All Outputs (94)

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.