Abstract

Contrast energy thresholds were measured for noisy band-pass filtered Sloan letters K, H, O, and a plus pattern (+) at various center frequencies and bandwidths. Computer graphics were used to produce the stimuli on a computer monitor. In the center of the screen was a model stimulus without noise. On its right and left side was a window containing white static noise. One of the noise windows also contained the stimulus to be detected. The observer had to indicate, by pressing one of two keys on a computer keyboard, whether the stimulus was on the right or left side. A 2AFC method and unlimited viewing time was used.

© 1991 Optical Society of America