Seungbae LEE, Satoshi SHIOIRI¹ and Hirohisa YAGUCHI¹

Graduate School of Science and Technology, Chiba University, 1-33 Yayoicho, Inage-ku, Chiba 263-8522, Japan
¹Department of Information and Image Sciences, Chiba University, 1-33 Yayoicho, Inage-ku, Chiba 263-8522, Japan

(Received October 24, 2002; Accepted December 9, 2002)

We measured disparity threshold for identifying the depth direction as a function of spatial frequency with various temporal frequencies and stimulus contrasts using drifting gratings. The results showed that disparity threshold depended little on temporal frequency with the exception of high temporal frequencies (≥10 Hz) independently of stimulus contrast. Contrary to temporal frequency, contrast substantially influenced spatial frequency characteristics. The disparity threshold was approximately constant with change in spatial frequency with slight increase at high spatial frequencies for contrasts higher than 0.2 when the threshold is expressed by phase difference between the left and right eye images (phase disparity). The phase disparity threshold had a negative peak at a spatial frequency between 1 and 5 c/deg (band-pass) for contrasts lower than 0.2. We discuss possible differences in the underlying mechanisms to determine disparity threshold below and above temporal frequency of 10 Hz.

Key words: temporal frequency, spatial frequency, contrast, disparity threshold, stereo acuity, stereopsis, phase disparity