基于灰度加权的变电压CT重建算法

Gray Weighted CT Reconstruction Algorithm Based on Variable Voltage

常规固定电压CT重建,由于过曝光和欠曝光导致的不完全投影信息,成像质量差,为此提出变电压CT重建。通过变电压获得跟工件有效厚度相匹配的有效投影序列,在ART迭代图像的基础上,调整全变差使其最小化,来优化重建。在重建过程中,依据灰度加权,把低电压的重建图像作为初值,应用在相邻高电压有效投影重建中,得到相邻高电压的重建图像,依次类推直至最高电压,工件的全部结构信息重建完毕。实验表明,灰度加权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 projective data often appears overexposed or underexposed,and so the reconstructive results are poor.To solve this problem,variable voltage CT reconstruction has advanced.The effective projective sequences of a structural component are obtained through the variable voltages.Adjust and minimize the total variation to optimize the reconstructive results on the basis of iterative image using ART algorithm.In the process of reconstruction,the reconstructive image of the low voltage is used as an initial value of the effective projective reconstruction of the adjacent high voltage,and so on until to the highest voltage according to the gray weighted algorithm.That is to say the complete structural information is reconstructed.Experiment shows that the proposed algorithm can completely reflect the information of a complicated structural component,and the pixel values are more stable.