The Technology And Applications Of Adaptive Optical Image Restoration

Adaptive optics is a leading technology which is based on the optical wave-front aberration asthe research object, which can be real-time, fast and accurate to dynamically measure, control andcorrect wave-front aberration. The development of the technology makes it possible to correct humaneye aberration and image vivo human eye retina with high resolution, which is benefit for earlydiagnosis of various retina related diseases, better treatment of diseases. However, the residualwave-front aberration, the capability limits of deformable mirror spatial correction and the influenceof frequency domain control bandwidth make that the human wave-front aberration can’t be correctedcompletely, the residual wave-front aberration can’t be missed and the high frequency information ofthe object is restrained and decayed, which decrease the contrast and resolution of images and affectus to observe the adaptive optics image. Therefore, the adaptive optics image must be processed basedon digital image restoration techniques, which can eliminate residual wave-front aberration andacquire high-definition objective image. This paper which views the adaptive optics images as theresearch object, and studies on some theory and algorithm about adaptive optics image restoration.The main work include as follows:1The detailed introduction of the adaptive optics technologies. This part includes the beginningand development of the adaptive optics technology, the limitations of the adaptive optics technologyand the adaptive optics image restoration development at past and present.2The model of Zernike based on partial ridge estimation for wave-front aberrationreconstruction In view of the wave-front reconstruction model with Zernike modes, the least squaresestimation and partial ridge estimation based wave-front reconstruction algorithms were proposed inorder to meet the real-time requirement in adaptive optics system and high precision in adaptive opticsimage restoration respectively.3The reason of adaptive optics image degradation, the mathematical model of adaptive opticsimage degradation and restoration are reconstructed as well as analysis the restoration of the opticaltransfer function in adaptive optics. Besides, the algorithm of subjective and objective qualityevaluation is proposed at the view of image restoration.4Adaptive optics image restoration based on wave-front aberration detection. Because thetraditional algorithm of iterative blind deconvolution can’t make use of the wave-front aberration,which makes the result instability. Therefore an algorithm based on wave-front aberration detection.were proposed, which modified the iterative blind deconvolution by means of somerestriction and some information of residual aberration. The experiment showed that the algorithm canimprove the image quality.5Image restoration based on dual tree complex transform (DT-CWT). The algorithm ofmulti-direction was brought into the adaptive optics image restoration. By means of anglicizing thecharacter of DT-CWT, the combination of dual tree complex transform and the image processingalgorithm of semi-blind deconvolution was proposed. The adaptive optics system is decomposed withDT-CWT into two parts. The low frequency image is processed by the algorithm of semi-blinddeconvolution with some constraints and the high frequency image is processed by denoising. Thefinally result showed that this algorithm is used for the image restoration.On the basis of the above research result, the system of adaptive optics image restoration hadbeen reconstructed building on the wave-front aberration detection. The initial point spread functionwas built by making use of the residual wave-front aberration. Therefore, semi-blind deconvolutionrestoration based on wave-front diction or semi-blind deconvolution restoration based on dual treecomplex transform was used for adaptive optics images which were affected by different noise. Theresults show that the system can improve the adaptive optics image quality.