Diffractive optical elements (DOEs) have been proposed for many applications. One of the principle limitations of these lenses is the abundant chromatic aberration that prohibits broadband use without design compensation. I propose a machine vision system that exploits this typically unwanted effect to provide information into a third dimension of current 2-D detection systems. This design implements a focal plane array with a diffractive focusing element. Output information can include the standard 2-D image, the distance to a component under test and if the object is in motion, the direction and velocity towards or away from the detector plane. This system can be designed to operate at visible or infrared (IR) wavelengths for a variety of inspection applications.
Denise M. Lyons, Denise M. Lyons,
"Range, direction, and velocity determination with a diffractive optic for robotic vision", Proc. SPIE 2269, Infrared Technology XX, (17 October 1994); doi: 10.1117/12.188662; https://doi.org/10.1117/12.188662