A research is carried out on the characteristics of CMOS (Complementary Metal-Oxide Semiconductor) image sensors. A
CMOS image sensor is used to probe the fluorescence intensity of atoms or absorbed photons in order to measure the
shape and atomicity density of Rb (Rubidium) cold-atom-cloud. A series of RGB data of images is obtained and the
spectrum response curve of CMOS image sensor is deduced. After filtering out the noise of the pixel signals of CMOS
image sensor, the number of photons received by every pixel of the CMOS image sensor is obtained. Compared with
CCD camera, the CMOS image sensor has some advantages in measuring the properties of cold-atom-cloud,such as
quick response, large sensory area, low cost, and so on.