Measurement of Binocular Fusional Limit under Fixating and Free-observing Condition as Applied to a Design of Stereoscopic Image Parameters

Abstract

Binocular fusional limits are measured under two conditions for observing a small stereoscopic display with a short viewing distance. One is a free-observing condition in which a subject changes his gaze point between a far and a near target alternately and estimates fusional limit at each fixating point the other is a fixating condition in which a subject fixates on a center point and estimates the fusional limit for the whole screen. In the free-observing condition, fusional limit is in proportion to the viewing angle and has weak dependence on viewing distance. In some cases the fusional limit of the far point is smaller than the disparity when the lines of sight are parallel. In the fixating condition, the fusional limit is ± 40 [arc min] as a maximum, larger than Panum's fusional limit, and has weak dependence on viewing angle and viewing distance. A method to design stereoscopic image parameters to display all objects within a subject's fusional limit is examined using the measured fusional limits.