11-15 講座預告:Nonconvex weighted variational metal artifacts removal via convergent primal-dual algorithms

發布時間:2023-11-14


題 目:Nonconvexweighted variational metal artifacts removal via convergentprimal-dual algorithms

内容簡介:Directreconstruction through filtered back projection engenders metalartifacts in polychromatic computed tomography images, attributed tohighly attenuating implants, which further poses great challenges forsubsequent image analysis. Inpainting the metal trace directly in theRadon domain for the extant variational method leads to strong edgediffusion and potential inherent artifacts. With normalization basedon pre-segmentation, the inpainted outcome can be notablyameliorated. However, its reconstructive fidelity is heavilycontingent on the precision of the pre-segmentation, and highlyaccurate segmentation of images with metal artifacts is non-trivialin actuality. In this paper, we propose a nonconvex weightedvariational approach for metal artifact reduction. Specifically, inlieu of employing a binary function with zeros in the metal trace, anadaptive weight function is designed in the Radon domain, with zerosin the overlapping regions of multiple disjoint metals as well asareas of highly attenuated projections, and the inverse square rootof the measured projection in other regions. A nonconvexregularization term is incorporated to further enhance edge contrast,alongside a box-constraint in the image domain. Efficient first-orderprimal-dual algorithms, proven to be globally convergent and of lowcomputational cost owing to the closed-form solution of allsubproblems, are devised to resolve such a constrained nonconvexmodel. Simulation experiments are conducted with comparisons to othervariational algorithms, validating the superiority of the presentedmethod. Especially in comparison to the reweighted JSR, our proposedalgorithm can curtail the total computational cost to at mostone-third, and for the case of inaccurate pre-segmentation, therecovery outcomes by the proposed algorithms are notably enhanced.

報告人:常慧賓

報告人簡介:天津師範大學數學科學學院,研究員,主要研究領域為計算光學、醫學圖像處理及高性能計算。2012年博士畢業于華東師範大學,2012-2013年在香港浸會大學從事博士後研究工作,2016-2019年訪問美國勞倫斯伯克利國家實驗室。

時 間:20231115日(周三)晚上2030開始

地 點:騰訊會議:870-549-992


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