Night Vision Devices and Characteristics

Abstract : Night vision goggles (NVGs) are widely used to enhance visual capability during night operations. NVGs are basically composed of an objective lens which focuses an image onto the photo-cathode of an image intensifier tube which in turn produces an amplified image that is viewed through an eyepiece lens. There are several versions of NVGs in use and in development. These include the AN/PVS-5,AN/AVS-6, PVS-7, Cat's Eyes, Nite-Op, Eagle Eyes, Merlin, and others. The first section of this paper provides a brief description and characterization of each of these NVGs. There are several parameters that are used to characterize the image quality and capability of the NVGs. These parameters include field-of-view (FOV), resolution, spectral sensitivity, brightness gain, distortion, magnification, optical axes alignment, image rotation, overlap, beamsplitter ratio, exit pupil diameter, eye relief, and others. Each of these is discussed in the second section of this paper.