Accession Number : ADA018566

Title :   An Experimental Evaluation of the Spot Wobble Method of Suppressing Raster Structure Visibility.

Descriptive Note : Technical rept. 1 Mar 73-1 Mar 74,


Personal Author(s) : Beamon,William S. ; Snyder,Harry L.

Report Date : NOV 1975

Pagination or Media Count : 47

Abstract : Television displays generate an image composed of a number of parallel raster lines. These lines, when visible, act as an interfering pattern and detract from operator performance in obtaining information from the video system. One way to reduce line visibility is to deflect the scanning spot vertically as it scans; this technique is commonly termed spot wobble. An experiment was conducted which evaluated changes in operator performance as indicated by the ranges at which targets were acquired and the number of correct responses to target presentation in a simulated air-to-ground search task. These performance parameters were evaluated at four spot wobble amplitudes and three viewing distances. The main findings were that spot wobble had no significant effect on the number of correct responses, but that large-amplitude spot wobble significantly increased the ranges at which targets were acquired. Additionally, several subjective indicators of preferred image quality were evaluated, and show that there is wide variance among subjects as to what image characteristics they prefer.

Descriptors :   *Display systems, *Human factors engineering, *Rasters, Images, Target acquisition, Television display systems, Modulation, Visual perception

Subject Categories : Electrical and Electronic Equipment
      Human Factors Engineering & Man Machine System

Distribution Statement : APPROVED FOR PUBLIC RELEASE