Cite as:
Rosenzweig R, Schuchardt M, Wolf R, 2002, "Computation times for binocular depth perception: A psychophysical analysis of the 'delayed stereopsis illusion' (DSI)" Perception 31 ECVP Abstract Supplement

Computation times for binocular depth perception: A psychophysical analysis of the 'delayed stereopsis illusion' (DSI)

R Rosenzweig, M Schuchardt, R Wolf

Viewed pseudoscopically, an opaque square floating above a random-dot pattern appears as a rectangular cut-out. When the pattern moves upwards, an illusory gap is perceived at the upper edge of the square. In analogy with Julesz's 'no-man's-land' we called this DSI-gap 'trailing-edge no-man's-land'. Its width, marked by subjects under well-defined conditions, indicates the 3-D computation time needed to determine spatial depth of the pattern, which virtually appears 'from nowhere'. Early data suggested that in 3-D vision there are two different processing pathways for fast and slow movements [as Gegenfurtner et al (1996 Trends in Neurosciences 19 394 - 401) found in normal motion analysis]. Learning, and parameters like spatial frequency, disparity between the square and the moving pattern, and brightness within the range of photopic vision did not significantly influence the perceived width of the DSI-gap. In scotopic vision, however, it was increased in accordance with the Pulfrich effect.

[Supported by the Deutsche Forschungsgemeinschaft.]

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