Binary object recognition system on FPGA with bSOM

Tri-state Self Organizing Map (bSOM), which takes binary inputs and maintains tri-state weights, has been used for classification rather than clustering in this paper. The major contribution here is the demonstration of the potential use of the modified bSOM in security surveillance, as a recognition system on FPGA

Photometric study of the IC 65 group of galaxies

We carry out a photometric study of a poor group of late-type galaxies around IC 65, with the aim: (a) to search for new dwarf members and to measure their photometric characteristics; (b) to search for possible effects of mutual interactions on the morphology and star-formation characteristics of luminous and faint group members; (c) to evaluate the evolutionary status of this particular group. We make use of our BRI CCD observations, DPOSS blue and red frames, and the 2MASS JHK frames. In addition, we use the HI imaging data, the far-infrared and radio data from the literature. Search for dwarf galaxies is made using the SExtractor software. Detailed surface photometry is performed with the MIDAS package. Four LSB galaxies were classified as probable dwarf members of the group and the BRI physical and model parameters were derived for the first time for all true and probable group members. Newly found dIrr galaxies around the IC 65 contain a number of H II regions, which show a range of ages and propagating star-formation. Mildly disturbed gaseous and/or stellar morphology is found in several group members. Various structural, dynamical, and star-forming characteristics let us conclude that the IC 65 group is a typical poor assembly of late-type galaxies at an early stage of its dynamical evolution with some evidence of intragroup (tidal) interactions.Comment: 21 pages, 16 figures, submitted to A&

Dynamic texture recognition using time-causal and time-recursive spatio-temporal receptive fields

This work presents a first evaluation of using spatio-temporal receptive fields from a recently proposed time-causal spatio-temporal scale-space framework as primitives for video analysis. We propose a new family of video descriptors based on regional statistics of spatio-temporal receptive field responses and evaluate this approach on the problem of dynamic texture recognition. Our approach generalises a previously used method, based on joint histograms of receptive field responses, from the spatial to the spatio-temporal domain and from object recognition to dynamic texture recognition. The time-recursive formulation enables computationally efficient time-causal recognition. The experimental evaluation demonstrates competitive performance compared to state-of-the-art. Especially, it is shown that binary versions of our dynamic texture descriptors achieve improved performance compared to a large range of similar methods using different primitives either handcrafted or learned from data. Further, our qualitative and quantitative investigation into parameter choices and the use of different sets of receptive fields highlights the robustness and flexibility of our approach. Together, these results support the descriptive power of this family of time-causal spatio-temporal receptive fields, validate our approach for dynamic texture recognition and point towards the possibility of designing a range of video analysis methods based on these new time-causal spatio-temporal primitives.Comment: 29 pages, 16 figure

Methods for Analysing Endothelial Cell Shape and Behaviour in Relation to the Focal Nature of Atherosclerosis

The aim of this thesis is to develop automated methods for the analysis of the spatial patterns, and the functional behaviour of endothelial cells, viewed under microscopy, with applications to the understanding of atherosclerosis. Initially, a radial search approach to segmentation was attempted in order to trace the cell and nuclei boundaries using a maximum likelihood algorithm; it was found inadequate to detect the weak cell boundaries present in the available data. A parametric cell shape model was then introduced to fit an equivalent ellipse to the cell boundary by matching phase-invariant orientation fields of the image and a candidate cell shape. This approach succeeded on good quality images, but failed on images with weak cell boundaries. Finally, a support vector machines based method, relying on a rich set of visual features, and a small but high quality training dataset, was found to work well on large numbers of cells even in the presence of strong intensity variations and imaging noise. Using the segmentation results, several standard shear-stress dependent parameters of cell morphology were studied, and evidence for similar behaviour in some cell shape parameters was obtained in in-vivo cells and their nuclei. Nuclear and cell orientations around immature and mature aortas were broadly similar, suggesting that the pattern of flow direction near the wall stayed approximately constant with age. The relation was less strong for the cell and nuclear length-to-width ratios. Two novel shape analysis approaches were attempted to find other properties of cell shape which could be used to annotate or characterise patterns, since a wide variability in cell and nuclear shapes was observed which did not appear to fit the standard parameterisations. Although no firm conclusions can yet be drawn, the work lays the foundation for future studies of cell morphology. To draw inferences about patterns in the functional response of cells to flow, which may play a role in the progression of disease, single-cell analysis was performed using calcium sensitive florescence probes. Calcium transient rates were found to change with flow, but more importantly, local patterns of synchronisation in multi-cellular groups were discernable and appear to change with flow. The patterns suggest a new functional mechanism in flow-mediation of cell-cell calcium signalling

