Cohen G, McDaniel D L, Wagner L K
Med Phys. 1984 Jul-Aug;11(4):469-73. doi: 10.1118/1.595539.
Three sources of variability in a contrast-detail (CD) experiment have been quantitated: within-observer variance, between-observer variance, and sample variance. It is concluded that (1) it is more efficient to increase the numbers of replicated images and observers than to increase the number of readings; (2) sampling and between-observer variations are approximately equal; (3) one can expect approximately 10% standard errors in the measured value of threshold detail or threshold contrast in a CD experiment which employs four observers, four replicate image samples, and one reading per observer.
在一项对比度-细节（CD）实验中，已对三种变异性来源进行了量化：观察者内部方差、观察者之间方差和样本方差。得出以下结论：（1）增加重复图像和观察者的数量比增加读数数量更有效；（2）抽样变异和观察者之间的变异大致相等；（3）在一项使用四名观察者、四个重复图像样本且每位观察者进行一次读数的CD实验中，阈值细节或阈值对比度的测量值预计会有大约10%的标准误差。
