The employment of advanced digital image sensor readout integrated circuit (ROIC) technology will greatly enhance the functionality of the ACES-HY system. Specific improvements will be improved image quality resulting from the removal of existing electronic crosstalk artifacts and enhanced capability of the system to image small, fast moving objects. New digital ROICs will further extend system functionality by allowing electronic zoom, windowing/binning, adjustable frame exposure time, user controlled bit depth and extended intra-scene dynamic range by controlling gain on a pixel-by-pixel basis. The digital readout also enables integration of the imager with an on-chip image-processing engine to perform low-level image computations such as change detection, edge identification and wavelet transformation for JPEG2000 image compression and other video analytic computations. The proposed digital architecture, which employs a delta-sigma analog to digital converter at each pixel lets the user adaptively capture any desired level of scene information (resolution, field of view, bit-depth, dynamic range, and minimum light level) and it also provides reductions in size, weight and power (SWaP).
Benefit: Adaptive digital image sensor readout technologies with pixel-by-pixel gain control will greatly enhance intra-scene dynamic range and thereby reduce scene failures, which are especially problematic in infrared imaging. The new digital read out technology proposed for this application also allows a direct tradeoff of image bit depth for exposure time and it is capable of capturing fast transient events simultaneously with longer exposure scene capture through post-processing of the the imager output data. These capabilities will have a number of commercial applications, especially where high frame rate is needed such as in industrial machine vision applications and high-speed photography.
Keywords: Digital Read Out Integrated Circuits, Sigma-Delta Analog To Digital Converter, Infrared Detectors, High Speed Image Capture
