發(fā)布時(shí)間：2018-02-11 06:07

  本文關(guān)鍵詞： 像素驅(qū)動(dòng) 射線驅(qū)動(dòng) 距離驅(qū)動(dòng) ASD-POCS算法 不匹配算法　出處：《中北大學(xué)》2017年碩士論文　論文類(lèi)型：學(xué)位論文

【摘要】：在醫(yī)學(xué)CT中,過(guò)大的掃描劑量對(duì)被掃描病人是有害的。低劑量掃描的一種有效方法是僅僅掃描稀疏視角下的投影。然而,基于稀疏數(shù)據(jù)的解析法重建會(huì)產(chǎn)生嚴(yán)重的條狀偽影,影響診斷。2006年,CS理論被提出,基于此理論設(shè)計(jì)的優(yōu)化算法可以從稀疏投影重建出高精度圖像。TV算法是一種有效的CS算法,該算法已經(jīng)被從理論到實(shí)踐深入研究,取得了一系列進(jìn)展。TV算法本質(zhì)上是迭代法,其成像問(wèn)題被建模為一個(gè)線性方程組。線性方程組的系數(shù)矩陣就是系統(tǒng)矩陣,表示如何求取投影。系統(tǒng)矩陣的構(gòu)建方法就是投影方法。投影方法的選取對(duì)TV算法的性能有一定影響。鑒于該問(wèn)題尚未被深入研究,本文擬聚焦該問(wèn)題,以期在系統(tǒng)比較各種投影方法的基礎(chǔ)上,揭示投影方法的選取對(duì)TV重建的影響。本文主要做了如下研究:(1)設(shè)計(jì)并實(shí)現(xiàn)了4種系統(tǒng)矩陣建模方法:像素驅(qū)動(dòng),距離驅(qū)動(dòng),改進(jìn)的距離驅(qū)動(dòng)以及射線驅(qū)動(dòng)(2)比較了它們的建模速度、建模精度(3)比較了在ASD-POCS算法中,4種建模方法對(duì)收斂速度的影響。(4)比較了它們?cè)谟性肼暤那闆r下對(duì)噪聲的敏感程度。(5)將不匹配理論與ASD-POCS算法相結(jié)合,實(shí)驗(yàn)驗(yàn)證在ASD-POCS算法中不同的不匹配對(duì)的表現(xiàn)性能。研究表明:距離驅(qū)動(dòng)的建模速度最快;改進(jìn)的距離驅(qū)動(dòng)的建模精度最高;射線驅(qū)動(dòng)在ASD-POCS算法中的收斂速度最快;匹配的投影、反投影對(duì)總是可以達(dá)到收斂但一些不匹配的對(duì)可能會(huì)導(dǎo)致發(fā)散,特別是在處理含噪的投影數(shù)據(jù)的時(shí)候,不匹配對(duì)更易發(fā)散。在所有不匹配對(duì)中,DD-RD具有良好的收斂性能可以成為不匹配對(duì)的推薦組合。這些研究,系統(tǒng)揭示了投影算法的選取對(duì)基于TV算法的圖像重建的影響,對(duì)于實(shí)際的醫(yī)學(xué)圖像重建提供了模型選擇依據(jù)。
[Abstract]:In medical CT, too much scanning dose is harmful to the scanned patients. One effective method of low dose scanning is to scan only the projection in sparse view. However, reconstruction based on sparse data can produce serious strip artifacts. In 2006, the CS theory was proposed. The optimized algorithm based on this theory can reconstruct high precision image from sparse projection. The algorithm is an effective CS algorithm, which has been studied from theory to practice. A series of progress has been made. The TV algorithm is essentially an iterative method, and its imaging problem is modeled as a linear equation system. The coefficient matrix of the linear equation system is the system matrix. The method of constructing system matrix is projection method. The selection of projection method has certain influence on the performance of TV algorithm. Since this problem has not been deeply studied, this paper intends to focus on the problem. In order to reveal the influence of the selection of projection methods on TV reconstruction on the basis of comparing various projection methods, this paper mainly studies the design and implementation of four system matrix modeling methods: pixel driving, distance driving, and so on. The improved distance drive and the ray drive compare their modeling speeds, In this paper, we compare the influence of four modeling methods on convergence rate in ASD-POCS algorithm. We compare their sensitivity to noise in the presence of noise. We combine the mismatch theory with ASD-POCS algorithm. The experimental results show that the performance of different mismatch pairs in ASD-POCS algorithm is the fastest, the improved distance driven modeling accuracy is the highest, the convergence speed of ray drive in ASD-POCS algorithm is the fastest, the projection of matching is the fastest. Backprojection pairs can always converge, but some mismatch pairs can lead to divergence, especially when processing noisy projection data. Mismatch pair is more prone to divergence. In all mismatch pairs, DD-RD has good convergence performance and can be used as a recommended combination of mismatch pairs. These studies reveal the influence of the selection of projection algorithm on image reconstruction based on TV algorithm. The model selection is provided for the actual medical image reconstruction.
【學(xué)位授予單位】：中北大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類(lèi)號(hào)】：TP391.41

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 伍偉文;全超;劉豐林;;相對(duì)平行直線掃描CT濾波反投影圖像重建[J];光學(xué)學(xué)報(bào);2016年09期

2 李磊;王林元;蔡愛(ài)龍;韓玉;閆鑌;包尚聯(lián);;基于等值線擬合的X射線雙能CT快速投影分解算法[J];光學(xué)學(xué)報(bào);2016年08期

3 付雨菲;王弘;邱曉明;尹建軍;韓丹;;減輕后顱窩偽影的后處理方案優(yōu)化的探討[J];臨床放射學(xué)雜志;2016年03期

4 查志遠(yuǎn);劉輝;尚振宏;李潤(rùn)鑫;;基于l_(1/2)范數(shù)正則化的圖像重建方法[J];計(jì)算機(jī)工程與應(yīng)用;2016年18期

5 喬志偉;;斜變?yōu)V波器頻域加窗對(duì)圖像重建的影響[J];計(jì)量學(xué)報(bào);2014年04期

6 古宇飛;閆鑌;李磊;魏峰;韓玉;陳健;;基于全變分最小化和交替方向法的康普頓散射成像重建算法[J];物理學(xué)報(bào);2014年01期

7 喬志偉;;能消除CT圖像角部誤差的斜變?yōu)V波器長(zhǎng)度選擇方法[J];計(jì)算機(jī)工程與設(shè)計(jì);2012年04期

8 喬志偉;韓焱;魏學(xué)業(yè);;用快速哈達(dá)瑪變換加速濾波反投影算法的濾波過(guò)程[J];電子與信息學(xué)報(bào);2010年09期

9 喬志偉;韓焱;魏學(xué)業(yè);;一種濾波反投影算法的加速方式[J];系統(tǒng)工程與電子技術(shù);2010年02期

10 練秋生;郝鵬鵬;;基于壓縮傳感和代數(shù)重建法的CT圖像重建[J];光學(xué)技術(shù);2009年03期

，

本文編號(hào)：1502373