In the course of designing an integrated system for locating the focus of expansion (FOE) from a sequence of images taken while a camera is translating, a variety of direct motion vision algorithms based on image brightness gradients have been proposed (McQuirk, 1991 ; McQuirk, 1996). The location of the FOE is the intersection of the translation vector of the camera with the image plane, and hence gives the direction of camer a motion. This paper will describe two approaches that appeared promising for analog very large scale integrate d (VLSI) circuit implementation . In particular, two algorithms based on these approaches are compared with respect to bias, robustness to noise, and suitability for realization in analog VLSI . Based on these results, one algorithm was chosen for implementation and this paper will also briefly discuss the real-time analog CMOS/CCD VLS I architecture realized in the FOE chip.
Ignacio S. McQuirk, Berthold K. P. Horn, Hae-Seung