A Method to Achieve High Dynamic Range in a CMOS Image Sensor Using Interleaved Row Readout

Abstract

We present a readout scheme for CMOS image sensors that can be used to achieve arbitrarily high dynamic range (HDR) in principle. The linear full well capacity (LFWC) in high signal regions was extended 50 times from 20 to 984 ke − via an interlaced row-wise readout order, while the noise floor remained unchanged in low signal regions, resulting in a 34-dB increase in DR. The peak signal-to-noise ratio (PSNR) is increased in a continuous fashion from 43 to 60 dB. This was achieved by summing user-selected rows that were read out multiple times. Centroiding uncertainties were lowered when template-fitting a projected pattern, compared to the standard readout scheme. Example applications are aimed at scientific imaging due to the linearity and PSNR increase.