Proceedings of Spie the International Society For Optical Engineering, 2002
This paper describes the development of an optical method of phase measurement and further three-... more This paper describes the development of an optical method of phase measurement and further three-dimensional surface reconstruction using colored structured light. The paper investigates a new method for improving the measurement of three-dimensional shapes by using color information of the measured scene as an additional parameter. The general problems of the most widely used algorithms (phase shifting profilometry and Fourier fringe analysis) are that phase maps produced by these methods are wrapped, in some cases the acquired fringe pattern does not fill the field of view, there may be spatially isolated areas and there is often invalid and/or noisy data. This paper aims to demonstrate a new method for three- dimensional surface reconstruction using colored fringe patterns. The proposed technique uses colored fringe patterns, which are projected at different angles onto the measured scene. Shortcomings, which arise using standard methods, can be overcome using a color multichannel Fourier fringe technique.
In automotive and glass making industries, there is a need for accurately measuring the 3D shapes... more In automotive and glass making industries, there is a need for accurately measuring the 3D shapes of reflective surfaces to speed up and ensure product development and manufacturing quality by using non-contact techniques. This paper describes a technique for the measurement of non-full-field reflective surfaces of automotive glass by using a fringe reflection technique. Physical properties of the measurement surfaces do not allow us to apply optical geometries used in existing techniques for surface measurement based upon direct fringe pattern illumination. However, this property of surface reflectivity can be used to implement similar ideas from existing techniques in a new improved method. In other words, the reflective surface can be used as a mirror to reflect illuminated fringe patterns onto a screen behind. It has been found that in the case of implementing the reflective fringe technique, the phase-shift distribution depends not only on the height of the object but also on the slope at each measurement point. This requires the solving of differential equations to find the surface slope and height distributions in the x and y directions and development of the additional height reconstruction algorithms. The main focus has been made on developing a mathematical model of the optical sub-system and discussing ways for its practical implementation including calibration procedures. A number of implemented image processing algorithms for system calibration and data analysis are discussed and two experimental results are given for automotive glass surfaces with different shapes and defects. The proposed technique showed the ability to provide accurate non-destructive measurement of 3D shapes of the reflective automotive glass surfaces and can be used as a key element for a glass shape quality control system on-line or in a laboratory environment.
2011 18th IEEE International Conference on Image Processing, 2011
An investigation into orientation preferences shown by actin fibres within ex-situ actin as image... more An investigation into orientation preferences shown by actin fibres within ex-situ actin as imaged by Atomic Force Microscopy (AFM) is described. Actin is a primary cytoskeletal component and is believed to play a vital role in cell structure. Actin structure images measured by AFM were analysed using automated pre-processing steps. These steps were identical for the production of an initial
In this paper, we suggest a novel system that is capable of measuring absolute distances with an ... more In this paper, we suggest a novel system that is capable of measuring absolute distances with an uncertainty of one micrometer, or better, over a distance of up to 20 meters. This system consists of a Michelson interferometer, a tunable external cavity diode laser, a wavelength meter, a digital camera and a computer. The Michelson interferometer contains a reference arm mirror, a target arm mirror, a coherent light source, a white screen and a beam-splitter. The distance between the beam-splitter and the reference arm is known a priori with one-micrometer accuracy. The distance between the beam-splitter and the required measurement target arm is initially known with only a low precision accuracy of one-millimeter. The distance between the beam-splitter and the target arm is required to be measured with one micrometer uncertainty, or better. Index Terms— Absolute distance measurement, external cavity tunable diode laser, Fourier fringe analysis, Michelson interferometer, synthetic wa...
Tapping mode atomic force microscopy (AFM) provides phase images in addition to height and amplit... more Tapping mode atomic force microscopy (AFM) provides phase images in addition to height and amplitude images. Although the behavior of tapping mode AFM has been investigated using mathematical modeling, comprehensive understanding of the behavior of tapping mode AFM still poses a significant challenge to the AFM community, involving issues such as the correct interpretation of the phase images. In this paper, the cantilever's dynamic behavior in tapping mode AFM is studied through a three dimensional finite element method. The cantilever's dynamic displacement responses are firstly obtained via simulation under different tip-sample separations, and for different tip-sample interaction forces, such as elastic force, adhesion force, viscosity force, and the van der Waals force, which correspond to the cantilever's action upon various different representative computer-generated test samples. Simulated results show that the dynamic cantilever displacement response can be divi...
