Effects of pictorial noise interfering with visual detection.

In order to evaluate the potential gain of noise-suppression techniques, visual detection of sine-wave gratings in images with additive fine- and coarse-grain pictorial noise was investigated. An important part of the threshold elevations caused by pictorial noise can be explained in terms of masking. The threshold elevation can be reduced by about a factor of 7 through intelligent image processing. In addition to masking by similar noise components, the detection of low-spatial-frequency target detail can also be hindered by high-spatial-frequency noise components. Correspondingly, the detection of lower spatial frequencies can be improved moderately by blurring.