Blurred Image Restoration Based On Hartmann-Shack Wavefront Sensor

Because of the atmospheric turbulence, the wave-front passed through the atmosphere will produce different degree of distortion, so the images will be blurred. The quality of these images is not that ideal, the contrast and clarity are both lowered, which makes it necessary to restore the images. Traditionally, the adaptive optical system is adopted to restore the images. But the structure is of complexity, the system is consists of wave-front detection, wave-front reconstruction, wave-front correction, exact manipulation is needed and the cost is expensive. As a result, we come up with an idea that when we get the distorted wave-front from the Hartmann-Shack Wavefront Sensor, we adopt software method, which simplified the structure and get images of high quality.The paper introduces the background and significance of Hartmann-Shack Wavefront Sensor, summarizes the foremost application, and put forward an image restoration method based on Hartmann-Shack Wavefront Sensor. We emphasis on the wave-front reconstruction principle, describes four centroid methods and several image restoration methods. Image evaluation value by subjective and objective is introduced. Then we introduce the general model of Optical Transfer Function (OTF) and the way to calculate the OTF of diffraction limited incoherent image system. The result doesn’t include the case of wave-front distortion. Take the actual situation into consideration, wave-front distortion is unavoidable, so we deduce the method to calculate OTF with wave-front distortion and several general models with wave-front distortion.Then we summarize the reasons which caused the detection error of Hartmann-Shack Wavefront Sensor. Based on different wave-front detection error and the image restoration effect, we concluded the allowed maximum detection error of different P-V value of wave-front. In this paper, we build an experimental setup which uses the extended object as the target to prove the method we proposed. Subjective and objective evaluation value such as GMG and LS are adopted to analysis the effect of the restored images. The result shows that the method we proposed gets a good effect in image restoration.