Q:What different between CCD & CMOS image sensors?
‧A:
The
image sensor of the camera is responsible for transforming light into
electrical signals. When building a camera, there are two possible
technologies for the camera's image sensor:
-- CCD (Charged Coupled Device)
-- CMOS (Complementary Metal Oxide Semiconductor)
CCD
sensors are produced using a technology developed specifically for the
camera industry, while CMOS sensors are based on standard technology
already extensively used in memory chips, inside PCs for example. CMOS
sensor is a kind of sensor that is normally 10 times less sensitivity
then CCD sensor. As human eye can see object under 1 lux illumination
(full moon night ). CCD sensor normally will see better or as good as
human eye in the range of 0.1 ~3 lux and are 3 to 10 times more
sensitive then CMOS sensor
-- CCD technology
CCD
sensors have been used in cameras for more than 20 years and present
many advantageous qualities; among them, better light sensitivity than
CMOS sensors. This higher light sensitivity translates into better
images in low light conditions. CCD sensors are, however, more
expensive as they are made in a non-standard process and more complex
to incorporate into a camera. In addition, when there is a very bright
object in the scene (such as a lamp or direct sunlight), the CCD may
bleed, causing vertical stripes below and above the object. This
phenomenon is called a smear.
-- CMOS technology
Recent
advances in CMOS sensors bring them closer to their CCD counterparts in
terms of image quality. CMOS sensors provide a lower total cost for the
cameras since they contain all the logics needed to build cameras
around them. They make it possible to produce smaller-sized cameras.
Large-sized sensors are available, providing mega-pixel resolution to a
variety of network cameras. A current limitation with CMOS sensors is
their lower light sensitivity
Article ID: 130, Created: July 14, 2009 at 1:37 PM, Modified: July 14, 2009 at 1:37 PM