Abstract

Incoherent imaging and spatial filtering systems may employ illumination sources that are effectively discrete spatially. We show that such sources can be used while still preserving the linear-in-intensity imaging characteristics of the system. The source is modeled as a sampled continuous distribution, the Fourier optics methods are used to obtain a sampling condition that specifies the minimum allowable spacing between source points. This minimum spacing depends on the reciprocal of the smaller of the width of the object and width of the imaging system coherent point spread function. Relatively coarse sampling in the source plane is allowed in many cases of practical interest. We provide additional physical insight by examining the distributions (wave amplitude distributions and transmittance function) in the pupil plane of the system. Although linear-in-intensity imaging is maintained through observance of the source sampling condition, image-plane noise may increase because of the removal of redundancy.

© 1988 Optical Society of America