The Design Of Real-time Aerial Digital Image Color Reversion System

As the reconnaissance aircraft cruise time long and the scene's color temperature changes quickly, the images captured by airborne digital camera show color offset severely. In theory, the object's color we saw is not only related to its light reflection but also the light source. In order to adapt the small inside space of airborne optical platform, airborne digital cameras are almost single-CCD Bayer color camera. During the images downloading, Bayer color images data interleaving occurs and the image quality losses. To resolve the phenomenon of color offset and the data interleaving, we designed an automatic white balance and color image interpolation processing hardware system.At first, the paper introduced the basics of chromatics, tricolor principle, and analyzed the reason of the digital camera image color offset, leaded the concepts, algorithms and procedures of the Automatic White Balance; enumerated three common color interpolation algorithms: double linear interpolation method, based on edge interpolation method and chromatism stabilization interpolation method. And then, designed the FPGA-based hardware system for color reversion, completed the digital system design. At last, the pager stated the digital image effect managed by the color reversion system.This hardware system is highly integrated, lower power consumption, and it can adapt the complex on-board environment well. The Auto white balance circuit has self-convergence ability, and its convergence speed is fast. The color interpolation circuit achieves chromatism stabilization interpolation method, and the color image reversion effect is ideal. The hardware system can achieve real-time processing to the image sequence, image datas will not cause congestion, so the system can meet the needs of the practical application of engineering.