Natural colour mapping for multiband nightvision imagery

We present a method to give (fused) multiband night-time imagery a natural day-time colour appearance. For input, the method requires a false colour RGB image that is produced by mapping three individual bands (or the first three principal components) of a multiband nightvision system to the respective channels of an RGB image. The false colour RGB nightvision image is transformed into a perceptually decorrelated colour space. In this colour space the first order statistics of a natural colour image (target scene) are transferred to the multiband nightvision image (source scene). To obtain a natural colour representation of the multiband night-time imagery, the compositions of the source and target scenes should resemble each other to some degree. The inverse transformation to RGB space yields a nightvision image with a day-time colour appearance. The luminance contrast of the resulting colour image can be enhanced by replacing its luminance component by a grayscale fused representation of the three input bands.