In this paper, a filtering technique based upon two-dimensional continuous wavelet transform (2D-... more In this paper, a filtering technique based upon two-dimensional continuous wavelet transform (2D-CWT) is used to eliminate the low frequency components of fringe patterns. The filtered fringe patterns are subsequently demodulated using a standard Fourier transform profilometry (FTP) algorithm. This image pre-filtering stage improves the noise performance of the FTP algorithm and enables the FTP method to demodulate fringe patterns with larger bandwidths. Also, the 2D-CWT technique reduces speckle noise significantly. Moreover, only a single fringe pattern is required in this technique. The 2D-CWT algorithm is capable of separating low frequency terms from the high frequency terms that contain phase-modulated fringe information, even when both interfere, greatly, in the frequency domain. The proposed algorithm is tested, both via computer simulation and using real fringe patterns. This revealed the robustness of this algorithm and also demonstrably enables the demodulation of a wider range of fringe patterns using the FTP technique. addresses: m.a.gdeisat@ljmu.ac.uk (M.A. Gdeisat), d.r.burton @ljmu.ac.uk (D.R. Burton), m.j.lalor@ljmu.ac.uk (M.J. Lalor). www.elsevier.com/locate/optcom Optics Communications 266 (2006) 482-489
The widest used algorithms for 3-D surface measurement using structured fringe patterns are phase... more The widest used algorithms for 3-D surface measurement using structured fringe patterns are phase stepping and Fourier fringe analysis. The techniques currently employed use mostly monochrome fringe patterns as a tool for phase information measurement and further surface reconstruction. However, the information contained in colour images is much more than that of monochrome, in this case, a new colour technique
International Conference on Medical Information Visualisation--BioMedical Visualisation (MedVis'06), 2006
Research into high performance surface measurement using continuously structured light projection... more Research into high performance surface measurement using continuously structured light projection and Fourier transform profilometry is described. It is shown that the capture of single-colour interferometer fringes, modulated by the surface variations of either test phantoms or human volunteers can yield body surface height maps in the high radiation environment of the radiotherapy clinic. The 3D surfaces are reconstructed from
Proceedings / ICIP ... International Conference on Image Processing
All atomic force microscope (AFM) images suffer from distortions, which are principally produced ... more All atomic force microscope (AFM) images suffer from distortions, which are principally produced by the interaction between the measured sample and the AFM tip. If the three-dimensional shape of the tip is known, the distorted image can be processed and the original surface form ‘restored’, typically by deconvolution approaches. This restored image gives a better representation of the real 3D surface of the measured sample than the original distorted image. In this paper, we propose a method for estimating the three-dimensional shape of the AFM tip by measuring a micro-cylinder with a-priori known dimensions. The estimated tip shape is then used to restore subsequent AFM images, when measured with the same tip, under similar measurement conditions. Significantly, the impulse response of the AFM can be deduced using this method. The suitability of this novel approach for restoring AFM images has been confirmed using both computer simulation and also with real experimental AFM images....
ABSTRACT The rapid, ultra-precision measurement of the shape of engineering components is becomin... more ABSTRACT The rapid, ultra-precision measurement of the shape of engineering components is becominc; a major requirement for today's quality conscious industries. This paper presents a technique for the reconstruction of surfaces underlying optically generated contour maps. The technique views the map as a constant spacing straight fringe pattern phase modulated by the underlying surface shape. The Fourier transform is used as a means of demodulating the pattern producing a 2π wrapped phase distribution. The conversion of this phase information to a range map is performed and so the surface is reconstructed. Methods for the quantitative analysis of the resulting map are discussed, including techniques based on differential geometric analysis, to yield data on items such as the first and second fundamental forms and hence functionally important criteria such as point surface principal curvature etc. The relationship which exists between the accuracy of these measurements and the nature of the demodulation filtering performed in the Fourier domain is briefly discussed.
