Investigations of the Influence of the Degree of Coherence upon Images of Edge Objects*

Abstract

The theoretical irradiance is presented for the images of sharp-edged objects as a function of the coherence of the illumination of the object. These distributions are presented for optical systems possessing both square apertures and circular apertures. The irradiance for degraded edged objects is also determined for optical systems with square apertures. The influence of the degree of coherence upon contrast and edge gradient is considered in detail. Experimental results are given which show good agreement with the theoretical irradiance. In all cases the systems are assumed free from aberration and the quasimonochromatic assumption is employed.