Abstract: The visual enhancement problem of underwater robots is studied, and an image enhancement algorithm based on the improved dark channel prior (IDCP) algorithm is proposed to preprocess monocular vision images. Firstly, a degradation model of underwater image color slants and atomization phenomenon is developed. Then, the image of depth information is obtained through calculating the parallax between the brightness channel and the darkness channel to estimate the background color of the water accurately, and the corresponding transmission diagram is computed meanwhile. On this basis, the adaptive scaling factor selection strategy is adopted to postprocess the transmission diagram for the higher contrast image restoration effect. In addition, the color correction method is taken to remove residual color slants and enhance the overall brightness of the image. The experiment results in multiple underwater scenes show that the IDCP method can remove color slants and achieve visual enhancement with better resolution and brightness than the conventional ones.