Stereopsis Based on Vernier Acuity Cues Alone

Abstract

Random-line stereograms were generated in which the only monocular cues were minute breaks occurring at random in thin vertical (or horizontal) line grids. The breaks were binocularly correlated. The stereograms yielded global stereopsis (of a square standing out in front of a surface) even with monocular breaks of as little as 16 seconds of arc, which is below the threshold for resolving two lines. This technique led to the clarification of relations between local and global stereopsis.