Visual search

Visual search, with or without the aid of optical or electro-optical instruments, plays a significant role in various types of military and civilian operations (e.g., reconnaissance, surveillance, and search and rescue). Advance knowledge of human visual search and target acquisition performance is often required to prepare flight scenarios (e.g., for search and rescue operations) and to model mission performance (e.g., for military operations). In military scenarios, camouflage, concealment, and deception (CCD) measures are deployed to reduce the visual signature of targets, thereby maximizing the average time needed by an observer to find the target in the scene. In contrast, in civilian conditions, the visual signature or conspicuity of objects (traffic signs, road worker jackets, billboards) frequently needs to be boosted (e.g., by increasing the color, luminance, shape, or size contrast of the object with its surround) to ensure quick detection. Search time is usually adopted as the metric to quantify the effectiveness of CCD or conspicuity-enhancing measures. Effective CCD measures should result in an increase in search time, whereas effective conspicuity enhancement measures should result in a decrease of search time