A CMOS sensor, when applied to IP surveillance cameras, is a device which converts light energy into electrical voltages which can be read by an IP camera and translated into images. In a similar manner to CCD sensors, CMOS sensors are made up of thousands or millions of light-reactive cells. Each reacts to a component of light; red, green or blue. The amount of light on each cell is translated into a voltage which is read by the camera and translated into data. This is then compressed and sent across the network to the viewing computer which arranges the data back in its original colour and position, providing a picture.
CMOS sensors are a newer innovation than the more common CCD sensors and thus the technology is improving all the time. CMOS sensors also require a lot less power than a comparable CCD sensor. CCD sensors tend to offer a higher quality image than a comparable CMOS sensor, although CMOS image quality is progressing and improving as time passes.