This lecture covers techniques for noise suppression in optical image sensors, including fixed-pattern noise calibration and dark noise measurement. It also explains how to measure an optical image sensor, focusing on calibration, dark noise computation, and capturing the saturation level. The lecture delves into concepts such as dynamic range, well capacity, and the impact of Poisson noise on signal detection. Additionally, it explores the use of microlenses to improve sensor performance and discusses single-photon detectors, their metrology, and the challenges of afterpulsing and crosstalk.