Under the weather conditions such as fog, the original scene acquired by the optical camera will have serious image degradation, for example the contrast and visibility of the image are reduced and the image is blurred.At present, in the field of image dehazing, the dark-channel priori algorithm has a good effect in solving the above problems.But in view of the computational complexity and real-time performance of the algorithm, it cannot be directly transplanted into the FPGA.Therefore, based on the dark-channel priori algorithm, this paper first uses a fast estimation method for atmospheric transmittance to reduce the calculation amount and at the same time weakens the Halo phenomenon of the traditional algorithm.Then, the auto level method is used to perform contrast stretching on the dehazed image for improving the dehazing effects.Experimental results show that the proposed algorithm not only meets the requirements of real-time dehazing, but also effectively improves the ability of image dehazing.