Sensor Interpixel Correlation Analysis and Reduction: A Review

Abstract

Sensor interpixel correlation (IC), as caused by crosstalk, interpixel capacitance, the brighter‐fatter effect, blooming or smear, lowers the sensor MTF and increases color distortion in color filter array sensors. This is generally overlooked, and challenging to mitigate. Recent findings regarding scientific grade (CCD or hybrid CMOS) sensors, describe non-linearities causing pixel charge accumulation dependent IC. This is relevant even for lower grade sensors. High dynamic range imaging (HDRI) is especially susceptible to IC, because the sensor is deliberately operated partly in saturation. Existing HDRI algorithms exclude saturated pixels but generally overlook IC. This review article motivates the need for a generalization of the point spread function (PSF) into an irradiance-exposure dependent (IED) PSF, also considering supersaturation. The IED PSF is challenging to characterize and apply, partly due to its non-linearity. However, doing so can improve the MTF irrespective of image sensor technology, and for conventional as well as HDRI imaging.