Continuous-time calibration of VLSI sensors for gain and offset variations
Parameter variations cause unavoidable nonuniformities in infrared focal plane arrays and other integrated sensors. A one-time calibration procedure is normally used to counteract the effect of these variations between components. Unfortunately, many of these variations fluctuate with time--either with operating point (such as data-dependent variations) or with external conditions (such as temperature). Calibrating these sensors one-time only at the `factory' is not suitable--much more frequent calibration is required. We have developed an adaptive algorithm that continually calibrates an array of sensors that contains gain and offset variations. This paper extends the work of Ullman and Schechtman who developed an algorithm for gain adjustment. The adaptive nonlinear dynamical system can be mapped to analog VLSI or a discretized version may be efficiently implemented in digital hardware.