Skip to main content

Research Repository

Advanced Search

All Outputs (126)

Uncertainty evaluation of fringe projection based on the linear systems theory
Presentation / Conference Contribution
Gayton, G., Su, R., Leach, R., & Bradley, L. (2019, July). Uncertainty evaluation of fringe projection based on the linear systems theory. Presented at 35th Annual Coordinate Metrology Society Conference, Orlando, Florida

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.

Tolerance on sphere radius for the calibration of the transfer function of coherence scanning interferometry
Presentation / Conference Contribution
Su, R., Coupland, J. M., Wang, Y., & Leach, R. K. (2017, June). Tolerance on sphere radius for the calibration of the transfer function of coherence scanning interferometry. Presented at SPIE Optical Metrology, Munich, Germany

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.

Modelling of coherence scanning interferometry for complex surfaces based on a boundary element method
Presentation / Conference Contribution
Thomas, M., Su, R., Nikolaev, N., Coupland, J., & Leach, R. (2019, June). Modelling of coherence scanning interferometry for complex surfaces based on a boundary element method. Presented at Modeling Aspects in Optical Metrology VII, Munich, Germany

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.

Imaging beyond the fundamental slope limit in surface metrology using fluorophore-aided scattering microscopy
Presentation / Conference Contribution
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, Paris, France

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.

Automated assessment of object coverage in smart, optical form measurement
Presentation / Conference Contribution
Catalucci, S., Senin, N., Stavroulakis, P., & Leach, R. (2019, June). Automated assessment of object coverage in smart, optical form measurement. Presented at 19th International euspen Conference & Exhibition, Bilbao, Spain

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.

All-optical difference engine for in-process defect inspection for roll-to-roll printed electronics
Presentation / Conference Contribution
Feng, X., Su, R., Happonen, T., Liu, J., & Leach, R. (2018, August). All-optical difference engine for in-process defect inspection for roll-to-roll printed electronics. Presented at 10th International Symposium on Precision Engineering Measurements and Instrumentation (ISPEMI 2018), Kunming, China

© 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.

High-accuracy surface measurement through modelling of the surface transfer function in interference microscopy
Presentation / Conference Contribution
Su, R., Thomas, M., Liu, M., Coupland, J., & Leach, R. (2019, August). High-accuracy surface measurement through modelling of the surface transfer function in interference microscopy. Presented at Applied Optical Metrology III, San Diego, United States

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
Presentation / Conference Contribution
de Groot, P. J., Colonna de Lega, X., Su, R., & Leach, R. K. (2019, August). Does interferometry work? A critical look at the foundations of interferometric surface topography measurement. Presented at Applied Optical Metrology III, San Diego, United States

© 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.

Modelling Fringe Projection Based on Linear Systems Theory and Geometric Transformation
Presentation / Conference Contribution
Gayton, G., Su, R., & Leach, R. (2019, September). Modelling Fringe Projection Based on Linear Systems Theory and Geometric Transformation. Presented at 14th International Symposium on Measurement Technology and Intelligent Instruments (ISMTII2019), Niigata, Japan

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.

Automated characterisation of multi-view fringe projection system for three- dimensional measurement of additively manufactured parts
Presentation / Conference Contribution
Leach, R. K., Shaheen, A., Piano, S., Sims-Waterhouse, D., & Bointon, P. (2019, September). Automated characterisation of multi-view fringe projection system for three- dimensional measurement of additively manufactured parts. Presented at Special Interest Group Meeting: Advancing Precision in Additive Manufacturing, Ecole Centrale de Nantes, Nantes, France

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.

Cascaded machine learning model for reconstruction of surface topography from light scattering
Presentation / Conference Contribution
Liu, M., Senin, N., Su, R., & Leach, R. Cascaded machine learning model for reconstruction of surface topography from light scattering. Presented at Optics and Photonics for Advanced Dimensional Metrology, Online Only, France

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.

Optical topography measurement of steeply-sloped surfaces beyond the specular numerical aperture limit
Presentation / Conference Contribution
Thomas, M., Su, R., de Groot, P., & Leach, R. Optical topography measurement of steeply-sloped surfaces beyond the specular numerical aperture limit. Presented at Optics and Photonics for Advanced Dimensional Metrology, Online Only, France

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.

Fourier optics modelling of coherence scanning interferometers
Presentation / Conference Contribution
de Groot, P. J., Colonna de Lega, X., Su, R., Coupland, J., & Leach, R. K. (2021, August). Fourier optics modelling of coherence scanning interferometers. Presented at Applied Optical Metrology IV, San Diego, United States

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.

Automated assessment of measurement quality in optical coordinate metrology of complex freeform parts
Presentation / Conference Contribution
Catalucci, S., Senin, N., Piano, S., & Leach, R. (2021, June). Automated assessment of measurement quality in optical coordinate metrology of complex freeform parts. Presented at 21st International euspen Conference and Exhibition, Virtual

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.

Frequency scanning interferometry for accurate robot position measurement
Presentation / Conference Contribution
Isa, M. A., Khanesar, M. A., Leach, R., Branson, D., & Piano, S. (2022, May). Frequency scanning interferometry for accurate robot position measurement. Presented at 22nd International Conference & Exhibition, Geneva, Switzerland

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.

Quantifying the validity conditions of the Beckmann-Kirchhoff scattering model
Presentation / Conference Contribution
Hooshmand, H., Liu, M., Leach, R., & Piano, S. (2022, August). Quantifying the validity conditions of the Beckmann-Kirchhoff scattering model. Presented at SPIE Optical Engineering + Applications 2022, San Diego, California, United States

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.