ABSTRACT Recent work has shown the importance of the fast Fourier transform (FFT) in the automati... more ABSTRACT Recent work has shown the importance of the fast Fourier transform (FFT) in the automatic analysis of fringe patterns. Three problem areas are encountered when the FFT is used as an analysis tool in this fashion, namely, aliasing, the picket fence effect and leakage. The authors consider leakage to be by far the biggest problem in this application. The paper defines what causes leakage and suggests how leakage may be controlled using data weighting functions. Comparative results obtained using a variety of functions are presented.
Optical Measurement Systems for Industrial Inspection IV, 2005
In this paper, we propose a novel three-dimensional phase unwrapping algorithm that extends the &... more In this paper, we propose a novel three-dimensional phase unwrapping algorithm that extends the "two-dimensional phase unwrapping algorithm based on sorting by reliability following a non-continuous path" into three dimensions. The proposed algorithm depends on a quality map to unwrap the more reliable voxels first and the less reliable ones last. It follows a non-continuous path to perform the unwrapping
Microsystems Engineering: Metrology and Inspection III, 2003
ABSTRACT In high speed grinding research it is required to measure temperature within the workpie... more ABSTRACT In high speed grinding research it is required to measure temperature within the workpiece. Present techniques are thermocouple based, and often suffer from excessive electrical noise on the signal. This paper presents a number of novel fiber optic sensing devices that overcome this limitation and also offer greater performance. Optical fiber devices are simpler to place in situ prior to the machining tests and they offer faster response and greater sensitivity than was previously possible. Results are presented from machining tests and the new devices are compared with each other and previous techniques.
2000 IEEE Conference on Information Visualization. An International Conference on Computer Visualization and Graphics, 2000
A new method for outlining tumour volumes and surrounding organs from computed tomography slices ... more A new method for outlining tumour volumes and surrounding organs from computed tomography slices is presented. This task is performed during radiotherapy treatment planning and usually consists of the hand-drawing of a set of contours on the appropriate computed tomography slices of the patient lying in treatment position. This method is both time consuming and prone to errors. Our solution,
We present a novel system that can measure absolute distances of up to 300 mm with an uncertainty... more We present a novel system that can measure absolute distances of up to 300 mm with an uncertainty of the order of one micrometer, within a timeframe of 40 seconds. The proposed system uses a Michelson interferometer, a tunable laser, a wavelength meter and a computer for analysis. The principle of synthetic wave creation is used in a novel way in that the system employs an initial low precision estimate of the distance, obtained using a triangulation, or time-of-flight, laser system, or similar, and then iterates through a sequence of progressively smaller synthetic wavelengths until it reaches micrometer uncertainties in the determination of the distance. A further novel feature of the system is its use of Fourier transform phase analysis techniques to achieve sub-wavelength accuracy. This method has the major advantages of being relatively simple to realize, offering demonstrated high relative precisions better than 5 × 10(-5). Finally, the fact that this device does not require a continuous line-of-sight to the target as is the case with other configurations offers significant advantages.
