Effects of color CRT misconvergence, target size, and nontarget density on visual search performance

Rapid engineering developments in electronic imaging during the last decade have led to the widespread use of color CRT displays. misconvergence among the primary colors of a shadow-mask CRT is a principle human factors concern for applications of this technology. The major objectives of this research were: (1) to determine the effect of misconvergence on visual search performance (i.e., search time and error), (2) to examine the effects of misconvergence on subjective image quality estimates, and (3) to examine the interactions among target size, nontarget density, and misconvergence type and degree upon subjective and objective human performance indices.

Ten participants performed a visual "search-and-select" task on a color CRT computer workstation. Following each trial in this procedure, participants subjectively rated the image quality of the display screen using a 9-point scale.

Reducing target size increased selection errors and response times, while increasing nontarget density generally increased response times. Type and degree of shadow-mask CRT misconvergence had almost no effect on visual search performance, suggesting that low levels (1 to 2 arcmin) of misconvergence may be acceptable in effective color CRT applications. However, misconvergence adversely affected subjective image quality ratings, indicating that color CRT usage should be avoided where their use is not essential.