Scatterometer for measuring the 3-D distribution of transmitted energy from coatings in IR imaging systems

A novel IR transmission scatter measurement technique and design was invented that collects the transmitted energy scattered within defined annular aperture zones by coated optics such as BPFs. The measured annulus-resolved emergent scattered energy distribution corresponds to that present in the focal cone of imaging optics. Annulus Resolved Scatter (AnRS) is a tool available to the IR systems engineer who is concerned with minimizing image contrast reduction caused by scatter from coated optics located close to image sensor arrays. The prototype AnRS instrument demonstrates the proof-of-concept with moderate (2°) resolution at high SNR and is limited in spectral applicability only by detector and optics properties.