Barry T. Thomas

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Many image-database retr-ieual systems rely heavily on the success oj one-shot queries, using optimised jemkre set-s to obtain the best possible results. What is ojten missing jt-om this appToach is acceptance oj the fact that the user knows considerably mor-e about the query being made than cm. be conveyed in szch Relatively simple terms. Ij the query(More)
After segmenting candidate exudates regions in colour retinal images we present and compare two methods for their classification. The Neural Network based approach performs marginally better than the Support Vector Machine based approach, but we show that the latter are more flexible given criteria such as control of sensitivity and specificity rates. We(More)
The location of the optic disc is of critical importance in retinal image analysis. In this work we improve on an approach introduced in [3] who localised an optic disc region through greylevel morphology followed by snake fitting. We propose and implement both the automatic initialisation of the snake and the application of morphology in colour space. We(More)
Retinal exudates are typically manifested as spatially random yellow/white patches of varying sizes and shapes. They are a characteristic feature of retinal diseases such as diabetic maculopathy. An automatic method for the detection of exudate regions is introduced comprising image colour normalisation, enhancing the contrast between the objects and(More)
The process of shot break detection is a fundamental component in automatic video indexing, editing and archiving. This paper introduces a novel approach to the detection and classification of shot transitions in video sequences including cuts, fades and dissolves. It uses the average inter-frame correlation coefficient and block-based motion estimation to(More)
The process of shot break detection is a fundamental component in automatic video indexing, editing and archiving. This paper introduces a novel approach to the detection and classification of shot transitions in video sequences including cuts, fades and dissolves. It uses the average interframe correlation coefficient and block-based motion estimation to(More)
Image segmentation is the first stage of processing in many practical computer vision systems. While development of particular segmentation algorithms has attracted considerable research interest, relatively little work has been published on the subject of their evaluation. In this paper we propose a framework for quantitative evaluation of segmentation(More)
The problem of navigating a robot along a road is approached by means of creating and updating a simple representation of the road from a sequence of images. The representation chosen is a 4-parameter model that describes the width, direction and simple curvature of the road in a vehicle centred (X,Y,Z) world coordinate system. The model is created from(More)
Retinal exudates are a characteristic feature of many retinal diseases such as Diabetic Retinopathy. We address the development of a method to quantitatively diagnose these random yellow patches in colour retinal images automatically. After a colour normalisation and contrast enhancement preprocessing step, the colour retinal image is segmented using Fuzzy(More)