Dynamic target identification on TV as a function of display size, viewing distance and target motion rate

Includes bibliographical references (pages 48-49)This report describes the result of a research study whose goal was the evaluation of the effects\ud of television display size, (2) display degradation, (3) observer viewing distance, and (4) target motion rate upon target identification performance. Appendices to the report describe (1) a\ud reconnaissance transparency projection system used to simulate the televisual air to surface\ud tactical target attacks used as test material in this study and (2) a rating procedure used to\ud compare target briefing photographs in terms of qualities important for target identification. The\ud target ratings are then used to predict target identification performance in the simulated target\ud attacks. Major conclusions are as follows:\ud 1. There was neither practical nor statistically significant difference in target identification performance among any of the monitor sizes investigated. (3-1/2-, 5-, and 8-inch diagonals).\ud 2. There was neither practical nor statistically significant difference in target identification performance between a degraded and an undegraded 8-inch monitor. Degradation consisted of reduction of grey-shade rendition form 9-8, and reduction of highlight brightness from 55 to 42 foot-lamberts.\ud 3. The visual angle subtended by displays is of major importance in predicting the target subtended angle at identification. As one moved closer to all of the displays used in the study, the diagonal target size at the eye of the observer required for target identification increased almost linearly with the ratio, TV height/viewing distance, which is the tangent of the angle subtended by the height of the display. 4. After the tangent function effect has been removed, 12 degree and 15 degree display viewing angle heights provide slightly better operational performance than do 6-degree, 9-degree, or 18-degree viewing angle heights. 5. Higher target motion rates require slightly larger target sizes for target identification to take place. 6.Factors which contribute to rapid target identification are large size, high contrast, low jaggedness, and low blur in that order. The same factors except for large size result in smaller target diagonal subtended angles at the eye of the observer when identification occurs. 7. By using the rating procedures outlined herein to evaluate reconnaissance photographs of targets, untrained observers can make accurate reliable cooperative judgments of target characteristics related to ease of target identification.\ud 8. Target ratings on contrast, blur, and jaggedness can be used to explain about half of the total variance described by the 32 targets "attacked??? during the simulation study.\ud 9. Improving target contrast offers greater improvement in target identification performance than does reducing target blur