Resolution metric for imaging systems

The resolution of an imaging system is an important metric for quantifying its optical performance. Commonly used metrics like the instantaneous field of view and the Rayleigh criterion have multiple drawbacks, e.g., they ignore aberrations and obscurations, assume spatially uniform detector response, and treat detector and optical resolutions separately. Here, we present a new metric, <i>Ω</i>_{<i>r</i><i>e</i><i>s</i>}, based on the point response function of an imaging system and demonstrate its advantages. We also relate this new metric to the matched filter signal-to-noise ratio and define a generalized two-dimensional sampling <i>Q</i> number.