Controlling motile disclinations in a thick nematogenic material with an electric field

Manipulating topological disclination networks that arise in a symmetry-breaking phase transfor- mation in widely varied systems including anisotropic materials can potentially lead to the design of novel materials like conductive microwires, self-assembled resonators, and active anisotropic matter. However, progress in this direction is hindered by a lack of control of the kinetics and microstructure due to inherent complexity arising from competing energy and topology. We have studied thermal and electrokinetic effects on disclinations in a three-dimensional nonabsorbing nematic material with a positive and negative sign of the dielectric anisotropy. The electric flux lines are highly non-uniform in uniaxial media after an electric field below the Fr\'eedericksz threshold is switched on, and the kinetics of the disclination lines is slowed down. In biaxial media, depending on the sign of the dielectric anisotropy, apart from the slowing down of the disclination kinetics, a non-uniform electric field filters out disclinations of different topology by inducing a kinetic asymmetry. These results enhance the current understanding of forced disclination networks and establish the pre- sented method, which we call fluctuating electronematics, as a potentially useful tool for designing materials with novel properties in silico.Comment: 17 Pages, 14 Figure

A Bag of Features Based Approach for Classification of Motile Sperm Cells

The analysis of sperm morphology remains an essential process for diagnosis and treatment of male infertility. In this paper, a novel framework based on image processing is proposed to classify sperm cell images affected by noise due to their movement. This represents a challenge, articularly because the cells are not fixed or stained. The proposed framework is based on Speeded-Up Robust Features (SURF) combined with Bag of Features (BoF) models to quantise features computed by SURF. Support Vector Machines (SVMs) are used to classify the simplified feature vectors, extracted from sperm cell images, into normal, abnormal and noncell categories. The performance of this framework is compared to a similar model where the Histogram of Oriented Gradients (HOG) is used to extract features and SVMs is applied for their classification. The proposed framework allows to achieve classification results with an average accuracy of 90% with the SURF approach compared to 78% with the HOG approach

Global Properties of the Rich Cluster ABCG 209 at z~0.2. Spectroscopic and Photometric Catalogue

This paper is aimed at giving an overview of the global properties of the rich cluster of galaxies ABCG 209. This is achieved by complementing the already available data with new medium resolution spectroscopy and NIR photometry which allow us to i) analyse in detail the cluster dynamics, distinguishing among galaxies belonging to different substructures and deriving their individual velocity distributions, using a total sample of 148 galaxies in the cluster region, of which 134 belonging to the cluster; ii) derive the cluster NIR luminosity function; iii) study the Kormendy relation and the photometric plane of cluster early-type galaxies (ETGs). Finally we provide an extensive photometric (optical and NIR) and spectroscopic dataset for such a complex system to be used in further analyses investigating the nature, formation and evolution of rich clusters of galaxies. The observational scenario confirms that ABCG 209 is presently undergoing strong dynamical evolution with the merging of two or more subclumps. This interpretation is also supported by the detection of a radio halo (Giovannini et al. 2006) suggesting that there is a recent or ongoing merging. Cluster ETGs follow a Kormendy relation whose slope is consistent with previous studies both at optical and NIR wavelengths. We investigate the origin of the intrinsic scatter of the photometric plane due to trends of stellar populations, using line indices as indicators of age, metallicity and alpha/Fe enhancement. We find that the chemical evolution of galaxies could be responsible for the intrinsic dispersion of the Photometric Plane.Comment: 39 pages, 17 figures, MNRAS in pres

Interactive real-time three-dimensional visualisation of virtual textiles

Virtual textile databases provide a cost-efficient alternative to the use of existing hardcover sample catalogues. By taking advantage of the high performance features offered by the latest generation of programmable graphics accelerator boards, it is possible to combine photometric stereo methods with 3D visualisation methods to implement a virtual textile database. In this thesis, we investigate and combine rotation invariant texture retrieval with interactive visualisation techniques. We use a 3D surface representation that is a generic data representation that allows us to combine real-time interactive 3D visualisation methods with present day texture retrieval methods. We begin by investigating the most suitable data format for the 3D surface representation and identify relief-mapping combined with Bézier surfaces as the most suitable 3D surface representations for our needs, and go on to describe how these representation can be combined for real-time rendering. We then investigate ten different methods of implementing rotation invariant texture retrieval using feature vectors. These results show that first order statistics in the form of histogram data are very effective for discriminating colour albedo information, while rotation invariant gradient maps are effective for distinguishing between different types of micro-geometry using either first or second order statistics.Engineering and physical Sciences Research (EPSRC