How to "hear" visual disparities: real-time stereoscopic spatial depth analysis using temporal resonance

Bernd Porr, Alex Cozzi, Florentin Wörgötter
1998 Biological cybernetics  
In a stereoscopic system, both eyes or cameras have a slightly dierent view. As a consequence, small variations between the projected images exist ('disparities') which are spatially evaluated in order to retrieve depth information (Sanger 1988; Fleet et al. 1991) . A strong similarity exists between the analysis of visual disparities and the determination of the azimuth of a sound source (Wagner and Frost 1993) . The direction of the sound is thereby determined from the temporal delay between
more » ... he left and right ear signals (Konishi and Sullivan 1986) . Similarly, here we transpose the spatially de®ned problem of disparity analysis into the temporal domain and utilize two resonators implemented in the form of causal (electronic) ®lters to determine the disparity as local temporal phase dierences between the left and right ®lter responses. This approach permits real-time analysis and can be solved analytically for a step function contrast change, which is an important case in all real-world applications. The proposed theoretical framework for spatial depth retrieval directly utilizes a temporal algorithm borrowed from auditory signal analysis. Thus, the suggested similarity between the visual and the auditory system in the brain (Wagner and Frost 1993) ®nds its analogy here at the algorithmical level. We will compare the results from the temporal resonance algorithm with those obtained from several other techniques like crosscorrelation or spatial phase-based disparity estimation showing that the novel algorithm achieves performances similar to the'classical' approaches using much lower computational resources.
doi:10.1007/s004220050437 pmid:9691262 fatcat:5n2lreirk5g6plvfyyottfgcci