
Absorption imaging using CMOS image sensors (CISs) enables non-invasive and non-destructive visualization and measurement of fluid concentration distributions. However, achieving high signal-to-noise ratio (SNR) under high illumination is challenging because large full well capacity (FWC) reduces conversion gain (CG) and increases input-referred noise. This work proposes a two-stage lateral overflow integration capacitor (LOFIC) CIS featuring dual pixel reset voltage (Dual VR) operation with an in-column programmable gain amplifier (PGA) and multi-sampling to suppress input-referred noise electron. The fabricated 140 × 140-pixel CIS achieved 130 dB dynamic range and 72.8 dB maximum SNR at 1000 fps. Imaging experiments demonstrated clear visualization of minute concentration variations, indicating suitability for high-speed absorption applications including in-chamber gas monitoring.