Fast reconstruction of computerized tomography images based on the cross-entropy method

作     者：Wang, Qi Wang, Huaxiang Yan, Yong 

作者机构：Tianjin Univ Sch Elect Engn & Automat Tianjin 300072 Peoples R China Univ Kent Sch Engn & Digital Arts Canterbury CT2 7NT Kent England 

出 版 物：《FLOW MEASUREMENT AND INSTRUMENTATION》 (流量测量与仪表设备)

年 卷 期：2011年第22卷第4期

页      面：295-302页

核心收录：

学科分类：080702[工学-热能工程] 08[工学] 0807[工学-动力工程及工程热物理] 0804[工学-仪器科学与技术] 0802[工学-机械工程] 

基　　金：National Natural Science Foundation of China [50937005  60820106002  60532020] 

主　　题：Computerized tomography (CT) Cross-entropy method Image reconstruction Multi-resolution decomposition Two-phase flow Wavelet transform 

摘      要：Computerized tomography (CT) has been applied to multi-phase flow measurement in recent years. Image reconstruction of CT often involves repeatedly solving large-dimensional matrix equations, which are computationally expensive, especially for the case of on-line flow regime identification. In this paper, a minimum cross-entropy (MCE) reconstruction based on wavelet multi-resolution processing, i.e., an MRMCE method, is proposed for fast reconstruction of CT images. Each row of the system s matrix is transformed by 1-D wavelet decomposition. A regularized MCE solution is obtained using the simultaneous multiplicative algebraic reconstruction technique (SMART) at a coarse resolution level, where important information of the reconstructed image is contained. Then the solution in the finest resolution is obtained by inverse fast wavelet transformation (IFWT). Both computer simulation and experimental work were carried out for oil-gas two-phase flow regimes. Results obtained indicate that the MRMCE method improves the resolution of the reconstructed images and dramatically reduces the computation time compared with the traditional linear back-projection (LBP), MCE and algebraic reconstruction technique (ART) methods. Furthermore, the new method can also be used to accurately estimate the local time-averaged void fraction of dynamic two-phase flow. It is suitable for on-line multi-phase flow measurement. (C) 2011 Elsevier Ltd. All rights reserved.