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

TL;DR

This paper introduces a novel interleaved row readout scheme for CMOS image sensors that significantly enhances dynamic range and signal-to-noise ratio, benefiting scientific imaging applications.

Contribution

The paper presents a new readout method that extends the full well capacity and improves dynamic range in CMOS sensors without increasing noise, enabling high HDR imaging.

Findings

Full well capacity increased 50 times

Dynamic range improved by 34 dB

Peak SNR increased from 43 dB to 60 dB

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 ke$^{-}$ to 984 ke$^{-}$ via an interlaced row-wise readout order, whilst 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 dB to 60 dB. This was achieved by summing user-selected rows which 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.