Image Processing, IEEE International Conference, 2011
There has recently been a significant growth in interest in determining the mechanical properties... more There has recently been a significant growth in interest in determining the mechanical properties of living human cells. Much of this work has centred around the application of the Hertz Contact Stress model to force/displacement curves that are obtained from atomic force microscopy. However, it is widely recognised that the conventional Hertzian approach, that is based upon a linear elastic
2011 18th IEEE International Conference on Image Processing, 2011
The paper reports on a novel method for reconstruction of cellular features including cell nuclei... more The paper reports on a novel method for reconstruction of cellular features including cell nuclei and cellular boundaries from actin tagged fluorescence confocal microscopy images. Such reconstruction can provide spatial context for subsequent quantitative analysis of changes to actin organisation and cell morphology in both controlled and stressed cell cultures. The proposed method is fully automatic and is formulated within
Proceedings of Spie the International Society For Optical Engineering, 2002
This paper describes the development of an optical method of phase measurement and further three-... more This paper describes the development of an optical method of phase measurement and further three-dimensional surface reconstruction using colored structured light. The paper investigates a new method for improving the measurement of three-dimensional shapes by using color information of the measured scene as an additional parameter. The general problems of the most widely used algorithms (phase shifting profilometry and Fourier fringe analysis) are that phase maps produced by these methods are wrapped, in some cases the acquired fringe pattern does not fill the field of view, there may be spatially isolated areas and there is often invalid and/or noisy data. This paper aims to demonstrate a new method for three- dimensional surface reconstruction using colored fringe patterns. The proposed technique uses colored fringe patterns, which are projected at different angles onto the measured scene. Shortcomings, which arise using standard methods, can be overcome using a color multichannel Fourier fringe technique.
In automotive and glass making industries, there is a need for accurately measuring the 3D shapes... more In automotive and glass making industries, there is a need for accurately measuring the 3D shapes of reflective surfaces to speed up and ensure product development and manufacturing quality by using non-contact techniques. This paper describes a technique for the measurement of non-full-field reflective surfaces of automotive glass by using a fringe reflection technique. Physical properties of the measurement surfaces do not allow us to apply optical geometries used in existing techniques for surface measurement based upon direct fringe pattern illumination. However, this property of surface reflectivity can be used to implement similar ideas from existing techniques in a new improved method. In other words, the reflective surface can be used as a mirror to reflect illuminated fringe patterns onto a screen behind. It has been found that in the case of implementing the reflective fringe technique, the phase-shift distribution depends not only on the height of the object but also on the slope at each measurement point. This requires the solving of differential equations to find the surface slope and height distributions in the x and y directions and development of the additional height reconstruction algorithms. The main focus has been made on developing a mathematical model of the optical sub-system and discussing ways for its practical implementation including calibration procedures. A number of implemented image processing algorithms for system calibration and data analysis are discussed and two experimental results are given for automotive glass surfaces with different shapes and defects. The proposed technique showed the ability to provide accurate non-destructive measurement of 3D shapes of the reflective automotive glass surfaces and can be used as a key element for a glass shape quality control system on-line or in a laboratory environment.
2011 18th IEEE International Conference on Image Processing, 2011
An investigation into orientation preferences shown by actin fibres within ex-situ actin as image... more An investigation into orientation preferences shown by actin fibres within ex-situ actin as imaged by Atomic Force Microscopy (AFM) is described. Actin is a primary cytoskeletal component and is believed to play a vital role in cell structure. Actin structure images measured by AFM were analysed using automated pre-processing steps. These steps were identical for the production of an initial
In this paper, we suggest a novel system that is capable of measuring absolute distances with an ... more In this paper, we suggest a novel system that is capable of measuring absolute distances with an uncertainty of one micrometer, or better, over a distance of up to 20 meters. This system consists of a Michelson interferometer, a tunable external cavity diode laser, a wavelength meter, a digital camera and a computer. The Michelson interferometer contains a reference arm mirror, a target arm mirror, a coherent light source, a white screen and a beam-splitter. The distance between the beam-splitter and the reference arm is known a priori with one-micrometer accuracy. The distance between the beam-splitter and the required measurement target arm is initially known with only a low precision accuracy of one-millimeter. The distance between the beam-splitter and the target arm is required to be measured with one micrometer uncertainty, or better. Index Terms— Absolute distance measurement, external cavity tunable diode laser, Fourier fringe analysis, Michelson interferometer, synthetic wa...
Tapping mode atomic force microscopy (AFM) provides phase images in addition to height and amplit... more Tapping mode atomic force microscopy (AFM) provides phase images in addition to height and amplitude images. Although the behavior of tapping mode AFM has been investigated using mathematical modeling, comprehensive understanding of the behavior of tapping mode AFM still poses a significant challenge to the AFM community, involving issues such as the correct interpretation of the phase images. In this paper, the cantilever's dynamic behavior in tapping mode AFM is studied through a three dimensional finite element method. The cantilever's dynamic displacement responses are firstly obtained via simulation under different tip-sample separations, and for different tip-sample interaction forces, such as elastic force, adhesion force, viscosity force, and the van der Waals force, which correspond to the cantilever's action upon various different representative computer-generated test samples. Simulated results show that the dynamic cantilever displacement response can be divi...
