TARGET DETECTION USING BLACK-AND-WHITE TELEVISION. STUDY Ⅲ: TARGET DETECTION AS A FUNCTION OF DISPLAY DEGRADATION

摘要

Two previous studies have examined the probability of detecting an M-48 tankon a black-and-white closed-circuit television (TV) system, with apparently conflicting results. When only horizontal resolution was reduced to get resolutions of 300, 400, 600, and 800 lines, detection performance was essentially the same for the three highest resolutions, though significantly poorer for the 300-line resolution. Yet when resolu-tion was reduced in both horizontal and vertical dimensions, 800-line resolution gave better detection performance than 450 -line resolution did. Extraneous variables that could not be controlled -- such as uneven brightness and resolution on the TV monitors themselves -- made it difficult to interpret these results. Thus it was not clear whether the first result was an unlikely chance event or whether resolution's effect depends on the number of dimensions reduced. The present study replicated the first one to test its veriflability.nDisplays at all four levels of resolution were presented to 20 sub¬jects, who were asked to indicate in which one of nine areas the tank appeared on the TV screen.