Let us consider an optical imaging system formed by two point-objects incoherently illuminated and a thin positive lens delimited for circular pupil. The two point-objects image has two issues well-established. The first is when the two point-objects are close together and their images overlap considerably and the second one is when the distance between the two point-objects is widely large so that their images are separated. However, what happens when you can only see the image without you have the objects that formed this image? In this regard the resolution criteria are used. A resolution criterion gives the minimum distance in which the optical system is able to resolve the image of two objects when these are closely spaced. In this context, in the present master thesis we propose a new resolution criterion based on the Wigner distribution function properties (WDF) for two point-objects and its generalization for two quasi-point objects. Additionally, for a particular numerical example, this criterion is compared with the Rayleigh, Dawes and Sparrow criteria.