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Proceedings Paper

Motion estimation with diffusion
Author(s): Joan V. Condell; Bryan W. Scotney; Philip J. Morrow
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Paper Abstract

This paper develops techniques for the implementation of motion estimation. Gradient-based approaches compute the spatio-temporal derivatives, differentiating the image with respect to time and thus computing the optical flow field. Horn and Schunck's method in particular is considered a benchmarking algorithm of gradient-based differential methods, useful and powerful, yet simple and fast. They formulated an optical flow constraint equation from which to compute optical flow which cannot fully determine the flow but can give the component of the flow in the direction of the intensity gradient. An additional constraint must be imposed, introducing a supplementary assumption to ensure a smooth variation in the flow across the image. The brightness derivatives involved in the equation system were estimated by Horn and Schunck using first differences averaging. Gradient-based methods for optical flow computation can suffer from unreliability of the image flow constraint equation in areas of an image where local brightness function is non-linear or where there are rapid spatial or temporal changes in the intensity function. Little and Verri suggested regularization to help the numerical stability of the solution. Usually this takes the form of smoothing of the function or surface by convolving before the derivative is taken. The method proposed is a finite element method, based on a triangular mesh, in which diffusion is added into the system of equations to perform a type of smoothing while also retrieving the velocity. Quantitative and qualitative results are presented for real and synthetic images.

Paper Details

Date Published: 19 March 2003
PDF: 12 pages
Proc. SPIE 4877, Opto-Ireland 2002: Optical Metrology, Imaging, and Machine Vision, (19 March 2003); doi: 10.1117/12.463754
Show Author Affiliations
Joan V. Condell, Univ. of Ulster at Coleraine (United Kingdom)
Bryan W. Scotney, Univ. of Ulster at Coleraine (United Kingdom)
Philip J. Morrow, Univ. of Ulster at Coleraine (United Kingdom)


Published in SPIE Proceedings Vol. 4877:
Opto-Ireland 2002: Optical Metrology, Imaging, and Machine Vision
Andrew Shearer; Fionn D. Murtagh; James Mahon; Paul F. Whelan, Editor(s)

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