Are there metrics that quantify whether items in an image are discriminable or identifiable?
I am not aware of formal definitions, but there does seem to be some common practice. Discriminability refers to the observers ability to detect objects in the image and determine that they are indeed different from one another. Identifiability would imply that the observers can also identify just what the objects are. Another term sometimes used in perception is detectability, which implies that the observer can tell that something is present, but not discriminate it from other objects, or identify it. Overall performance of an imaging system would have to be defined based on the application of interest and some metric the capability for the images to assist in that task.
