The image sensor is a device that converts optical signals into electrical signals. According to different signal conversion methods, it is divided into CCD and CMOS. We mainly use CMOS image sensors.
Each image sensor has some differences such as resolution, sensitivity, pixel size, signal to noise ratio, size, etc.
Common sensor brands are sony, on semiconductor, Aptina, Omini Vision, Panasonic, Sam Sung, Smart Sens, HiMax, and so on.