Faulkner K, Moores B M
Phys Med Biol. 1984 Apr;29(4):329-39. doi: 10.1088/0031-9155/29/4/003.
A discrete representation of the reconstruction process is used in an analysis of noise in computed tomography (CT) images. This model is consistent with the method of data collection in actual machines. An expression is derived which predicts the variance on the measured linear attenuation coefficient of a single pixel in an image. The dependence of the variance on various CT scanner design parameters such as pixel size, slice width, scan time, number of detectors, etc., is then described. The variation of noise with sampling area is theoretically explained. These predictions are in good agreement with a set of experimental measurements made on a range of CT scanners. The equivalent sampling aperture of the CT process is determined and the effect of the reconstruction filter on the variance of the linear attenuation coefficient is also noted, in particular, the choice and its consequences for reconstructed images and noise behaviour. The theory has been extended to include contrast detail behaviour, and these predictions compare favourably with experimental measurements. The theory predicts that image smoothing will have little effect on the contrast-detail detectability behaviour of reconstructed images.
在计算机断层扫描（CT）图像噪声分析中采用了重建过程的离散表示法。该模型与实际机器中的数据采集方法一致。推导出了一个表达式，用于预测图像中单个像素测量的线性衰减系数的方差。然后描述了方差对各种CT扫描仪设计参数（如像素大小、切片宽度、扫描时间、探测器数量等）的依赖性。从理论上解释了噪声随采样面积的变化。这些预测与在一系列CT扫描仪上进行的一组实验测量结果非常吻合。确定了CT过程的等效采样孔径，并指出了重建滤波器对线性衰减系数方差的影响，特别是其选择及其对重建图像和噪声行为的影响。该理论已扩展到包括对比度细节行为，并且这些预测与实验测量结果相比具有优势。该理论预测图像平滑对重建图像的对比度细节可检测性几乎没有影响。
