Differences In CCD And CMOS Video Image Sensors


One can only assume that the popularity of CMOS is mainly because they are more prevalent in security IP-cameras. The difference between CMOS and CCD chips is the CMOS outputs its information in digital format and requires less power to operate.

These features will play heavily in the design of IP-cameras. As for the imaging sensor differences, we will elaborate a little more.

Every individual pixel’s charge, in a CCD image sensor, is transferred through an output which is then converted into an electrical signal. This signal is then sent as an analog signal.

As each pixel in a CCD is completely devoted to light capture, the image quality is usually pretty high.

On the other hand, With CMOS sensors, each individual pixel performs its own charge-to-voltage conversion. Also, the sensor performs amplification and noise correction.

Furthermore, the sensor incorporates digitisation circuits which allow the CMOS chip to directly output a digital signal (perfect for IP cameras).

The problem that lies herein, is because of the complexity of this design, the area of the sensor devoted to light capture is reduced, and as each pixel must perform its own conversion, image quality suffers.

Some may argue that cost is a main reason for the rise of the CMOS, however the production cost for both types of sensors are similar. The only cost factors that need to be observed, is that CMOS sensors sometimes require additional support chips to optimise image quality.

Source: austech.info