In this paper, a filtering technique based upon two-dimensional continuous wavelet transform (2D-... more In this paper, a filtering technique based upon two-dimensional continuous wavelet transform (2D-CWT) is used to eliminate the low frequency components of fringe patterns. The filtered fringe patterns are subsequently demodulated using a standard Fourier transform profilometry (FTP) algorithm. This image pre-filtering stage improves the noise performance of the FTP algorithm and enables the FTP method to demodulate fringe patterns with larger bandwidths. Also, the 2D-CWT technique reduces speckle noise significantly. Moreover, only a single fringe pattern is required in this technique. The 2D-CWT algorithm is capable of separating low frequency terms from the high frequency terms that contain phase-modulated fringe information, even when both interfere, greatly, in the frequency domain. The proposed algorithm is tested, both via computer simulation and using real fringe patterns. This revealed the robustness of this algorithm and also demonstrably enables the demodulation of a wider range of fringe patterns using the FTP technique. addresses: m.a.gdeisat@ljmu.ac.uk (M.A. Gdeisat), d.r.burton @ljmu.ac.uk (D.R. Burton), m.j.lalor@ljmu.ac.uk (M.J. Lalor). www.elsevier.com/locate/optcom Optics Communications 266 (2006) 482-489
The widest used algorithms for 3-D surface measurement using structured fringe patterns are phase... more The widest used algorithms for 3-D surface measurement using structured fringe patterns are phase stepping and Fourier fringe analysis. The techniques currently employed use mostly monochrome fringe patterns as a tool for phase information measurement and further surface reconstruction. However, the information contained in colour images is much more than that of monochrome, in this case, a new colour technique
International Conference on Medical Information Visualisation--BioMedical Visualisation (MedVis'06), 2006
Research into high performance surface measurement using continuously structured light projection... more Research into high performance surface measurement using continuously structured light projection and Fourier transform profilometry is described. It is shown that the capture of single-colour interferometer fringes, modulated by the surface variations of either test phantoms or human volunteers can yield body surface height maps in the high radiation environment of the radiotherapy clinic. The 3D surfaces are reconstructed from
Proceedings / ICIP ... International Conference on Image Processing
All atomic force microscope (AFM) images suffer from distortions, which are principally produced ... more All atomic force microscope (AFM) images suffer from distortions, which are principally produced by the interaction between the measured sample and the AFM tip. If the three-dimensional shape of the tip is known, the distorted image can be processed and the original surface form ‘restored’, typically by deconvolution approaches. This restored image gives a better representation of the real 3D surface of the measured sample than the original distorted image. In this paper, we propose a method for estimating the three-dimensional shape of the AFM tip by measuring a micro-cylinder with a-priori known dimensions. The estimated tip shape is then used to restore subsequent AFM images, when measured with the same tip, under similar measurement conditions. Significantly, the impulse response of the AFM can be deduced using this method. The suitability of this novel approach for restoring AFM images has been confirmed using both computer simulation and also with real experimental AFM images....
ABSTRACT The rapid, ultra-precision measurement of the shape of engineering components is becomin... more ABSTRACT The rapid, ultra-precision measurement of the shape of engineering components is becominc; a major requirement for today's quality conscious industries. This paper presents a technique for the reconstruction of surfaces underlying optically generated contour maps. The technique views the map as a constant spacing straight fringe pattern phase modulated by the underlying surface shape. The Fourier transform is used as a means of demodulating the pattern producing a 2π wrapped phase distribution. The conversion of this phase information to a range map is performed and so the surface is reconstructed. Methods for the quantitative analysis of the resulting map are discussed, including techniques based on differential geometric analysis, to yield data on items such as the first and second fundamental forms and hence functionally important criteria such as point surface principal curvature etc. The relationship which exists between the accuracy of these measurements and the nature of the demodulation filtering performed in the Fourier domain is briefly discussed.
