Sensor Geometry and Sampling Methods for Space-Variant Image Processing

Ho, Cheyne Gaw, Young, Rupert C D and Chatwin, Chris R (2002) Sensor Geometry and Sampling Methods for Space-Variant Image Processing. Journal of Pattern Analysis and Applications, 5 (4). pp. 369-384. ISSN 1433-7541

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Abstract

Space-variant imaging sensors have many advantages over conventional raster imaging sensors. They provide a large field of view for a given pixel count while maintaining a high resolution at the centre of the field of view and, in addition, produce a mapping that is scale and rotation invariant. The effectiveness of the sensor depends greatly upon the geometry used and the sampling methods employed. In this paper, we define a sensor geometry and introduce an ideal weighted sampling method, where the pixels in the image lying at the intersection of sensor cells, are subdivided into smaller sub-pixels, and an interpolation method using a variable width interpolation mask, whose size varies exponentially with the size and shape of the cells in the sensor array. We compare the computational requirements of these methods, and show that they are scale and rotation invariant, when the image is scaled or rotated about its centre, giving the sensor a functionality similar to that provided by the retinal mapping present in the mammalian retina. These results illustrate the advantages that can be obtained in real-time tracking applications in computer vision, where computational and memory requirements need to be kept to a minimum.

Item Type: Article
Additional Information: The article reports a detailed consideration of logR-theta sampling geometries and their application to space-variant image processing. This formed the essential basis for research incorporating co-ordinate transformation as a pre-processing operation prior to the computation of wavelet bases for iris recognition technology. Coding techniques were developed for fast implementation of this algorithm on limited computational power devices forming the content of International Patent Application No PCT/GB2007/000591, one of two forming the intellectual property base of xVista Ltd, formed as a spin-out company to exploit the results of EPSRC-dti-Link project, Product Security, Grant No. GR/R02931/01 (contact: K.Obrams, karlis@xvista.co.uk, Tel:0113-262-9229)
Schools and Departments: School of Engineering and Informatics > Engineering and Design
Depositing User: Rupert Young
Date Deposited: 06 Feb 2012 20:45
Last Modified: 02 Apr 2012 13:42
URI: http://sro.sussex.ac.uk/id/eprint/27926
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