography of metal additive surface features with different measurement technologies. Measurement Science and Technology, 28(9), Article 095003. https://doi.org/10.1088/1361-6501/aa7ce2

© 2017 IOP Publishing Ltd. The challenges of measuring the surface topography of metallic surfaces produced by additive manufacturing are investigated. The differences between measurements made using various optical and non-optical technologies, incl... Read More about Characterisation of the topography of metal additive surface features with different measurement technologies.

The application of composite through-thickness assessment to additively manufactured structures (2017)
Conference Proceeding
Bitar, I., Aboulkhair, N., & Leach, R. (2017). The application of composite through-thickness assessment to additively manufactured structures. In Solid Freeform Fabrication 2017: Proceedings of the 28th Annual International Solid Freeform Fabrication Symposium – An Additive Manufacturing Conference (616-632)

This study looks into the applicability of through-thickness assessment to additive manufacturing (AM) carbon-fibre reinforced polymers (CFRPs). The study utilised a material extrusion printer that uses fused filament fabrication and composite filame... Read More about The application of composite through-thickness assessment to additively manufactured structures.

Staged thermomechanical testing of nickel superalloys produced by selective laser melting (2017)
Journal Article
Xu, Z., Hyde, C. J., Thompson, A., Leach, R. K., Maskery, I., Tuck, C., & Clare, A. T. (2017). Staged thermomechanical testing of nickel superalloys produced by selective laser melting. Materials and Design, 133, 520-527. https://doi.org/10.1016/j.matdes.2017.08.009

The creep performance of additively manufactured components remains an issue before additive manufacturing can be put fully implemented. In this study, Inconel 718 two-bar specimens are produced by selective laser melting and subjected to a ‘staged’... Read More about Staged thermomechanical testing of nickel superalloys produced by selective laser melting.

High-precision lateral distortion measurement and correction in coherence scanning interferometry using an arbitrary surface (2017)
Journal Article
Ekberg, P., Su, R., & Leach, R. K. (2017). High-precision lateral distortion measurement and correction in coherence scanning interferometry using an arbitrary surface. Optics Express, 25(16), https://doi.org/10.1364/OE.25.018703

Lateral optical distortion is present in most optical imaging systems. In coherence scanning interferometry, distortion may cause field-dependent systematic errors in the measurement of surface topography. These errors become critical when high-preci... Read More about High-precision lateral distortion measurement and correction in coherence scanning interferometry using an arbitrary surface.

Optimization of surface measurement for metal additive manufacturing using coherence scanning interferometry (2017)
Journal Article
Gomez, C., Su, R., Thompson, A., DiSciacca, J., Lawes, S., & Leach, R. K. (2017). Optimization of surface measurement for metal additive manufacturing using coherence scanning interferometry. Optical Engineering, 56(11), 1-8. https://doi.org/10.1117/1.OE.56.11.111714

Surface topography measurement for metal additive manufacturing (AM) is a challenging task for contact and non-contact methods. In this paper, we present an experimental investigation of the use of coherence scanning interferometry (CSI) for measurem... Read More about Optimization of surface measurement for metal additive manufacturing using coherence scanning interferometry.

Industrial survey of ISO surface texture parameters (2017)
Journal Article
Todhunter, L. D., Leach, R., Lawes, S., & Blateyron, F. (2017). Industrial survey of ISO surface texture parameters. CIRP Journal of Manufacturing Science and Technology, 19, https://doi.org/10.1016/j.cirpj.2017.06.001

Results of an international survey are presented, detailing the use of surface texture parameters in industry. The survey received 179 responses from a total of 34 countries, revealing the use of a variety of parameters from ISO 4287, ISO 12085, ISO... Read More about Industrial survey of ISO surface texture parameters.

Results of an industrial survey on the use of surface texture parameters (2017)
Conference Proceeding
Todhunter, L. D., Leach, R., & Lawes, S. (2017). Results of an industrial survey on the use of surface texture parameters.

In 1999, CIRP conducted an industrial survey of the use of surface texture parameters [1]. In the seventeen years since, much has changed, with the most important advancement being the introduction of areal surface texture parameters as described in... Read More about Results of an industrial survey on the use of surface texture parameters.

Design of mechanically-optimised lattice structures for vibration isolation (2017)
Conference Proceeding
Syam, W. P., Jianwei, W., Zhao, B., Maskery, I., & Leach, R. K. (2017). Design of mechanically-optimised lattice structures for vibration isolation.