ABSTRACT Recent work has shown the importance of the fast Fourier transform (FFT) in the automati... more ABSTRACT Recent work has shown the importance of the fast Fourier transform (FFT) in the automatic analysis of fringe patterns. Three problem areas are encountered when the FFT is used as an analysis tool in this fashion, namely, aliasing, the picket fence effect and leakage. The authors consider leakage to be by far the biggest problem in this application. The paper defines what causes leakage and suggests how leakage may be controlled using data weighting functions. Comparative results obtained using a variety of functions are presented.
Optical Measurement Systems for Industrial Inspection IV, 2005
In this paper, we propose a novel three-dimensional phase unwrapping algorithm that extends the &... more In this paper, we propose a novel three-dimensional phase unwrapping algorithm that extends the "two-dimensional phase unwrapping algorithm based on sorting by reliability following a non-continuous path" into three dimensions. The proposed algorithm depends on a quality map to unwrap the more reliable voxels first and the less reliable ones last. It follows a non-continuous path to perform the unwrapping
Microsystems Engineering: Metrology and Inspection III, 2003
ABSTRACT In high speed grinding research it is required to measure temperature within the workpie... more ABSTRACT In high speed grinding research it is required to measure temperature within the workpiece. Present techniques are thermocouple based, and often suffer from excessive electrical noise on the signal. This paper presents a number of novel fiber optic sensing devices that overcome this limitation and also offer greater performance. Optical fiber devices are simpler to place in situ prior to the machining tests and they offer faster response and greater sensitivity than was previously possible. Results are presented from machining tests and the new devices are compared with each other and previous techniques.
2000 IEEE Conference on Information Visualization. An International Conference on Computer Visualization and Graphics, 2000
A new method for outlining tumour volumes and surrounding organs from computed tomography slices ... more A new method for outlining tumour volumes and surrounding organs from computed tomography slices is presented. This task is performed during radiotherapy treatment planning and usually consists of the hand-drawing of a set of contours on the appropriate computed tomography slices of the patient lying in treatment position. This method is both time consuming and prone to errors. Our solution,
We present a novel system that can measure absolute distances of up to 300 mm with an uncertainty... more We present a novel system that can measure absolute distances of up to 300 mm with an uncertainty of the order of one micrometer, within a timeframe of 40 seconds. The proposed system uses a Michelson interferometer, a tunable laser, a wavelength meter and a computer for analysis. The principle of synthetic wave creation is used in a novel way in that the system employs an initial low precision estimate of the distance, obtained using a triangulation, or time-of-flight, laser system, or similar, and then iterates through a sequence of progressively smaller synthetic wavelengths until it reaches micrometer uncertainties in the determination of the distance. A further novel feature of the system is its use of Fourier transform phase analysis techniques to achieve sub-wavelength accuracy. This method has the major advantages of being relatively simple to realize, offering demonstrated high relative precisions better than 5 × 10(-5). Finally, the fact that this device does not require a continuous line-of-sight to the target as is the case with other configurations offers significant advantages.
Image Processing, IEEE International Conference, 2011
There has recently been a significant growth in interest in determining the mechanical properties... more There has recently been a significant growth in interest in determining the mechanical properties of living human cells. Much of this work has centred around the application of the Hertz Contact Stress model to force/displacement curves that are obtained from atomic force microscopy. However, it is widely recognised that the conventional Hertzian approach, that is based upon a linear elastic
2011 18th IEEE International Conference on Image Processing, 2011
The paper reports on a novel method for reconstruction of cellular features including cell nuclei... more The paper reports on a novel method for reconstruction of cellular features including cell nuclei and cellular boundaries from actin tagged fluorescence confocal microscopy images. Such reconstruction can provide spatial context for subsequent quantitative analysis of changes to actin organisation and cell morphology in both controlled and stressed cell cultures. The proposed method is fully automatic and is formulated within
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Papers by David Burton