Events
The Taub Faculty of Computer Science Events and Talks
Ohad Ben-Shahar (Computer Science, Ben Gurion University)
Tuesday, 22.03.2011, 11:30
The phenomenon of visual curve completion, where the
visual system completes the missing part (e.g., due to occlusion)
between two contour fragments, is a major problem in
perceptual organization research. Previous computational
approaches for the shape of the completed curve typically
follow formal descriptions of desired, image-based perceptual
properties (e.g, minimum total curvature, roundedness,
etc...). Unfortunately, however, it is difficult to determine
such desired properties psychophysically and indeed there
is no consensus in the literature for what they should be. Instead,
in this paper we suggest to exploit the fact that curve
completion occurs in early vision in order to formalize the
problem in a space that explicitly abstracts the primary visual
cortex, namely the unit tangent bundle R2 ×S1. We show that a basic
principle of “minimum energy consumption” in this space,
i.e., a minimum length completion, entails desired perceptual
properties for the completion in the image plane.
We present formal theoretical analysis and numerical solution
methods, we show results on natural images and their
advantage over existing popular approaches, and we discuss
how our theory explains recent findings from the perceptual
literature using basic principles only.