A fast algorithm for foggy image contrast enhancement

Thinking to the degradation of fog from images and the real-time processing requirements of visual navigation system for vehicle, a fast dynamic histogram equalization (FDHE) algorithm was presented. In the previous contrast enhancement algorithm, failed to take into account the speed and quality. Base on dynamic histogram equalization (DHE) algorithm which gained a better overall contrast enhancement with controlled dynamic range of gray levels, the FDHE expanded the image gray distribution, balanced the gray-scale distribution and processed speed to meet real-time requirement. It prevents the over-equalization of background region. The equalization of image is performed more evenly and the details of image are saved. The calculation of each pixel doesn´t complex and each pixel applied the dynamic histogram equalization. The algorithm can be widely used in the visual navigation system of intelligent vehicle, transportation, pilotless plane and so on to improve the reliability of system in foggy weather.