A grayscale image based approach to estimating coverage ratio of Risley prism System

Risley prism is widely used in laser beam steering system due to its robustness, convenience in use, wide field-of-view, low power consumption, etc. In this paper, we suggested a novel approach to estimating the coverage ratio, which is one of the most important features of laser scanning system, by converting scan path into a grayscale image. This image indicates not only distributions of the scanning points but also their path densities in scanning area. By introducing this method, we can visualize the path density demonstratively and evaluate the coverage ratio quantitatively by analyzing the grayscale image. With this method we considered the effects of various parameters such as the rotation speed ratio on the coverage ratio. Simulation results showed enhanced uniformity of the scan image and increased coverage ratio under certain rotation speed ratio between the two prisms, and the coverage ratio approached rapidly to 100% after a few of acquisition durations in this case.