Effects of Image Exposure Time and Size on Ship Identification on Television

Abstract

Human operators' ability to identify a ship on a television display was tested in a simulation experiment. The primary objective was to measure how well the operators could identify a single target from among several alternatives with different image exposure times and image sizes. A second objective was to evaluate two response strategies. In one the observer would view all ships in a set before making an identification response. In the other, he would designate the target when it was first seen. Image size had a far stronger effect on identification performance than exposure time. Identification probabilities were low at the smallest image size (7 TV lines) at all exposure times tested. With 10 or 13 lines across the image, the percentage of correct identifications increased between 2 and 4-sec exposure times, but the increase was slight between 4 and 6 sec. Giving the observer the opportunity to view all ships in the set before responding did not improve performance. The data suggests that exposure times should be at least 4 sec to maintain a high level of performance. Correct identifications can be made at the time the target is on the display (whether the target appears first or last in the set) without viewing all ships in a set. (Author)