Colour balancing of satellite imagery based on a colour reference library

Abstract

Generating mosaics of images obtained at different times is a challenging task because of the radiometric differences between the adjacent images introduced by the solar incident angle, atmosphere, and illumination condition. For most of the existing colour-balancing methods, the standard for determining the reference image is not unified, thus yielding different calibration results. Besides, traditional methods may suffer from colour error propagation and the two-body problems. A novel colour-balancing method for satellite imagery based on a colour reference library is proposed in this article, which aims to eliminate the effect of colour difference between different images for visually appealing and seamless image mosaicking. The proposed method contains two parts: the establishment of a colour reference library and the colour-balancing method based on it. Colour reference library is a database storing colour and other related information from the existing mosaic imagery. The colour information of the existing mosaic imagery is visually appealing and consistent with human visual perception. By automatically selecting appropriate colour reference information from the colour reference library according to the geographical scope and acquisition season information of the target images, the proposed approach provides effective solutions for choosing suitable reference image, colour error propagation, and the two-body problem in traditional colour-balancing methods. Experimental results demonstrate that the proposed approach performs well in the colour-balancing process.