Max Planck Institute for Dynamics and Self-Organization -- Department for Nonlinear Dynamics and Network Dynamics Group
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BCCN AG-Seminar

Wednesday, 04.04.2007 16 c.t.

Border-ownership Determination by the Surround Modulation in Early Vision

by Prof. Dr. Ko Sakai
from University of Tsukuba, Japan

Contact person: J. Michael Herrmann

Location

Seminarraum Haus 2, 4. Stock (Bunsenstr.)

Abstract

Determination of border-ownership(BO), which indicates the side of figure with respect to a border, is a fundamental process for the assignment of figure/ground. We propose a computational model for the BO determination based on the surrounding contrast modulation reported in early visual areas, which comprises hundreds of model cells with their surrounding regions given randomly. Many model cells determined consistently BO for natural images and pseudo-random stimuli. The figure sides determined by the model show tendencies corresponding to Gestalt factors such as convexity, proximity and parallelism, indicating that the surrounding modulation observed in early vision appears to detect inherently the Gestalt factors for figure/ground grouping. We showed psychophysically that the reaction time of subjects for BO determination is proportional to the difficulty of the stimulus for the model. These results support a crucial role of the surrounding modulation in BO determination.

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