In this study, we investigate the use of additively manufactured strut-based lattice structures to enhance the mechanical vibration isolation properties of a structure. Three lattice designs, inspired by the common strut-based lattice structures, are... Read More about Design of mechanically-optimised lattice structures for vibration isolation.

Detecting the signature of motion stage non-linearity for focus variation microscopy using measurement noise and surface topography repeatability (2017)
Conference Proceeding
Alburayt, A., Syam, W. P., & Leach, R. (2017). Detecting the signature of motion stage non-linearity for focus variation microscopy using measurement noise and surface topography repeatability.

Measurement noise is one of the ISO-proposed metrological characteristics of areal surface texture instruments [1, 2, 3, 4]. Measurement noise includes all of the unwanted contributions to the output signals when the instrument is used in its normal... Read More about Detecting the signature of motion stage non-linearity for focus variation microscopy using measurement noise and surface topography repeatability.

Measurement noise of a point autofocus surface topography instrument (2017)
Conference Proceeding
Feng, X., Quagliotti, D., Maculotti, G., Syam, W. P., Tosello, G., Hansen, H. N., …Leach, R. (2017). Measurement noise of a point autofocus surface topography instrument.

Optical instruments for areal topography measurement can be especially sensitive to noise when scanning is required. Such noise has different sources, including those internally generated and external sources from the environment [1].For some instrum... Read More about Measurement noise of a point autofocus surface topography instrument.

Coherence scanning interferometry for additive manufacture (2017)
Conference Proceeding
Gomez, C., Thompson, A., DiSciacca, J., Lawes, S., & Leach, R. (2017). Coherence scanning interferometry for additive manufacture.

Additive manufacture (AM) of metal components is a rapidly maturing technology; but given the large number of interrelated process parameters, it remains difficult to control to high precision. It has been observed that processing conditions may be a... Read More about Coherence scanning interferometry for additive manufacture.

Focus variation measurement of electron beam melted surfaces (2017)
Conference Proceeding
Newton, L., Senin, N., & Leach, R. (2017). Focus variation measurement of electron beam melted surfaces.

Electron beam melting (EBM) is a promising additive manufacturing process which is seeing increasing use in high value manufacturing sectors such as aerospace [1]. With its layer-by-layer approach, EBM can allow the creation of parts of complex shape... Read More about Focus variation measurement of electron beam melted surfaces.

X-ray computed tomography of additively manufactured metal parts: the effect of magnification and reconstruction sampling on surface topography measurement (2017)
Conference Proceeding
Thompson, A., Körner, L., Senin, N., Lawes, S., Leach, R., & Maskery, I. (2017). X-ray computed tomography of additively manufactured metal parts: the effect of magnification and reconstruction sampling on surface topography measurement.

X-ray computed tomography (XCT) has recently become recognised as a viable method of surface topography measurement for additively manufactured (AM) metal parts [1–5]. AM is capable of producing internal features that are inaccessible to other surfac... Read More about X-ray computed tomography of additively manufactured metal parts: the effect of magnification and reconstruction sampling on surface topography measurement.

An industrial survey on the use of surface texture parameters (2017)
Conference Proceeding
Todhunter, L. D., Leach, R., & Lawes, S. D. (2017). An industrial survey on the use of surface texture parameters.

In 1999, CIRP conducted an industrial survey of the use of surface texture parameters [1]. In the seventeen years since, much has changed, with the most important advancement being the introduction of areal surface texture parameters as described in... Read More about An industrial survey on the use of surface texture parameters.

Tolerance on sphere radius for the calibration of the transfer function of coherence scanning interferometry (2017)
Conference Proceeding
Su, R., Coupland, J. M., Wang, Y., & Leach, R. K. (2017). Tolerance on sphere radius for the calibration of the transfer function of coherence scanning interferometry. In P. Lehmann, W. Osten, & A. Albertazzi Gonçalves (Eds.), Proceedings Volume 10329 Optical Measurement Systems for Industrial Inspection X. https://doi.org/10.1117/12.2272041

Although coherence scanning interferometry (CSI) commonly achieves a sub-nanometre noise level in surface topography measurement, the absolute accuracy is difficult to determine when measuring a surface that contains varying local slope angles and cu... Read More about Tolerance on sphere radius for the calibration of the transfer function of coherence scanning interferometry.

