According to image degeneration on foggy days, a penetrating fog imaging method using near infrared imaging and video image processing is proposed. According to the characteristics of low contrast image on foggy days and high comparability of histogram of contiguous field in video image, we have proposed an improved histogram equalization algorithm.This algorithm simplifies the system architecture as well as reduces the complexity of logical design. Moreover it also reduces the hardware resources of high speed memory. It has been simulated and verified on MATLAB and implemented on the video image processing platform based on FPGA. The experiment shows that the near infrared wave band has a better penetrating ability on fog. The improved algorithm enhances the image quality on foggy days while meet the real-time requirement for currently standard video image of 25 frame/s. With these two methods, we increase the visibility distance over 1.5 times on foggy days.