CAJ | 학술논문

鉴于非局部平均NL-Means（ Nonlocal Means）算法的高性能图像去噪表现，并考虑到重建速度这一重要因素，提出一种低剂量锥束CT稀疏角度3D图像迭代重建算法。首先，采用最小二乘方法进行图像重建以满足投影数据一致性，再对重建图像进行非负约束；然后，利用非局部平均算法对以上非负约束后的图像进行滤波处理，起到去噪保边缘的作用。以上各步骤均可以进行并行化处理，交替执行直至满足迭代终止条件。实验结果表明，该迭代重建算法获得了满意的3D图像质量，尤其适合并行化GPU加速，重建速度大幅度提升。
감우비국부평균NL-Means（ Nonlocal Means）산법적고성능도상거조표현，병고필도중건속도저일중요인소，제출일충저제량추속CT희소각도3D도상질대중건산법。수선，채용최소이승방법진행도상중건이만족투영수거일치성，재대중건도상진행비부약속；연후，이용비국부평균산법대이상비부약속후적도상진행려파처리，기도거조보변연적작용。이상각보취균가이진행병행화처리，교체집행직지만족질대종지조건。실험결과표명，해질대중건산법획득료만의적3D도상질량，우기괄합병행화GPU가속，중건속도대폭도제승。
In view of the denoising performance of high performance image in non-local means ( NL-Means) algorithm, and taking into account the important factor of reconstruction speed, we present an iterative reconstruction method for low-dose cone-beam CT 3D image with sparse-view.First, we utilise the least square method for image reconstruction to meet the consistency of projection data, and then apply nonnegativity constraints on the reconstructed images;Secondly, we use non-local means algorithm to make filtration processing on the images treated with nonnegativity constraints, which plays the role of denoising and edge preserving.The above steps can be parallelly processed and executed alternatively until the program meets the iteration termination condition.Experimental results show that the iterative reconstruction method achieves satisfied 3D image quality, it is especially suitable for paralleled GPU acceleration, and the reconstruction speed is greatly improved as well.