The Influence of Frame Rate and Resolution Reduction on Human Performance

Abstract

Unmanned Aerial Vehicles (UAVs) are used to conduct a variety of reconnaissance missions with human operators interpreting the transmitted imagery at ground stations. Current UAV data link designs require limited capacity which will result in a cost to the operator. Two common techniques to reduce video data rates exist, data compression and simple data reduction such as lowering of frame rate and resolution. The objective of this research was to determine the degree to which data volume can be reduced in terms of frame rate, spatial and grey-scale resolution, while retaining sufficient information to support human performance. Two studies were conducted to examine the influence of frame rate, resolution, and compression trade-offs. Experiment I utilized real mission imagery to assess operator performance in target detection, recognition, and designation. Experiment II used a simulation with dynamically manipulated UAV parameters to assess the influence of frame rate and resolution on target designation and tracking. Results indicate that frame rate has a greater influence than resolution on human performance in all four tasks. Overall, operators can perform tasks at rates reduced to 4 frames per second. Half resolution over the total display does not adversely affect performance except in recognition tasks. When resolution is calculated as a function of dynamically-controlled UAV parameters, 8 TV lines across the target appears to result in the best performance; however, these data are not as consistent as those in Experiment I.