The Japanese Journal of Psychology 1979, Vol. 50, No. 5, DISAPPEARANCE AND REVERSAL OF DEPTH IN STEREOPSIS KAZUO BINGUSHI Waseda University Fo

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1 The Japanese Journal of Psychology 1979, Vol. 50, No. 5, DISAPPEARANCE AND REVERSAL OF DEPTH IN STEREOPSIS KAZUO BINGUSHI Waseda University Four experiments were conducted to examine the transition of depth selection by mutual inhibition among disparities. (a) With random-dot stereograms, the time required for stereoscopic depth disappearance under fixation was found to be an in verse function of the magnitude of disparity. (b) Measurement of the cumulative time for perception of ambiguous stereograms showed that the depth was perceived longer with relatively smaller disparity. (c) The perception of stereoscopic depth under fixation was more stable in random-dot target than in ambiguous target. (d) Stereoscopic depth reversal occurred more frequently under fixation than in free observation. These results suggest that the whole range of disparities might be detected simultaneously and that the inhibition mechanism might have some important role in stereopsis.

2 FIG. 1. Median reaction time for disappear ance of depth under rigid fixation.

FIG. 3. Cumulative perception time for the depth of central target perceived in front of the surround (lower), and the number of depth rever sals (upper).

4 FIG. 3. Cumulative perception time for the depth of central target perceived in front of the surround (lower), and the number of depth rever sals (upper). The abscissae are the same in both figures and represent unit of repetition (1, 2, 3, 4) and the amount of disparity (1/4, 1/2, 3/4, 1). FIG. 2. Sample of ambiguous stereogram used in Exp. U.

6 TABLE 1 Reaction time for the disappearance of depth with random-dot target and for the reversal of depth with ambiguous target

7 TABLE 2 Number of times of depth reversals under free observation and under rigid fixation

8 Barlow, H. B., Blakemore, C., & Pettigrew, J. D The neural mechanism of binocular depth discrim ination. Journal of Physiology, 193, Fineman, M. B Facilitation of stereoscopic depth perception by a relative-size cue in ambig uous disparity stereograms. Journal of Experi mental Psychology, 99, Foley, J. M Binocular depth mixture. Vision Research, 16, Goryo, K., & Kikuchi, T Disparity and train ing in stereopsis. Japanese Psychological Research, 13, Gulick, W. L., Lawson, R. B Human stere opsis. A psychophysical analysis. New York: Oxford University Press. Hubel, D. H., & Wiesel, T. N Stereoscopic vision in macaque monkey. Nature, 225, Julesz, B Binocular depth perception of computer-generated patterns. Bell System Tech nical Journal, 39, Julesz, B Texture and visual perception. Scientific American, 212, Julesz, B Foundations of cyclopean percep tion. Chicago: University of Chicago Press. Julesz, B Global stereopsis: Cooperative phenomena in stereoscopic depth perception. In R. Held, H. W. Leibowitz, & H. L. Teuber, (Eds.), Handbook of sensory physiology, Vol. 8 Percep tion. Berlin, Heidelberg, New York: Springer Verlag Pp Julesz, B., & Miller, J. E Independent spatial frequency-tuned channels in binocular fusion and rivalry. Perception, 4, Julesz, B., Breitmeyer, B., & Kropfl, W, 1976 Bi nocular-disparity-dependent upper-lower hemifield anisotropy and left-right isotropy as revealed by dynamic random-dot stereograms. Perception, 5, Kaufman, L On the nature of binocular disparity. American Journal of Psychology, 77, Kaufman, L., & Pitblado, C Further obser vations on the nature of effective binocular dis parities. American Journal of Psychology, 78, Kaufman, L., Bacon, J., & Barroso, F Stere opsis without image segregation. Vision Research, 13, Nikara, T., Bishop, P. O., & Pettigrew, J. D Analysis of retinal correspondence by studying receptive fields of binocular single units in cat striate cortex. Experimental Brain Research, 6, Ogle, K. N The optical space sense. In H. Davson (Ed.), The eye. Vol. 4, New York: Academic Press. Pp

SUMMARY Four experiments were conducted in order to examine the transition of depth selection and to study how only a single depth plane could be perceived by mutual inhibition among disparities.

9 SUMMARY Four experiments were conducted in order to examine the transition of depth selection and to study how only a single depth plane could be perceived by mutual inhibition among disparities. Experiment T: With random-dot stereo grams of Julesz-type which differed in disparity, the time required for the stereoscopic depth disappearance was measured, under the condi tion that the subject fixated his eyes on to the mid area between two targets in the back ground. It was found that the reaction time was shorter when the magnitude of disparity was larger (see Fig. 1). Experiment U: With ambiguous stereo grams (see Fig. 2), one can see only one of the two depth planes at a time. The relative magnitude of the pair of crossed and uncrossed disparity was systematically changed so as to get various apparent depths, and the cumula tive perception time for each depth was meas ured for 90 sec. It was found that the depth of relatively smaller disparity was perceived longer regardless of the absolute magnitude of disparity and the direction of disparity (see Experiment V: The time required for depth disappearance with random-dot target as well as the one for reversal of depth with ambiguous target were measured on each trial. It was found that a shorter time was required for ambiguous target to be seen reversed than for the depth of random-dot target to disap pear. It suggests that the detection of disparity in suppressed depth might be strong enough to inhibit the detection of disparity in per ceived depth. Experiment W: With ambiguous stereo grams, the number of times of depth reversals was counted under fixation condition and fixation-free condition. It was found that stereoscopic depth reversal occurred more frequently under fixation than under fixation free condition. This result suggests that the detection of disparity in perceived depth de creases at a faster rate than in suppressed depth. These results suggest that the whole range of disparities might be detected simultaneously and that inhibition mechanism stated above might have some important role in stereopsis. Fig. 3).

24 Depth scaling of binocular stereopsis by observer s own movements

24 Depth scaling of binocular stereopsis by observer s own movements 1130313 2013 3 1 3D 3D 3D 2 2 i Abstract Depth scaling of binocular stereopsis by observer s own movements It will become more usual