Closely-spaced-objects (CSO's) continues to be a critical issue for strategic infrared systems. Whenever a sensor's FOV encounters a high density of objects, tracking and discrimination performance can be critically affected by CSO's. The reason is that images (blur spots) on the sensor focal plane begin to merge as the distance between two objects is reduced. Some CSO's may be resolved by the signal processor, but more often the CSO is tagged without a resolution of the positions, amplitudes or number of objects from which it is comprised. We offer an approach, based on measurement of blurspot circumference which promises to advance the current performance limits for the CSO resolution function.