激光与光电子学进展, 2016, 53 (9): 093401, 网络出版: 2016-09-14
基于小波分析的分能段计算机断层扫描成像
Segmental Multi-Energy Computed Tomography Imaging Based on Wavelet Analysis
X射线光学 分能段投影 小波分析 低频分量 灰阶 X-ray optics segmental multi-energy projection wavelet analysis low frequency component gray-step
摘要
X射线多能计算机断层扫描(CT)方法通过多次圆轨迹扫描获取不同能量下的投影数据进行图像重建,扫描效率较低,受辐射剂量较大。分能段CT成像方法依据传统圆轨迹CT,对不同扫描角度采用不同能量,获取分能段投影。针对分能段投影的灰度阶跃问题,采用精确高频定位的小波分析方法,结合小波低频的灰阶高度修正小波系数,实现小波逆变换后投影的灰阶修正,通过重建实现分能段CT成像。仿真结果表明,与硬化伪影校正方式相比,该方法在增加能量信息的同时消除了灰阶引起的灰阶伪影,可有效提高重建图像对比度并改善硬化伪影现象。
Abstract
The X-ray multi-energy computed tomography (CT), which primarily reconstruct images by collecting projections obtained by repeated circular scans at different energy, shows low scan efficiency and large dose of radiation exposure. The segmental multi-energy CT is studied. The tube voltage in every arc of a traditional circular trajectory CT scan is different to obtain the segmental multi-energy projection. Based on the accurate location of high frequency in the wavelet analysis, the gray-step of segmental multi-energy projection is corrected by the gray-step height of low frequency, and the segmental multi-energy CT imaging is realized. The simulation results indicate that compared with the hardening artifact correction mode, the method based on wavelet analysis eliminates the gray-step artifact, extends the energy spectrum information, and improves the reconstructed image contrast and hardening artifacts effectively.
孙春霞, 潘晋孝, 陈平. 基于小波分析的分能段计算机断层扫描成像[J]. 激光与光电子学进展, 2016, 53(9): 093401. Sun Chunxia, Pan Jinxiao, Chen Ping. Segmental Multi-Energy Computed Tomography Imaging Based on Wavelet Analysis[J]. Laser & Optoelectronics Progress, 2016, 53(9): 093401.