Abstract: Digital image processing based on real-time image enhancement techniques can effectively reduce the influence of fog and haze weather conditions on image quality. First, the critical factors that the color TV imaging system could be affected by atmospheric environment were analyzed. Then, two image enhancement methods, image enhancement method based on Retinex theory and nonlinear sub-block overlapping local balancing algorithm, were studied. Further, the performances of treatment effect and algorithm complexity of two types of algorithms were compared. The comparison results show that the non-line sub-block overlapping local equilibrium enhancement algorithm could achieve a balance between processing speed and effectiveness.