基于视觉定位的非确定轨迹CT系统

Dynamic orbit computed tomography with vision tracking

计算机断层成像(CT)系统需要精确和确定的扫描轨迹来获得高质量的图像。如果机械系统无法实现高精度的扫描轨迹,CT图像的质量将受到影响。该文提出了一种CT系统,通过视觉定位来实现非确定扫描轨迹下的CT成像。其中视觉定位系统通过对待测物体位移和转角的测量来获得实际扫描过程中射线与物体的精确几何关系。针对这种数据条件,提出了一种改进的滤波反投影(FBP)算法,实现非确定轨迹的CT图像重建。该方法将滤波反投影算法的适用范围从标准轨迹扩展到了通用轨迹。模拟数据计算和实验结果验证了该系统的可行性。此方法很大程度上为CT系统的设计提供了便利。

Traditional computed tomography（CT） requires an accurate and predetermined orbit to obtain high quality images.The quality of the reconstructed images is reduced when the mechanical system cannot ensure an accurate scan orbit.This paper describes a CT system with vision tracking which can deal with non-predetermined orbits.The vision tracking system obtains the actual geometry between the X-ray source and the object during the scanning process by tracking the rotation and displacement of the scanned object.A modified filtered backprojection（FBP） algorithm is used to reconstruct the images with the non-predetermined orbit.This algorithm extends the application of traditional FBP algorithms from a standard orbit CT to a general orbit CT.Simulations and experimental studies demonstrate the efficacy of this system that gives greater flexibility for CT system designs.