Resolution in model-based measurement

In measurement practice, the concept resolution is usually associated with the ability to distinguish two overlapping components of the same kind in observations. The original concept, Rayleigh´s well-known two-point resolution, stems from optics. It is based on the presumed limits of the human visual system to distinguish the images of two closely located point sources in observations of the sum of the images. Modern definitions of resolution, on the other hand, are based on parametric statistical models of the observations. They implicitly assume the use of parameter estimation methods and show that the ultimate limits to resolution are nonsystematic (statistical) and systematic (modeling) errors.