基于改进TV-ART的变电压CT重建算法

An Improved TV-ART CT Reconstructive Algorithm Based on Variable Voltage

常规固定电压的CT重建,因成像系统动态范围受限,投影数据易出现过曝光和欠曝光共存现象,信息缺失,成像质量差,为此提出变电压CT重建。针对变电压CT中的不完全投影数据重建问题,提出了基于改进TV-ART的变电压CT重建算法。该算法在改进TV-ART的基础上,依据灰度加权,把前一电压的重建图像作为初值应用到下一电压重建中,直至最高电压,实现有效投影信息的全部重建,完整地再现复杂结构件的内部结构信息。实验结果表明,跟直接利用传统TV-ART重建算法相比,本研究提出的算法不仅实现了变电压图像信息的完整重建,像素值也更加稳定。

In conventional CT reconstruction based on fixed voltage,the projection data often appears overexposed or underexposed. This is because the variations in the effective thickness of the component along the orientation of the X-ray penetration exceed the limit of the dynamic range of the X-ray imaging system. Complete structural information cannot be reconstructed. To solve this problem, variable voltage CT reconstruction has advanced. With the incomplete projection data of variable voltage CT reconstruction problem, the variable voltage CT reconstruction algorithm based on improved gray weight is proposed. In this new method, the previous voltagers reconstruction image is used as a initial value of the next voltagers reconstruction until to the highest voltage according to the gray weighted algorithm and improved TV-ART algorithm. That is to say the full projection information is reconstructed. Finally, experiment shows that, with the traditional TV-ART algorithm directly,the proposed algorithm can completely reflect the information of a complicated structural component, and the pixel values are more stable.