X-ray computed tomography and additive manufacturing in medicine: a review (2017)
Journal Article
Thompson, A., McNally, D., Maskery, I., & Leach, R. K. (in press). X-ray computed tomography and additive manufacturing in medicine: a review. International Journal of Metrology and Quality Engineering, 8, Article 17. https://doi.org/10.1051/ijmqe/2017015

The use of X-ray computed tomography (XCT) with additive manufacture (AM) within a medical context is examined in this review. The seven AM process families and various XCT scanning techniques are explained in brief, and the use of these technologies... Read More about X-ray computed tomography and additive manufacturing in medicine: a review.

An analysis of type F2 software measurement standards for profile surface texture parameters (2017)
Journal Article
Todhunter, L. D., Leach, R. K., Lawes, S., & Blateyron, F. (2017). An analysis of type F2 software measurement standards for profile surface texture parameters. Measurement Science and Technology, 28(6), Article 065017. https://doi.org/10.1088/1361-6501/aa6924

This paper reports on an in-depth analysis of ISO 5436 part 2 type F2 reference software for the calculation of profile surface texture parameters that has been performed on the input, implementation and output results of the reference software devel... Read More about An analysis of type F2 software measurement standards for profile surface texture parameters.

Topography of selectively laser melted surfaces: A comparison of different measurement methods (2017)
Journal Article
Thompson, A., Senin, N., Giusca, C. L., & Leach, R. K. (2017). Topography of selectively laser melted surfaces: A comparison of different measurement methods. CIRP Annals - Manufacturing Technology, 66(1), 543-546. https://doi.org/10.1016/j.cirp.2017.04.075

Selective laser melting (SLM) of metals produces surface topographies that are challenging to measure. Multiple areal surface topography measurement technologies are available, which allow reconstruction of information rich, three-dimensional digital... Read More about Topography of selectively laser melted surfaces: A comparison of different measurement methods.

Verification of micro-scale photogrammetry for smooth three-dimensional object measurement (2017)
Journal Article
Sims-Waterhouse, D., Piano, S., & Leach, R. (2017). Verification of micro-scale photogrammetry for smooth three-dimensional object measurement. Measurement Science and Technology, 28(5), Article 055010. https://doi.org/10.1088/1361-6501/aa6364

© 2017 IOP Publishing Ltd. By using sub-millimetre laser speckle pattern projection we show that photogrammetry systems are able to measure smooth three-dimensional objects with surface height deviations less than 1 μm. The projection of laser speckl... Read More about Verification of micro-scale photogrammetry for smooth three-dimensional object measurement.

Optical difference engine for defect inspection in highly-parallel manufacturing processes (2017)
Conference Proceeding
Feng, X., Su, R., Liu, M., & Leach, R. K. (2017). Optical difference engine for defect inspection in highly-parallel manufacturing processes.

Traditional defect inspection for highly-parallel manufacturing processes requires the processing of large measurement datasets, which is often not fast enough for in-situ inspection of large areas with high resolution. This study develops an all-opt... Read More about Optical difference engine for defect inspection in highly-parallel manufacturing processes.

On tilt and curvature dependent errors and the calibration of coherence scanning interferometry (2017)
Journal Article
Su, R., Wang, Y., Coupland, J., & Leach, R. K. (in press). On tilt and curvature dependent errors and the calibration of coherence scanning interferometry. Optics Express, 25(4), https://doi.org/10.1364/OE.25.003297

Although coherence scanning interferometry (CSI) is capable of measuring surface topography with sub-nanometre precision, it is well known that the performance of measuring instruments depends strongly on the local tilt and curvature of the sample su... Read More about On tilt and curvature dependent errors and the calibration of coherence scanning interferometry.

Combined inkjet printing and infrared sintering of silver nanoparticles using a swathe-by-swathe and layer-by-layer approach for 3-dimensional structures (2017)
Journal Article
Vaithilingam, J., Simonelli, M., Saleh, E., Senin, N., Wildman, R. D., Hague, R. J. M., …Tuck, C. J. (2017). Combined inkjet printing and infrared sintering of silver nanoparticles using a swathe-by-swathe and layer-by-layer approach for 3-dimensional structures. ACS Applied Materials and Interfaces, 9(7), 6560-6570. https://doi.org/10.1021/acsami.6b14787

Despite the advancement of additive manufacturing (AM)/3-dimensional (3D) printing, single-step fabrication of multifunctional parts using AM is limited. With the view of enabling multifunctional AM (MFAM), in this study, sintering of metal nanoparti... Read More about Combined inkjet printing and infrared sintering of silver nanoparticles using a swathe-by-swathe and layer-by-layer approach for 3-dimensional structures.

