Numerical Study on Iterative Image Restoration Algorithm

• Main Authors: Dah Chuan Hwang, 黃大川
• Other Authors: Suchung Hou
• Format: Others
• Language: zh-TW
• Published: 1994
• Online Access: http://ndltd.ncl.edu.tw/handle/23758600260768316208

碩士 === 國立成功大學 === 應用數學研究所 === 82 === Image restoration is to improve a photographic image under some criterions of goodness in reality. Restoration techniques are oriented toward applying the inverse process of degraded model in order to recover the original image from blur image. Degraded model can be formulated as blur integral equation for the purpose of the probelm. Now, we present a new choice of solving the blur integral equation by finite element method under the point spread function of out of focus blur. Thus we focus on a more modern algebraic approach for the observed large linear system with priori knowledge. On restoration method, we derive a new reblur operator H^2 more stable than previous H^TH from blur integral equation by finite element directly. We develop an approximation algorithm of estimating the condition of convergence of previous H^TH. Then two iterative algorithms CGM( conjugate gradient method ) and PCGM( preconditioned conjugate gradient method ) are applying to the large linear system. In experiment, we try to test our restoration method through several levels of additive noises. At last, we do error analysis on H^2 and H^TH in view of norms and then complete analysis of performance measure of approximation algorithm.