Perceptual evaluation of different nighttime imaging modalities

Human perceptual performance was tested with images of nighttime outdoor scenes. The scenes were registered both with a dual band (visual and near infrared) image intensified low-light CCD camera (DII) and with a thermal middle wavelength band (3-5 /spl mu/m) infrared (IR) camera. Fused imagery was produced through a pyramid image merging scheme, in combination with different colour mappings. For all image modalities, small patches of the scenes, displaying a range of different objects and materials, were briefly presented to human observers. The sensitivity of human observers was tested for different recognition tasks. The results show that DII imagery contributes most to global scene recognition, horizon detection, and the identification of water, roads and vehicles. IR imagery serves best for the detection and recognition of humans and buildings. Colour fused imagery yields the best overall scene recognition performance.