In the technique of robot-assisted invasive smgery, high quality image is a key factor of the visual navigation system. In this paper, the authors have made a study of the image processing in vi-sual system. Based on the analysis of plentiful denoising metbods,they proposed a new method(S-AM-W) which combines Adaptive Pepper noise and Gaussian noise). The simulation results show that it is simple, well real time, and has high Peak Signal-to-Noise Ratio (PSNR). It was found that the new method is effective and efficient in dealing with medical image of background noise.