The effects of raster structure suppression on visual thresholds, target acquisition performance, and image quality

A television image is formed by a series of parallel luminous lines called a raster. The visual prominence of the raster structure interferes with the extraction of information from the image. The raster may be suppressed experimentally by a deflection process called spot wobble.

Experiments were conducted to determine the effects of raster structure suppression on visual sine wave modulation thresholds and dynamic target acquisition performance using normal and noise degraded imagery.

Results indicate raster structure suppression and improvements in Sine wave threshold sensitivity are correlated and that a suppressed raster significantly improves target acquisition performance for noise-free conditions.

Performance correlations with the modulation transfer function area (MTFA) image quality metric were not as good as were the correlations between observer task performance measures and areas under the threshold functions. A rationale for improving the efficacy of the MTFA image quality metric was postulated.