Performance Measures: Search Performance for Different Fields-of Regard (prestatiemeting se: zoekprstatie bij geinstrumenteerd zien)

摘要

This study investigates human visual search as a function of Field of Regard (FOR) size, Field of View (FOV) size, resolution, and target conspicuity. An experiment was performed in which participants searched for targets in realistic scenes. The FOR sizes were respectively 45 degrees, 90 degrees, and 135 degrees. The FOV sizes were 200 degrees, and 40 degrees. The resolution of the original scenes was degraded in two steps by subsampling and interpolation. Each participant searched a total of 560 scenes in 56 conditions (3 different FOR's, 3 different resolutions, 2 FOV's, 3 conspicuities). Time to detection was recorded. The results show that search performance is directly related to Field-of Regard size, while the size of the Field of View appears to have less impact on search times. Furthermore, target conspicuity also determines search performance, with high conspicuities giving short search times and low conspicuities giving long search times. The decrease in search times with increasing target conspicuity is sharper for large Field of Regards (135 degrees) than for small Field of regards (e.g. 45 degrees). We conclude that visual search performance is mainly determined by the size of the search area, and not so much by the size of the instantaneous Field of View. Furthermore, conspicuity is the most important factor in visual search.