Aerial wetting contact angle measurement using confocal microscopy (2016)
Journal Article
Chesna, J. W., Wiedmaier, B. F., Wang, J., Samara, A., Leach, R. K., Her, T., & Smith, S. T. (in press). Aerial wetting contact angle measurement using confocal microscopy. Measurement Science and Technology, 27(12), https://doi.org/10.1088/0957-0233/27/12/125202

A method is presented in which the wetting contact angle of a sessile drop is acquired aerially using confocal techniques to measure the radius and the height of a droplet deposited on a planar surface. The repeatability of this method is typically l... Read More about Aerial wetting contact angle measurement using confocal microscopy.

Assessing the capability of in-situ nondestructive analysis during layer based additive manufacture (2016)
Journal Article
Hirsch, M., Patel, R., Li, W., Guan, G., Leach, R. K., Sharples, S. D., & Clare, A. T. (2017). Assessing the capability of in-situ nondestructive analysis during layer based additive manufacture. Additive Manufacturing, 13, 135-142. https://doi.org/10.1016/j.addma.2016.10.004

Unlike more established subtractive or constant volume manufacturing technologies, additive manufacturing methods suffer from a lack of in-situ monitoring methodologies which can provide informationrelating to process performance and the formation of... Read More about Assessing the capability of in-situ nondestructive analysis during layer based additive manufacture.

Shape descriptors and statistical classification on areal topography data for tile inspection in tessellated surfaces (2016)
Journal Article
Senin, N., Moretti, M., & Leach, R. K. (2017). Shape descriptors and statistical classification on areal topography data for tile inspection in tessellated surfaces. Measurement, 95, https://doi.org/10.1016/j.measurement.2016.09.044

Verification of conformance to design specifications in production, and identification of defects related to wear or other damage during maintenance, are key metrological aspects that must be addressed for micro-scale tessellated surfaces. A new algo... Read More about Shape descriptors and statistical classification on areal topography data for tile inspection in tessellated surfaces.

Study of weighted fusion methods for the measurement of surface geometry (2016)
Journal Article
Wang, J., Pagani, L., Leach, R. K., Zeng, W., Colosimo, B. M., & Zhou, L. (2017). Study of weighted fusion methods for the measurement of surface geometry. Precision Engineering, 47, 111-121. https://doi.org/10.1016/j.precisioneng.2016.07.012

© 2016 Elsevier Inc. Four types of weighted fusion methods, including pixel-level, least-squares, parametrical and non-parametrical, have been classified and theoretically analysed in this study. In particular, the uncertainty propagation of the weig... Read More about Study of weighted fusion methods for the measurement of surface geometry.

Quadrature wavelength scanning interferometry (2016)
Journal Article
Moschetti, G., Forbes, A., Leach, R. K., Jiang, X., & O’Connor, D. (2016). Quadrature wavelength scanning interferometry. Applied Optics, 55(20), 5332-5340. https://doi.org/10.1364/ao.55.005332

A novel method to double the measurement range of wavelength scanning interferometry (WSI) is described. In WSI the measured optical path difference (OPD) is affected by a sign ambiguity, i.e. from an interference signal it is not possible to disting... Read More about Quadrature wavelength scanning interferometry.

Loose powder detection and surface characterization in selective laser sintering via optical coherence tomography (2016)
Journal Article
Guan, G., Hirsch, M., Syam, W. P., Leach, R. K., Huang, Z., & Clare, A. T. (2016). Loose powder detection and surface characterization in selective laser sintering via optical coherence tomography. Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, 472(2191), Article 20160201. https://doi.org/10.1098/rspa.2016.0201

Defects produced during selective laser sintering (SLS) are difficult to non-destructively detect after build completion without the use of X-ray-based methods. Overcoming this issue by assessing integrity on a layer-by-layer basis has become an area... Read More about Loose powder detection and surface characterization in selective laser sintering via optical coherence tomography.

