Modelling and extracting periodically deforming objects by continuous, spatio-temporal shape description

This thesis proposes a new model for describing spatio-temporally deforming objects. Through a novel use of Fourier descriptors, it is shown how arbitrary shape description can be extended to include spatio-temporal shape deformation. It is further demonstrated that these new spatio-temporal Fourier descriptors have the ability to be used as the basis for both the recognition and extraction of deforming objects. Application of this new recognition technique to human gait sequences demonstrates recognition rates of over 86% for individual human subjects, signifying that these descriptors possess unique descriptive properties. Based upon the new spatio-temporal Fourier descriptor model, a new technique for the detection and extraction of deforming shapes from an image sequence is presented through a new variant of the Hough transform (the Continuous Deformable Hough Transform) that utilises spatio-temporal shape correlation within an evidence-gathering context. This new technique demonstrates excellent success rates and tolerance to noise, correctly extracting human subjects in image sequences corrupted with noise levels of up to 80%. The technique is also tested extensively using real-world data, thus demonstrating its worth in a modern-day computer vision system. Both the spatio-temporal Fourier descriptor model, the Continuous Deformable Hough Transform, and aspects of their application are fully discussed throughout the thesis, along with ideas and suggestions for future research and development.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Modelling and extracting periodically deforming objects by continuous, spatio-temporal shape description

This thesis proposes a new model for describing spatio-temporally deforming objects. Through a novel use of Fourier descriptors, it is shown how arbitrary shape description can be extended to include spatio-temporal shape deformation. It is further demonstrated that these new spatio-temporal Fourier descriptors have the ability to be used as the basis for both the recognition and extraction of deforming objects. Application of this new recognition technique to human gait sequences demonstrates recognition rates of over 86% for individual human subjects, signifying that these descriptors possess unique descriptive properties. Based upon the new spatio-temporal Fourier descriptor model, a new technique for the detection and extraction of deforming shapes from an image sequence is presented through a new variant of the Hough transform (the Continuous Deformable Hough Transform) that utilises spatio-temporal shape correlation within an evidence-gathering context. This new technique demonstrates excellent success rates and tolerance to noise, correctly extracting human subjects in image sequences corrupted with noise levels of up to 80%. The technique is also tested extensively using real-world data, thus demonstrating its worth in a modern-day computer vision system. Both the spatio-temporal Fourier descriptor model, the Continuous Deformable Hough Transform, and aspects of their application are fully discussed throughout the thesis, along with ideas and suggestions for future research and development.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Exploring Written Artefacts

This collection, presented to Michael Friedrich in honour of his academic career at of the Centre for the Study of Manuscript Cultures, traces key concepts that scholars associated with the Centre have developed and refined for the systematic study of manuscript cultures. At the same time, the contributions showcase the possibilities of expanding the traditional subject of ‘manuscripts’ to the larger perspective of ‘written artefacts’

Applied AI/ML for automatic customisation of medical implants

Most knee replacement surgeries are performed using ‘off-the-shelf’ implants, supplied with a set number of standardised sizes. X-rays are taken during pre-operative assessment and used by clinicians to estimate the best options for patients. Manual templating and implant size selection have, however, been shown to be inaccurate, and frequently the generically shaped products do not adequately fit patients’ unique anatomies. Furthermore, off-the-shelf implants are typically made from solid metal and do not exhibit mechanical properties like the native bone. Consequently, the combination of these factors often leads to poor outcomes for patients. Various solutions have been outlined in the literature for customising the size, shape, and stiffness of implants for the specific needs of individuals. Such designs can be fabricated via additive manufacturing which enables bespoke and intricate geometries to be produced in biocompatible materials. Despite this, all customisation solutions identified required some level of manual input to segment image files, identify anatomical features, and/or drive design software. These tasks are time consuming, expensive, and require trained resource. Almost all currently available solutions also require CT imaging, which adds further expense, incurs high levels of potentially harmful radiation, and is not as commonly accessible as X-ray imaging. This thesis explores how various levels of knee replacement customisation can be completed automatically by applying artificial intelligence, machine learning and statistical methods. The principal output is a software application, believed to be the first true ‘mass-customisation’ solution. The software is compatible with both 2D X-ray and 3D CT data and enables fully automatic and accurate implant size prediction, shape customisation and stiffness matching. It is therefore seen to address the key limitations associated with current implant customisation solutions and will hopefully enable the benefits of customisation to be more widely accessible.Open Acces

