Received January 8, 010; Revised August 4, 010; Accepted September 30, 010 39, 1 010 598 604 808 0135 1 1 815 8540 4 9 1 The Effects of Stimulus Size and Retinal Position on Depth Perception from Binocular Disparity Masayuki SATO and Shoji SUNAGA Department of Information and Media Engineering, University of Kitakyushu, 1 1 Hibikino, Wakamatsu-ku, Kitakyushu, 808 0135 Department of Human Science, Kyushu University, 4 9 1 Shiobaru, Minami-ku, Fukuoka, 815 8540 The effects of stimulus size and retinal position on apparent depth from binocular disparity were measured using a random-dot stereogram with one dimensional DoG difference of Gaussian disparity modulation along either horizontal or vertical direction. The standard deviations of two Gaussians were 1 deg and 1.5 deg respectively, corresponding to 0.18 cpd peak spatial frequency. The stimulus subtended 10 deg to the direction with disparity modulation and the size perpendicular to that direction was varied from 0.5 deg to 0 deg in Experiment 1. The central area of, 6, 10, or 14 deg was blanked in the 0-deg test stimulus in Experiment. The results showed that stimulus size larger than 6 deg was necessary to detect disparity modulation along the horizontal direction, whereas to detect vertical modulation much smaller stimulus size was enough. Further analysis indicated that the cooperative interaction between the central and peripheral visual field in stereopsis was well explained by probability summation of outputs from insensitive local disparity detectors. Key words: binocular disparity, depth perception, stimulus size, retinal eccentricity, anisotropy 1. 1 7 Rogers Graham 1 Craik-O Brien- Cornsweet Bradshaw Rogers Hibbard 3 4 6 Gillam 7 9 E-mail: msato@env.kitakyu-u.ac.jp 598 34
1 1 1.. 1 Cambridge Research Systems VSG /5 CRT RDFH StereoGraphics Crystal- Eyes 3 57 cm CRT 104 768 1.3 arc min 0 /deg 3 3 10 Hz 60 1 1.3 cd/m 0.0 cd/m Fig. 1 Random dot stereogram illustrating an example of test stimulus used in A the vertical modulation condition and B the horizontal modulation condition in Exp. 1.. 0 40 4 3 1 3. 1 3. 1 Fig. 1 1 Fig. 1 A y x, y d DoG y y d A 3exp exp σ 15. σ A 3.3 arc sec 1790 arc sec d s 1 deg Fig. 1 B x 1 1.8 cd/m 6.1 cd/m 1.0 cd/m 0.036 cd/m 0.44 cd/m 0.071 cd/m 39 1 010 599 35
10 deg s 0.5 deg 0 deg 1 0.5 1 3 4 5 5 1 68 1 1 s 1 A 0.176 log 1.5 17 A 34 s 0.5 deg deg 6 deg 3 deg 6 deg 10 deg 14 deg 0 deg 5 4 3 3. Fig. SS A s 0.5 deg 6 deg deg 0 deg deg 6 deg Fig. Fig. Probability of correct response, opposite response, flat response, not fused response, and false match response for observer SS. 1 7 s 0.5 deg s deg s s 0 deg Fig. 0 deg 0 deg.4 deg 1 600 36
Fig. 3 Probability of correct response, opposite response, and flat response for four observers s 0.5 deg, vertical modulation condition. Fig. s Fig. 3 s 0.5 deg 4 SS YT MS 39 1 010 Fig. 4 Effects of stimulus size s on the probability of detection. p d p nd p nd p d p nd/ p nd/ p d 601 37
Fig. 4 4 Fig. 4 MS s deg SS YS s 8 9 1 4. 1 Fig. 5 Random dot stereogram illustrating an example of test stimulus used in the horizontal modulation condition of Exp.. 60 38 Fig. 6 Effects of gap size g on the probability of detection. 4. 1 Fig. 5 1 g deg 6 deg 10 deg 14 deg 4 4 3 4. Fig. 6 4 Fig. 4 g g 1 7 1 g 14 deg
Fig. 7 Stereo thresholds as a function of eccentricity. 1 deg 6 deg g 1 10 deg 10 deg 8 9 Fig. 6 50 Fig. 7 stereo threshold g Prince Rogers 8 DoG 0.18 cpd Prince Rogers Fig. 7 Prince Rogers Prince Rogers 39 1 010 Fig. 8 A Probability to detect horizontal depth modulation for the central stimulus Exp. 1. B That for the peripheral stimulus Exp.. C Probability of depth detection predicted by the probability summation model. N 4. Rawlings Shipley 9 1 deg 5. 1 s 0 deg 603 39
1 s 6 deg g 6 deg 1 s 0 deg s a deg g a deg s 0 deg 1 1 s 0 deg s 0 deg Fig. 8 Fig. 8 A 1 4 Fig. 8 B 4 Fig. 8 C 1 s 0 deg s g s g 6. 1 deg 0 deg 3 0 deg 1 B. J. Rogers and M. E. Graham: Anisotropies in the perception of three-dimensional surfaces, Science, 1 1983 1409 1411. M. F. Bradshaw and B. J. Rogers: Sensitivity to horizontal and vertical corrugations defined by binocular disparity, Vision Res., 39 1999 3049 3056. 3 P. B. Hibbard, M. F. Bradshaw, K. Langley and B. J. Rogers: The stereoscopic anisotropy: Individual differences and underlying mechanisms, J. Exp. Psychol. Hum. Percept. Perform., 8 00 469 476. 4 Cornsweet 33 004 667 677. 5 Cornsweet 34 005 606 613. 6 37 008 9 301. 7 B. Gillam, D. Chambers and T. Russo: Postfusional latency in stereoscopic slant perception and the primitives of stereopsis, J. Exp. Psychol. Hum. Percept. Perform., 14 1988 163 175. 8 S. J. D. Prince and B. J. Rogers: Sensitivity to disparity corrugations in peripheral vision, Vision Res., 38 1998 533 537. 9 S. C. Rawlings and T. Shipley: Stereoscopic acuity and horizontal angular distance from fixation, J. Opt. Soc. Am., 59 1969 991 993. 604 40