Investigating mechanical characteristics of styli for micro-CMMs (2016)
Conference Proceeding
Ismail, M., Tseng, K., Claverley, J. D., Sheu, D., Chetwynd, D., & Leach, R. K. (2016). Investigating mechanical characteristics of styli for micro-CMMs.

The mechanical characteristics of styli for micro coordinate measuring machines (micro-CMMs) is of importance because of the major effect the styli have on the performance and capability of micro-CMMs. Previous work has focussed on the design of the... Read More about Investigating mechanical characteristics of styli for micro-CMMs.

Towards uncertainty in dimensional metrology of surface features for advanced manufacturing (2016)
Conference Proceeding
Musso, G., Senin, N., Galetto, M., & Leach, R. K. (2016). Towards uncertainty in dimensional metrology of surface features for advanced manufacturing.

In previous work, an original approach was developed for the dimensional characterisation of surface features on parts and test artefacts, aimed at supporting researchers involved in the study of advanced manufacturing processes. In the approach, met... Read More about Towards uncertainty in dimensional metrology of surface features for advanced manufacturing.

An integrated measurement method for complex micro-scale geometries (2016)
Conference Proceeding
Rabani, A., Senin, N., Helmli, F., Butler-Smith, P., & Leach, R. K. (2016). An integrated measurement method for complex micro-scale geometries.

Micro-scale geometries are becoming commonplace in many high-precision manufacturing applications. Micro-drilling processes, for example, are being employed for producing holes in demanding applications involving fluid transfer, atomisers and micro-m... Read More about An integrated measurement method for complex micro-scale geometries.

Phase and fringe order determination in wavelength scanning interferometry (2016)
Journal Article
Moschetti, G., Forbes, A., Leach, R. K., Jiang, X., & O'Connor, D. (2016). Phase and fringe order determination in wavelength scanning interferometry. Optics Express, 24(8), 8997-9012. https://doi.org/10.1364/OE.24.008997

A method to obtain unambiguous surface height measurements using wavelength scanning interferometry with an improved repeatability, comparable to that obtainable using phase shifting interferometry, is reported. Rather than determining the conventio... Read More about Phase and fringe order determination in wavelength scanning interferometry.

Performance assessment of a new variable stiffness probing system for micro-CMMs (2016)
Journal Article
Alblahaihid, K., Kinnell, P., Lawes, S., Desgaches, D., & Leach, R. K. (2016). Performance assessment of a new variable stiffness probing system for micro-CMMs. Sensors, 16(4), Article 492. https://doi.org/10.3390/s16040492

When designing micro-scale tactile probes, a design trade-off must be made between the stiffness and flexibility of the probing element. The probe must be flexible enough to ensure sensitive parts are not damaged during contact, but it must be stiff... Read More about Performance assessment of a new variable stiffness probing system for micro-CMMs.

Review of post-process optical form metrology for industrial-grade metal additive manufactured parts (2016)
Journal Article
Stavroulakis, P., & Leach, R. K. (2016). Review of post-process optical form metrology for industrial-grade metal additive manufactured parts. Review of Scientific Instruments, 87(4), Article 041101. https://doi.org/10.1063/1.4944983

The scope of this review is to investigate the main post-process optical form measurement technologies available in industry today and to determine whether they are applicable to industrial-grade metal additive manufactured parts. An in-depth review... Read More about Review of post-process optical form metrology for industrial-grade metal additive manufactured parts.

Review of in-situ process monitoring and in-situ metrology for metal additive manufacturing (2016)
Journal Article
Everton, S. K., Hirsch, M., Stravroulakis, P., Leach, R. K., & Clare, A. T. (2016). Review of in-situ process monitoring and in-situ metrology for metal additive manufacturing. Materials and Design, 95, 431-445. https://doi.org/10.1016/j.matdes.2016.01.099

Lack of assurance of quality with additively manufactured (AM) parts is a key technological barrier that prevents manufacturers from adopting AM technologies, especially for high-value applications where component failure cannot be tolerated. Develop... Read More about Review of in-situ process monitoring and in-situ metrology for metal additive manufacturing.

Study of manufacturing and measurement reproducibility on a laser textured structured surface (2016)
Journal Article
MacAulay, G. D., Senin, N., Giusca, C. L., & Leach, R. K. (2016). Study of manufacturing and measurement reproducibility on a laser textured structured surface. Measurement, 94, 942-948. https://doi.org/10.1016/j.measurement.2016.03.042

In recent years there has been increasing interest in the use of structured surfaces to provide specific functional performance. Such surfaces often consist of localised micro-scale surface features with predetermined geometries. The performance of t... Read More about Study of manufacturing and measurement reproducibility on a laser textured structured surface.

