CCD vs CMOS

The image sensor is the camera component which captures light and begins the process of turning it into a digital image. There are two types of security camera sensors: CCD (charge coupled device) and CMOS (complementary metal oxide semiconductor). Which of the two you choose depends on your application.

With a CCD sensor, every individual pixel's charge is transferred through an output node, which is converted into an electrical signal. The signal is then buffered and sent as an analog signal. Because the pixels are devoted to light capture, the image quality is usually pretty high.

With a CMOS sensor, every individual pixel performs its own charge-to-voltage conversion, and the sensor performs amplification and noise-correction. The sensor also includes digitization circuits, which allow the component to output information in a digital format. Because of the complexity of this design, the area devoted to light capture is reduced. And because each pixel must perform its own conversion, uniformity (image quality) is lower.

Both technologies have their place in the marketplace. If your goal is to have good low-light-level surveillance, then a CCD camera is the best. If there is little to no light, CCD sensors used with IR illuminators produce an excellent picture. If indoor lighting is adequate, and megapixel quality is your goal, then CMOS technology may be your best bet.

Make sure you test your camera with the lighting that will actually be present in the field of view. Do not rely on manufacturer’s data sheets for the minimum useable picture. This figure is often subjective, and your customer may not find the results acceptable. CMOS cameras are more prevalent in the IP network world. These cameras are typically equipped with built-in Web Servers, which enable remote viewing of video from other locations, by using IP network protocol.

In conclusion, CCD sensors are the best for outdoor applications, low light scenarios or when a higher quality image is required. CMOS sensor cameras should mostly be considered for indoor applications, though with adequate lighting conditions, they may also work well outdoors.