Influence of local scene colour on target detection tested by global rearrangement of natural scenes

Abstract

Local scene colour can influence the visual detectability of an object or target, but so can the familiarity, meaning, and global organisation of the scene. The aim of this study was to test whether the effects of local scene colour on target detectability are secondary to global effects. A target-detection task was undertaken by human observers with coloured images of natural scenes that were cut into quarters, randomly rearranged, and then reassembled. The target was a small, shaded, neutral grey sphere located randomly within the scene and matched in mean luminance to its local surround. It was found that observers' target-detection performance with the rearranged images was about as good as with the original images. The combination of local colour properties, namely, lightness and the red-green and yellow-blue components of chroma, accounted, respectively, for 55% and 50% of observers' detection performance with the original and rearranged images. Despite the disruption of global organisation, local scene colour continued to influence target detection.