局部FBP图像重建算法的研究

FBP image reconstruction algorithms about region of interest

为了减少X射线对人体的伤害,局部(感兴趣区域,ROI,Region of Interest)图像重建算法成为人们研究的重点之一。首先,本文详细介绍了两种FBP算法的基本思想;其次,只用过ROI(或ROI加部分局部区域外)的投影数据进行相应区域图像的重建,会引起重建图像的边缘误差,文中结合边缘的投影数据延拓为相应沿径向未知投影数据的方法改进了重建图像的边缘误差,实验结果说明了此方法的有效性。最后,从算法的重建过程入手,只重建ROI那一部分,并将这一思想应用于FDK算法、Feldkamp-type-VOI算法、Katsevich算法,并进行了计算机模拟仿真实验,仿真实验结果验证了此方法的可行性。

In order to reduce the harm of X-ray on human body, local reconstruction for the region of interest is becoming one of the important studies in reconstruction. At first, reconstructing the local image by using the projection data through the region of interest generates the edge error in the reconstructed image in general.By making continuation along the radial direction, the method of data continuation was used in Feldkamp type reconstruction for the VOI. The result demonstrates the local reconstructed image is improved.Besides, the reconstruction for the region of interest can start from the process of reconstruction algorithms to get that part of region of interest, we describe the reconstructed methods of the helical cone beam FBP algorithm and a preliminary numerical study has performed for validating; Finally, we demonstrate the reconstruction results using computer simulation data. The results of the numerical experiment show that the method is very effective.