An international comparison of surface texture parameters quantification on polymer artefacts using optical instruments (2016)
Journal Article
Tosello, G., Haitjema, H., Leach, R. K., Quagliotti, D., Gasparin, S., & Hansen, H. (in press). An international comparison of surface texture parameters quantification on polymer artefacts using optical instruments. CIRP Annals - Manufacturing Technology, 65(1), https://doi.org/10.1016/j.cirp.2016.04.003

An international comparison of optical instruments measuring polymer surfaces with arithmetic mean height values in the sub-micrometre range has been carried out. The comparison involved sixteen optical surface texture instruments (focus variation in... Read More about An international comparison of surface texture parameters quantification on polymer artefacts using optical instruments.

Quantification and characterisation of porosity in selectively laser melted Al–Si10–Mg using x-ray computed tomography (2016)
Journal Article
Maskery, I., Aboulkhair, N., Corfield, M., Tuck, C., Clare, A., Leach, R. K., …Hague, R. J. (2016). Quantification and characterisation of porosity in selectively laser melted Al–Si10–Mg using x-ray computed tomography. Materials Characterization, 111, https://doi.org/10.1016/j.matchar.2015.12.001

We used X-ray computed tomography (CT), microscopy and hardness measurements to study Al–Si10–Mg produced by selective laser melting (SLM). Specimens were subject to a series of heat treatments including annealing and precipitation hardening. The spe... Read More about Quantification and characterisation of porosity in selectively laser melted Al–Si10–Mg using x-ray computed tomography.

Model-based defect detection on structured surfaces having optically unresolved features (2015)
Journal Article
O’Connor, D., Henning, A. J., Sherlock, B., Leach, R., Coupland, J., & Giusca, C. L. (2015). Model-based defect detection on structured surfaces having optically unresolved features. Journal of Optics A: Pure and Applied Optics, 54(30), 8872-8877. https://doi.org/10.1364/AO.54.008872

In this paper, we demonstrate, both numerically and experimentally, a method for the detection of defects on structured surfaces having optically unresolved features. The method makes use of synthetic reference data generated by an observational mode... Read More about Model-based defect detection on structured surfaces having optically unresolved features.

Surface texture measurement for additive manufacturing (2015)
Journal Article
Triantaphyllou, A., Leach, R., Giusca, C. L., Macaulay, G. D., Roerig, F., Hoebel, M., …Milne, K. A. (2015). Surface texture measurement for additive manufacturing. Measurement Science and Technology, 3, Article 024002. https://doi.org/10.1088/2051-672X/3/2/024002

The surface texture of additively manufactured metallic surfaces made by powder bed methods is affected by a number of factors, including the powder's particle size distribution, the effect of the heat source, the thickness of the printed layers, the... Read More about Surface texture measurement for additive manufacturing.

Optical metrology for digital manufacturing: A review
Conference Proceeding
Catalucci, S., Thompson, A., Eastwood, J., Piano, S., Branson, D. T., & Leach, R. Optical metrology for digital manufacturing: A review.

The so-called 4th Industrial Revolution is defined by the transformation of individual manufacturing activities into interconnected, highly efficient, flexible, and automated production flows. In this context, manufacturing processes are moving from... Read More about Optical metrology for digital manufacturing: A review.

Laser ultrasound measurement of diaphragm thickness, Young’s modulus and Poisson’s ratio in a MEMS device
Journal Article
McKee, C., Culshaw, B., & Leach, R. K. (in press). Laser ultrasound measurement of diaphragm thickness, Young’s modulus and Poisson’s ratio in a MEMS device. IEEE Journal of Selected Topics in Quantum Electronics, https://doi.org/10.1109/JSTQE.2016.2635518

Laser-generated Lamb waves, coupled with a large bandwidth Michelson interferometer, have been demonstrated to accurately measure the thickness of a MEMS pressure sensor diaphragm in the [110] direction of a silicon wafer. Using the reassigned Gabor... Read More about Laser ultrasound measurement of diaphragm thickness, Young’s modulus and Poisson’s ratio in a MEMS device.