In order to solve the problem of scattering artifacts in the computed tomography images, a modified Poisson distribution function is presented and used as the scatter model. A set of scatter basis images are obtained from scatter estimations with different parameter values in the model. Then the corrected image is obtained by adding the basis images to the original image. The coefficients for the linear combination are determined by minimizing the total variation of the combined images. The method requires low computational effort and allows flexible application to different scanned objects. Experiment results indicate that cupping and dark bands artifacts due to scattering are effectively depressed by the proposed method, and the image contrast is enhanced.%为了解决CT图像中散射伪影问题,提出并使用修正的泊松分布函数作为散射函数,然后利用卷积模型生成多个散射基图像,将基图像与原始重建图像的线性组合作为最终重建图像,最后,通过使重建图像的全变分函数最小求取线性组合系数最优解.该算法具有计算复杂度小、能够灵活应用于不同的成像对象的特点.实验结果表明,算法能够有效抑制散射导致的杯状和黑色带状伪影,提高图像对比度.
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