According to one embodiment, the visual signature of a moving target may be measured by measuring, using a photometer, an optical property of a moving target while the target moves along a path from a start position to an end position in front of a background. The photometer may be repositioned to measure optical properties of the background at the start position. The photometer may measure the optical property of the background along the path between the start position and the end position. The visual signature of the moving target may be determined by comparing the measured optical property of the moving target along the path to the measured optical property of the background along the path.