The Effect of Orientation Difference on Stereopsis as a Function of Line Length

The amount of depth seen in a multi-line stereogram composed of horizontal lines steadily decreases as the lines in one field of view are rotated about their midpoints. This effect of orientation difference on stereopsis is more acute the longer the lines in the stereogram. It is suggested that the critical factor underlying the depth reduction is not orientation difference per se, but rather the vertical disparity which an orientation difference introduces into the display between the tips of corresponding lines. This interpretation is supported by the fact that similar vertical disparities caused similar depth reductions regardless of the length of the lines in the stereogram.