All Outputs (120)

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.

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.

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.