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在实际的三维锥束CT重建中,受扫描结构的限制,当连续X射线穿过物体时,像素对射线的采样间隔不能满足Nyqust采样定理,这样通道信号产生混叠,使得重建图像出现伪迹。本论文针对这一问题,在用splatting算法[1-2]计算代数重建算法权系数的基础上,分析了伪迹产生的原因并对对应的内插函数作了适当的变换,提出了适用于3-D锥束圆轨迹CT扫描系统的去伪处理方法。结果表明,经过去伪处理后,重建图像的分辨率明显提高。
In the actual 3D cone beam CT reconstruction, the scanning structure limits that when the continuous X-ray passes through the object, the pixel sampling interval can not satisfy the Nyquist sampling theorem, so the aliasing of the channel signal causes the artifacts of the reconstructed image . In this paper, on the basis of the calculation of the weight coefficients of algebraic reconstruction algorithm by using the splatting algorithm [1-2], this paper analyzes the causes of the artifacts and makes appropriate changes to the corresponding interpolation functions. 3-D cone beam trajectory CT scanning system to eliminate the pseudo-method. The results show that the resolution of the reconstructed image is obviously improved after de-dummy processing.