Size Discrimination Of Features On CT Images
Size Discrimination Of Features On CT Images
复制标题
CT 图像上特征的大小辨别
DOI：
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发表时间：
1986
期刊：
影响因子：
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通讯作者：
R. Swensson
中科院分区：
文献类型：
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作者：
P. Judy;R. Swensson
观察者评估CT图像上两个圆形特征大小不同的可能性，或者CT图像上存在环的可能性。环形特征是通过减去必须区分的两个磁盘的图像配置文件而产生的。由于物理互关器在两个任务中对图像像素值使用相同的形式计算，因此可以从环识别任务的信噪比值预测大小识别任务的信噪比（SNR）。这两个任务中的15组图像研究了三个级别的特征对比，以区分磁盘直径的相对差异，以在可测量的范围内调整观察者的表现。从观察者的ROC曲线估计的性能准确度指标，通过假设它们与任务信噪比的计算值成正比，可以很好地预测。尺寸识别和环检测任务的拟合比例常数相似，分别为0.470和0.556。人类也是如此。在大小识别和环检测任务中，观察者对图像信息的处理与物理交叉相关器相似，但效率较低。
Observers rated the likelihood that two circular features on a CT image differed in size, or the likelihood that a ring was present on a CT image. The ring features were produced by subtracting the image profiles of the two disks that had to be distinguished. Since a physical cross-correlator used the same formal calculations on the image pixel values in both tasks, the signal-to-noise ratio (SNR) for the size discrimination task could be predicted from the values of SNR in the ring discrimination task. The 15 sets of images in both tasks studied three levels of feature contrast for discrimination with the relative difference in the disks' diameters adjusted to vary observers' performance over a measureable range. Indices of performance accuracy, as estimated from observers' ROC curves, were well predicted by assuming that they were proportional to the calculated values of Task SNR. The fitted constants of proportionality were similiar in both the size-discrimination (0.470) and ring-detection (0.556) tasks. Thus the human. observer's processing of image information in both the size-discrimination and ring-detection tasks was similar to, but less efficient than, that of the physical cross-correlator.