Abstract
Purpose: :
There have been numerous reports on distortions in 2 dimensional visual perceptions. One of the notable is saccadic compression. But there are also reports that the fixation itself causes compression (Sheth BR & Shimojo S, 2001). These results are now tried to be explained on the modeling of 2-D spatial map but yet there hasn’t been a consideration for spatial map for depth. Here, we investigated depth perception during fixation and the looked for the similarities and dissimilarities.
Methods: :
4 subjects participated in the experiment. The depth stimuli were presented with anaglyphic method. The fixating depth stimuli were give in near (-3 pixel disparity), monitor and far (3 pixel disparity) plane. Probing stimuli were presented in two near (-4 pixel and -2 pixel disparity) and two far (2 pixel and 4 pixel disparity). Using 2-alternative forced choice method, after probing depth stimuli were presented, the subject asked to report the subsequent depth stimuli were near or farther. Psychometric functions and point of subject equality (PSE)’s were obtained.
Results: :
1. General PSE shift toward near was noted. 2. General compression toward monitor plane was noted all 4 probing depths. 3. Near and far fixating stimuli did not showed to be the center of compression rather seem to distract compression toward to the monitor plane. 4. Near and far fixating stimuli acted like repulsion center.
Conclusions: :
The result of compression gives the insight that the functional arrangement of depth spatial map might be similar to 2-D spatial map.
Keywords: depth • perception • discrimination