THE NOISE POWER SPECTRUM OF CT IMAGES
THE NOISE POWER SPECTRUM OF CT IMAGES
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DOI：
10.1088/0031-9155/32/5/003
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发表时间：
1987-05-01
影响因子：
3.5
通讯作者：
JUDY, PF
中科院分区：
文献类型：
--
作者：
KIJEWSKI, MF;JUDY, PF
推导了离散滤波反投影算法重建图像的噪声功率谱表达式。该公式明确地包括投影内的采样、角度采样和图像的离散表示中隐含的二维采样。插值的影响也被考虑。通过这种分析预测的噪声功率谱与使用连续理论预测的噪声功率谱在两个方面不同：它们是旋转不对称的，并且它们在零频率处不接近零。这两个属性都可以归因于由于像素采样而导致的二维混叠。通过测量模拟图像和来自商业X射线透射CT扫描仪的图像的噪声功率谱证实了预测。
An expression for the noise power spectrum of images reconstructed by the discrete filtered backprojection algorithm has been derived. The formulation explicitly includes sampling within the projections, angular sampling, and the two-dimensional sampling implicit in the discrete representation of the image. The effects of interpolation are also considered. Noise power spectra predicted by this analysis differ from those predicted using continuous theory in two respects: they are rotationally asymmetric, and they do not approach zero at zero frequency. Both of these properties can be atttributed to two-dimensional aliasing due to pixel sampling. The predictions were confirmed by measurement of noise power spectra of both simulated images and images from a commercial x-ray transmission CT scanner.