ITEE Ph.D confirmation seminar: Ben Appleton, 11.00AM, Tue 11 Mar 2003
Image Segmentation
Speaker: Ben Appleton, ITEE
When: 11.00AM, Tuesday 11 Mar 2003
Venue: 78-622
Host: Associate Professor Brian Lovell
Abstract:
Segmentation is the fundamental first step toward analysing and understanding images. It may be defined as decomposing the image into its constituent parts, extracting the location and outline of objects of interest in an image. However the definition of an "interesting object" is dependent both upon the application and the image modality. Additionally, many applications demand speed at the expense of accuracy. As a result there is a wide spectrum of segmentation methods, each suited to a subset of segmentation problems and application environments. In this thesis we focus on segmentation problems presented by biomedical data. We consider planar data acquired by x-ray, ultrasound and optical microscopy, as well as volumetric and time-series data from Magnetic Resonance and Computed Tomography images. Biomedical data is characterised by high geometric variation both within and between patients or samples. Organs deform between observations due to physiological changes or simple displacement, cells grow and split, and often we are searching for pathological instances which by their very nature defy classification. In many cases even human experts differ in their judgement of a good segmentation. Despite the bleak outlook, it is these difficulties which are being overcome at the forefront of medical image segmentation. We will investigate a class of segmentation methods suited to many biomedical image analysis problems. These geometric optimisation methods are designed to use minimal structural information, instead aiming to find coherent curvilinear features which are deemed likely to be the boundary of an object of interest. Commonly known as active contours, they include the discrete active contours, snakes and level sets. Of particular interest is the geodesic active contour, which has been shown to give reliable segmentation results. We build on previous work in geodesic active contours to give optimal solutions to the associated minimisation problem, producing an algorithm that is significantly more robust and accurate on a range of segmentation problems. We also extend the geodesic active contour to extract open and closed geodesics in spaces with tensor-valued metrics.
Biography:
Ben Appleton is currently undertaking a PhD in the area of Image Analysis at the University of Queensland, Brisbane, Australia. He received his bachelor degrees in Science and Electrical Engineering from the University of Queensland in 2001. His research interests include active contours and energy minimisation algorithms.
Type:
Ph.D confirmation
Contact:
Associate Professor Brian Lovell, seminar host (lovell@itee.uq.edu.au)
or Guido Governatori (ITEE seminar co-ordinator)
(guido@itee.uq.edu.au)
ITEE seminar web page: http://www.itee.uq.edu.au/~seminar
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