本文選題：短掃描　切入點：濾波反投影　出處：《中北大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：錐形束CT具有射線利用率高、掃描時間短、縱向分辨率高等優(yōu)點,因此被廣泛應(yīng)用于實際。錐形束CT重建算法中濾波反投影算法由于數(shù)學(xué)形式簡單,易實現(xiàn),得到了廣泛應(yīng)用。但是受實際應(yīng)用條件的限制,隨著掃描半徑的減小,錐角增大,重建質(zhì)量會下降。基于這個問題,本文主要研究內(nèi)容如下:(1)首先研究了掃描半徑對扇形束FBP算法重建精度的影響,實驗結(jié)果表明,掃描半徑越大,重建圖像質(zhì)量越好;接著研究了加權(quán)函數(shù)對重建精度的影響,實驗結(jié)果表明常數(shù)0.5加權(quán)比一般加權(quán)誤差更大。同時將以上結(jié)論推廣到錐束FDK算法。(2)平行重排(PFDK)算法是FDK算法的一種推廣,針對FDK算法隨著錐角增大重建精度下降的問題,給出了一種三維加權(quán)PFDK圖像重建算法,并研究了重排過程中徑向插值間隔對重建圖像質(zhì)量的影響,分別采用三種不同插值總數(shù)(插值間隔分別是1單位,0.5單位,0.25單位)重排數(shù)據(jù)。實驗結(jié)果表明給出的三維加權(quán)PFDK算法可有效減少錐角對重建結(jié)果的影響,且當(dāng)采用2倍插值總數(shù)時重建結(jié)果較好。
[Abstract]:Conical beam CT has the advantages of high ray utilization, short scanning time and high longitudinal resolution, so it is widely used in practice. Because of its simple mathematical form, filtering backprojection algorithm is easy to realize in conical beam CT reconstruction. It has been widely used, but limited by the practical application conditions, with the decrease of scanning radius, the conical angle increases and the reconstruction quality decreases. The main contents of this paper are as follows: firstly, the influence of scanning radius on the reconstruction accuracy of sector beam FBP algorithm is studied. The experimental results show that the larger the scanning radius is, the better the reconstructed image quality is, and then the influence of weighting function on the reconstruction accuracy is studied. The experimental results show that the constant 0.5 weighted error is greater than the general weighting error. At the same time, the above conclusion is extended to the cone-beam FDK algorithm. The parallel rearrangement PFDK) algorithm is a generalization of the FDK algorithm. In view of the problem that the accuracy of the FDK algorithm decreases with the increase of the cone angle, In this paper, a 3D weighted PFDK image reconstruction algorithm is presented, and the effect of radial interpolation interval on image quality during rearrangement is studied. The data are rearranged by three different interpolation totals (interpolation interval is 1 unit / 0. 5 unit / 0. 25 unit). Experimental results show that the proposed 3D weighted PFDK algorithm can effectively reduce the effect of cone angle on the reconstruction results. And the reconstruction result is better when the total number of interpolation is 2 times.
【學(xué)位授予單位】：中北大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TP391.41

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