CCD stands for charge-coupled device; CMOS stands for complimentary
metal-oxide semiconductor. A CCD image sensor or a CMOS sensor is used in most
digital CCTV cameras. Capturing light and converting it into electrical signals is
the main task of the two types of sensor
A CCD image sensor is an analog device. These
are the chips onto which the light captured by a camcorder's lens is focused. Camcorder
processes those signals, then the image is recorded to the camcorder's storage.
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| CMOS VS CCD |
Neither
technology has a clear advantage in image quality. On one hand, CCD sensors are
more susceptible to vertical smear from bright light sources when the sensor is
overloaded; high-end frame transfer CCDs in turn do not suffer
from this problem. On the other hand, CMOS sensors are susceptible to undesired
effects that come as a result of rolling shutter.
CMOS can
potentially be implemented with fewer components, use less power, and/or
provide faster readout than CCDs. CCD is a more mature technology and
is in most respects the equal of CMOS, CMOS sensors are less expensive to
manufacture than CCD sensors.
Another
hybrid CCD/CMOS architecture, sold under the name "sCMOS", consists
of CMOS readout integrated circuits (ROICs) that are bump bonded to a CCD
imaging substrate – a technology that was developed for infrared staring arrays and
now adapted to silicon-based detector technology. Another approach is to
utilize the very fine dimensions available in modern CMOS technology to
implement a CCD like structure entirely in CMOS technology. This can be
achieved by separating individual poly-silicon gates by a very small gap. These
hybrid sensors are still in the research phase, and can potentially harness the
benefits of both the CCDs and the CMOS imagers.
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