Since the advent of microscopes, the analysis of medical images has become an important method in medical research. The emergence of new imaging technologies and equipment, as well as the development of computer technology, have led to an increasing role and impact of medical image processing technology on medical research and clinical practice. This article conducts research on weak edge extraction methods for complex medical images based on visual sensors. Through the research results, it can be found that the edge detection operator used in this paper as a weight matrix parameter enhances the connection strength between edge pixels. From the results, it can be seen that the image edge details are complete, continuous, and clear. This proves the feasibility of the method proposed in this paper. From the perspective of edge detection, people not only need perfect detection performance but also require accurate edge positioning. The visual sensor proposed in this article provides an ideal and practical solution for weak edge extraction in complex medical images.