Conspicuity of moving soldiers

The construction and validation of soldier combat models requires data on the conspicuity of camouflaged targets in the field, and human targets in particular. So far, this data is lacking. Also, it si currently unknown to what degree luminance contrast and motion contribute to target conspicuity. These data are needed to enable the validation and further development of human visual search performance modules in soldier combat models like SCOPE or IWARS. In this study we measured the conspicuity of a person wearing a Dutch army camouflage uniform, while he was either standing still, walking or running along a forest in the background, both for viewing with the naked eye (NE) and for viewing dynamic thermal scene recordings (IR). We varied the viewing distance (80m and 230 m), the camouflage pattern (woodland and desert), the type of background (pine-tree and deciduous forest), and season (summer and winter), The IR (thermal) conspicuity of the person was much larger than his NE (visual) conspicuity. In both cases the effects of movement were large and saturated as a function of retinal target speed. For NE, we find large effects of shading that can not explained by local luminance contrast variations. Also for NE, conspicuity was reduced in winter, probably as a result of an increase in scene clutter. The results suggest that conspicuity is not only a function of retinal target motion and global luminance contrast, but also depends on the amount of clutter in the scene. © 2011 SPIE.