Abstract: Stereoscopic depth perception for position and for motion was observed andmeasured using a visual psychophysical experimental set designed and madeby ourselves. It seems that vergence movement takes an important part in thecorrect perception of stereoscopic depth.Under the condition of free vergence movement, the perceived depth forposition is consistent With the given binocular disparity up to the range of 3deg. The result. shows that human visual system can Perform algorithm of bi-nocular disparity. It is observed that at large disparity tbe correct perceptionof depth position could not, be reached without vergence movement. The ver-gence movement also plays an important role in stereoscopic perception for mo-tion in depth at large modulation amplitude of disparity. Besides, it is respon-sible for maintaining the perception of motion in depth.A latent period, about 0.15-0.18 sec., is observed by measuring the re-sponse time of stereoscopic depth. It is mainly due to vergence movement.

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