Velocity tunings of binocular disparity channels for very large depth M Sato1, S Sunaga2 |
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1Dept of Information and Media Engineering, University of Kitakyushu, Japan |
| It is well-known that an excessive disparity causes diplopia and unclear depth impression. However, we recently found that target motion facilitates stereopsis for very large depth [Sato et al., 2007, ITE Technical Report, 31(18), 25-28, Sato and Sunaga, 2012, Perception, 41 ECVP Supplement, 71]. To examine the velocity tuning and temporal summation of the responsible mechanism, we measured contrast sensitivities for depth discrimination as functions of target velocity and duration using one-dimensional DoG targets (the space constants of positive and negative Gaussians were 68 and 102 arcmin, respectively, corresponding to 0.16 c/deg peak special frequency). Two targets (one above and the other below the fixation point) were presented for 0.05, 0.1, 0.2, 0.4, or 0.8 s in a raised cosine temporal window and 4.8 deg crossed and uncrossed disparities were given to one and other targets. These targets drifted horizontally in the opposite direction with velocity of 0, 7.5, 15, 30, 60, or 120 deg/s. The results show that the highest sensitivity was obtained at around 15-30 deg/s when the duration was long while velocity tunings were much broader when the duration was short. It appears that a dynamic mechanism tuned to that velocity range mediates stereopsis for large depth. |
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