TARGET DETECTION USING BLACK-AND-WHITE TELEVISION STUDY III: TARGET DETECTION AS A FUNCTION OF DISPLAY DEGRADATION.
HUMAN ENGINEERING LABS ABERDEEN PROVING GROUND MD
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Two previous studies have examined the probability of detecting an M-48 tank on a black-and-white closedcircuit 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 resolution 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 resolutions effect depends on the number of dimensions reduced. The present study replicated the first one to test its verifiability. Displays at all four levels of resolution were presented to 20 subjects, who were asked to indicate in which one of nine areas the tank appeared on the TV screen. The results verified those of the first study the subjects detected targets about equally well with the 800-, 600-, and 400line resolutions, but their performance was significantly poorer with 300-line resolution. This finding suggests that, if resolutions are equal, reducing both horizontal and vertical dimensions will impair detection performance more than reducing just horizontal resolution i.e., reducing bandwidth. Author
- Optical Detection and Detectors
- Non-Radio Communications