Exploring Written Artefacts

This collection, presented to Michael Friedrich in honour of his academic career at of the Centre for the Study of Manuscript Cultures, traces key concepts that scholars associated with the Centre have developed and refined for the systematic study of manuscript cultures. At the same time, the contributions showcase the possibilities of expanding the traditional subject of ‘manuscripts’ to the larger perspective of ‘written artefacts’

Photonic devices for sensing and security applications

The main aim of this thesis is the numerical and experimental verification of structured micro- and nano-scaled optical devices fabricated with e-beam, photolithography, reactive ion etching and embossing. Two separate themes were addressed; sensing of electromagnetic pulses by electro-optic non-linear guided wave photonic devices and free space photonic devices for security and anti-counterfeiting in polymer banknotes. The first theme was led by a comparison between two photonic devices used as extrinsic fibre optic sensors for the detection of short duration electromagnetic pulses (EMPs). A suitable electro-optic substrate was used for the fabrication of both micron sized waveguide-based evanescent coupling photonic devices, modelled using beam envelope methods, and its nano-structured surface Plasmon enhanced counterpart, modelled using FDTD. Both devices are capable of detecting EMPs with field strengths ranging from 50 – 500kV/m with pulse durations from 200ns – 2000ns. The surface enhanced plasmonic device showed improved device sensitivity and tunability, with a more linearized response along with greater ease of integration with optical fibres. In the second theme the photonic devices were used for image formation through diffractive optical methods with a view to polymeric mass replication. Multilevel 2μm - 8μm feature size diffractive optical elements, designed for dual colour operation in the scalar domain, were compared to 250nm feature size binary phase modulated Bragg gratings for single colour operation in the resonance domain. Both devices are capable of generating high fidelity images under appropriate illumination. The scalar domain elements, designed for 450nm and 650nm illumination, showed measured diffraction efficiencies of 37% and 55% in the 0th order for each of the respective illumination wavelengths. Operating at 532nm, the diffraction efficiency of the resonance domain element was measured to be 70%. The resonance domain element is significantly shallower than the scalar domain device with a reduced number of phase levels (2 compared to 16). With the final aim of this application area being replication on a flexible base substrate, the elements with larger feature sizes would represent challenging replication process (in terms of linearization of depth profile) whereas the smaller feature sizes would be more challenging in lateral dimensions. In both cases the potential for counterfeiting would be reduced and the addition of a second image at a different illumination wavelength for the scalar domain element would lead to a further enhanced degree of security

Raman microscopic and computational studies of artists' pigments and molecular inorganic compounds

This thesis is principally concerned with spectroscopic and computational studies of artists' pigments. Manuscripts, art and archaeological artefacts were examined by Raman microscopy, identifying the pigments and drawing conclusions for historical and conservation purposes. Studies of Anglo Saxon and later manuscripts have shown the Insular palette triumvirate, assumed to be orpiment, red lead and verdigris, to contain red ochre and vergaut, but no verdigris. This remains unchanged until the introduction of lazurite in C.920 AD and vermilion in the 12th century. Lazurite has been erroneously identified on the Lindisfarne Gospels, by the technique of Roosen-Runge. Raman microscopy shows the blue pigments to be exclusively indigo, casting doubt on analyses performed using Roosen-Runge's technique. The Islamic manuscript palette was found to be remarkably consistent across a substantial geographical area over an extended period. It is also very similar to that of early Western manuscripts. Comparison of these results with existing literary sources has shown the latter to be highly inaccurate. The palette of William Blake was examined and compared to results of analysis by False Colour Infrared Photography (FC-IP). The FC-IP technique was determined to be inappropriate for pigment identification. Two significant artefacts were shown to be modern forgeries: a rare Assyrian fresco contains a modern green pigment, and the world famous Vinland map was found to have significant quantities of anatase in the yellow lines. Density Functional Theory methods were applied to the mechanism of decay isomerisation of AS4S4, which was partially clarified, and to the geometries of R2SeX2 (R = CF3, CF2H, CFH2, CH3, CH2CH3, CH(CH3)2, t-Butyl, X = F, Cl, Br, I, At). The most stable geometry was found to be determined by the polarity of the Se-X bonds and the steric and electron-withdrawal effects of the R-group on the C-Se bond strength

Entropy in Image Analysis II

Image analysis is a fundamental task for any application where extracting information from images is required. The analysis requires highly sophisticated numerical and analytical methods, particularly for those applications in medicine, security, and other fields where the results of the processing consist of data of vital importance. This fact is evident from all the articles composing the Special Issue "Entropy in Image Analysis II", in which the authors used widely tested methods to verify their results. In the process of reading the present volume, the reader will appreciate the richness of their methods and applications, in particular for medical imaging and image security, and a remarkable cross-fertilization among the proposed research areas