Dissertation > Industrial Technology > Automation technology,computer technology > Computing technology,computer technology > Computer applications > Information processing (information processing) > Pattern Recognition and devices > Image recognition device

Research on the Image Restoration in Wave-front Coding Technology

Author ZhangXin
Tutor ZhangXin
School Graduate Schoo,Chinese Academy of Sciences
Course Optics
Keywords Wavefront Coding Depth of focus Image Restoration Wavelet Denoising
CLC TP391.41
Type PhD thesis
Year 2010
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Wavefront coding technique by adding a special phase plate in the common optical system wavefront is modulated such that its optical transfer function and purpose of the point spread function of defocus is not sensitive to achieve the expansion of the optical system, the depth of focus. Be obtained on the detector when the optical system with wavefront coding technology intermediate image is blurred, and requires a combination of valid digital image restoration techniques to obtain a final clear image. This paper focuses on image restoration algorithm applies to the wavefront coding system to carry out the research. Wavefront coding system in the form of the point spread function PSF is known, can be obtained through software simulation and experiment, but it with the conventional motion or defocusing caused degradation functions are different, and having a special form. In the the actual wavefront coding system imaging experiments based on the effect of the different recovery algorithms are discussed. Wavefront coding system for image restoration noise amplification, the signal-to-noise ratio and decreased problem, given a specific solution, and verified experimentally. The main contents include the following aspects: 1. Comprehensive description of the historical development and current status of the wavefront coding technology and its image restoration, while analysis of the characteristics of image restoration wavefront coding system, as well as the significance of the study. Introduces the basic theory of digital image restoration, including the basic concepts of image restoration problem model, several classic restoration algorithm and image quality evaluation methods, and the impact of noise and image restoration effect Denoising a brief description. The theoretical basis of the wavefront coding technology cubic phase plate in the form of the function and the stationary phase method based on fuzzy. Coding system, designed a three-phase plate and its imaging properties of optical design software and the development of the lens and the imaging experiments explore the wavefront coding imaging technology, imaging results, and the depth of focus of expansion capability. 4. The imaging wavefront coding system noise sources and types, the establishment of a noise model of the system and frequency SNR model for the noise present in the image restoration process of the encoding system wavefront larger, the SNR degradation problems, recovery algorithms, an improved the Wavelet Denoising LR recovery algorithm is introduced to solve the problem of noise amplification of the original LR algorithm. The experimental results show that this method is effective to suppress the noise, and to get a good recovery effect. 5 In order to further improve the resolution of the system of the wavefront coding, Superresolution study. Proposed to use a method based on the recovery of the optimal reconstruction theory by wavefront coding imaging system and recovery analog and found that the optimal reconstruction method to improve the resolution of the image of the wavefront coding system recovery.

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