Research On Medium And Long Distance High-resolution Imaging Technology And Experiment

With the advancement of science and technology,the demand for acquiring object information by optical imaging is increasing,and the requirements for image quality are getting higher and higher.Resolution is one of the criteria for measuring image quality.The higher the resolution,the more detail information is available.However,under the conditions of medium and long distance imaging in the natural environment,the effect of atmospheric turbulence will seriously affect the imaging quality of traditional optical systems,and it is difficult to achieve high resolution.In this paper,the high-resolution imaging technology based on telephoto lens with long focal length is studied under the condition of 50-200 m imaging distance in outdoor near-surface environment.In order to overcome the effect of atmospheric turbulence,combined with adaptive optics technology,the quality of the imaging system is improved by the combination of wavefront sensor hardware and image processing software.The main work and innovation are as follows:1.By analyzing the characteristics of near surface atmospheric turbulence,combined with adaptive optics technology,selecting a suitable telephoto telescope head and adaptive optics to complete the design of a medium and long distance high-resolution imaging optical path system of 50-200 meters.2.Aiming at the noise amplification phenomenon of turbulence degraded image restoration algorithm in iterative process,an improved twice bi-dimensional empirical mode decomposition denoising algorithm is proposed.By introducing the noise variance estimation,the algorithm can adaptively select the image-decomposed high-frequency noise components for filtering to achieve the noise constraint.Experiments show that the proposed algorithm can effectively improve the peak signal-to-noise ratio of noise images and maintain image details.3.The turbulence degraded image restoration method based on wavefront information in air is studied.The simulation experimental optical path system is designed and built.The experimental results verify the feasibility of the image restoration algorithm based on wavefront information to overcome the influence of turbulence.And the factors affecting the image restoration effect are analyzed.