Basser Seminar Series

Line detection in a paracatadioptric image

Speaker: Prof Stephen Maybank

Time: Friday 20 April 2012, 4:00-5:00pm
Location: The University of Sydney, School of IT Building, Lecture Theatre (Room 123), Level 1

Abstract

In a central paracatadioptric imaging system a perspective camera takes an image of a scene reflected in a paraboloidal mirror. A 360 degree field of view is obtained, but the image is severely distorted. In particular, straight lines in the scene project to circles in the image. These distortions make it difficult to detect projected lines using standard image processing algorithms. The distortions are removed using a Fisher-Rao metric which is defined on the space of projected lines in the paracatadioptric image. The space of projected lines is divided into subsets such that on each subset the Fisher-Rao metric is closely approximated by the Euclidean metric. Each subset is sampled at the vertices of a square grid and values are assigned to the sampled points using an adaptation of the trace transform. The result is a set of digital images to which standard image processing algorithms can be applied. In particular, The task of line detection is reduced to the task of finding isolated peaks in a Sobel image. Experimental results are shown.

Speaker's biography

Stephen J. Maybank received the BA degree in mathematics from King’s College Cambridge in 1976 and the PhD degree in computer science from Birkbeck College, University of London in 1988. He was a research scientist at GEC from 1980 to 1995, first at MCCS, Frimley, and then, from 1989, at the GEC Marconi Hirst Research Centre in London. In 1995, he became a lecturer in the Department of Computer Science at the University of Reading and, in 2004, he became a professor in the School of Computer Science and Information Systems at Birkbeck College, University of London. His research interests include camera calibration, visual surveillance, tracking, filtering, applications of projective geometry to computer vision and applications of probability, statistics, and information theory to computer vision. He is the author of more than 120 scientific publications and one book. He is a Fellow of the IEEE and a Fellow of the Royal Statistical Sciety. He received the Koenderink Prize in 2008. For further information, see http://www.dcs.bbk.ac.uk/~sjmaybank.