A mathematical index of uniformity (IOU) for sensitivity and resolution.

The authors define a mathematically precise index of uniformity (IOU) and show that the IOU is a convenient tool to quantitate uniformity of sensitivity and resolution response for any given area of interest on the detector face. They also show that the IOU is an appropriate factor for weighing the mean values of sensitivity and resolution for nonuniformity of response; these weighted sensitivity and resolution factors are used to derive a weighted figure of merit which takes into account, in a single parameter, the nonuniformities of response inherent in the determination of sensitivity and resolution.