Evaluating Image Sensor Sensitivity by Measuring Camera Signal-to-Noise Ratio

摘要

Image sensor sensitivity is critical for machine vision applications where illumination is limited and large depth of field is required. In this paper a method is presented for evaluating image sensor sensitivity by measuring camera signal-to-noise ratio (SNR). The method is simple to implement and produces accurate results. The method measures SNR as a function of target illumination, and relates this to image sensor sensitivity by normalizing with respect to image sensor pixel size. The method can be used to compare cameras with different types and sizes of image sensors, and is particularly useful in comparing the sensitivities of different CMOS sensors, and for comparing CMOS and CCD sensors. We present a new measure of sensitivity: SNR per unit luminous flux-time. The new measure enables the direct comparison of sensor performance.