Phase‐based measurement of object velocity in image sequences using the Hough transform

Abstract

An alternative to traditional spatiotemporal gradient and feature-based approaches to measuring object velocity in images is in- troduced. Here, the velocity is computed by treating each object as a distinct intensity wave profile, with Fourier components, and by identify- ing the Fourier components that exhibit the magnitude and phase changes that are consistent with anticipated velocity wave motion. This detection is accomplished using an appropriate Hough transform. The two major advantages of this technique are that because the analysis takes place in the Fourier domain, the spatial organization and the visual appearance of the moving object are not significant and, second, the formulation presented in this paper lends itself to direct extension for more complex motion. Consequently, objects that are visually or spatially complex and that would be difficult to analyze using either of the tradi- tional spatiotemporal differentiation or feature-based approaches can be effectively treated. The proposed approach is demonstrated for scenes of varying complexity. © 1996 Society of Photo-Optical Instrumentation Engineers. Subject terms: velocity measurements; object motion; Fourier transforms; fre- quency phases; wave models; Hough transforms.