Foveating infrared image sensors

Nova Sensors, under sponsorship of the Munitions Directorate of the Air Force Research Laboratory, has developed a readout integrated circuit (ROIC) technology for focal plane arrays (FPAs) that permits an intelligent use of the available image data; this is especially effective for dealing with the large volume of data produced by today's large format FPAs. The "Variable Acuity Superpixel Imaging" (VASI TM ) ROIC architecture allows for coverage of the entire field of view at high frame rates by permitting larger "superpixels" to be dynamically formed on the FPA in regions of relative unimportance, thus reducing the total number of pixel values required to be multiplexed off the FPA. In addition, multiple high-resolution "foveal" regions may be "flown" around the imager's field of view at a frame rate such that high-value targets may be sampled at the highest possible spatial resolution that the imager can produce. Nova Sensors has built numerous camera systems using 320 x 256 and 1K x 1K pixel versions of visible and infrared VASI TM FPAs. This paper reviews the technology and discusses numerous applications for this new class of imaging sensors.