【作者】 刘博； 白相志； 蒋路帆； 周付根；

【Author】 Liu Bo, Bai Xiangzhi, Jiang Lufan, Zhou Fugen (Image Center, Beihang University, 100083)

【机构】 北京航空航天大学图像中心；

【摘要】 数字影像重建技术(DRR)在摆位验证、图像配准及治疗计划验证中起着至关重要的作用。针对目前常用的 DRR算法重建出的图像质量比较差,本文实现了一种实用的DRR算法。该算法采用光线追踪的思想,将光线所穿透的体数据所对应的电子衰减累加,并对累加后的数据进行增强处理,以得到对比度更强而又保留丰富细节的重建图像。文中讨论了光线遍历步长和采样点CT值插值方法对算法速度及重建图像质量的影响;分析了体数据CT值到电子衰减系数的转换关系;并提出了利用对数和指数转换的重建影像增强方法。实验结果说明该算法能获取较好图像质量,而且时间复杂度低,能够满足临床应用的要求。更多还原

【Abstract】 Digitally Reconstructed Radiographs( DRRs) play a important role in processing of position verification, image registration and treatment plan verification. Considering the poor image quality of DRRs commonly used, this paper implements a practical method based on ray tracing. As each ray is traced, an estimate of radiographic attenuation is obtained for the Hounsfield numbers associated with each CT voxel the ray passes through and all those values are added. Then, a post-processing enhancement method is utilized to make the image have large contrast and details. In this article, it has been discussed how the iteration step and interpolation method of Hounsfield numbers impact the processing time and image quality. More important. We study the relationship between the Hounsfield unit and radiographic attenuation and propose a image enhancement method using exponential and logarithmic transform. Through experiments, we find that this method could fulfill the practical need because of the pretty good image quality and the low time complexity.更多还原