Research On Diffraction Laser Spot Restoration Technology

In laser communication systems,a very small laser divergence angle is often required to avoid premature laser energy divergence,so the laser needs to be emitted through the optical system.After the laser passes through the optical system,the received spot image is blurred due to diffraction.Therefore,this paper proposes the research of diffraction laser spot restoration technology.In this paper,firstly the research background and significance of the spot test are introduced.And we study the current research of spot test technology and image restoration algorithm at home and abroad.Secondly,the effect of diffraction on the image is discussed,and the frequency spectrum shows that the effect is defocus blur.The image degradation restoration model of the diffraction spot is established and the quality evaluation standard of the restored image is explained.In addition,the principles of several commonly used image restoration algorithms are introduced in detail.This article proposes two improvements for the low noise resistance of defocus parameter estimation and the ringing phenomenon.Aiming at the problem that the defocus parameter estimation method is greatly affected by noise,it is proposed to use a bilateral filter to reduce the effect of noise while retaining edge details;for the ringing problem in the image restoration algorithm based on Richardson-Lucy,an improvement is proposed.The canny edge detection algorithm and morphological operation are used to obtain higher edge pixels,which are used as a weight array to constrain the restoration,which effectively suppresses the ringing phenomenon.Diffraction spot testing software was written with VC++,including four functional modules: video loading,spot restoration,data calculation and line graph drawing.The calculated spot center and spot radius reached the sub-pixel level,which meets the expected measurement accuracy requirements.As people have higher and higher requirements on detection accuracy,the impact of the diffraction limit of the optical system on the accuracy will become more and more significant.The research in this paper provides some reference value for the fields of laser communication and laser ranging.