CCD and CMOS are two different types of image sensors being used in digital camera. The reason of increasing popularity of digital cameras has been introduction of CMOS sensors as they are inexpensive leading to a drastic reduction in prices of digital cameras. While CCD stands for charge-coupled device, CMOS is an abbreviation of complimentary metal oxide semi conductor. Both these sensors employ different technologies and a comparison between the two is like comparing apples with oranges. But it is essential to know the difference between CCD and CMOS.
CCD and CMOS have their strengths and weaknesses and neither is necessarily superior to another. However, claims of superiority are often made by manufacturers involved in making one of the two types of image sensors. The objective of both image sensors is to convert light into electric charge and then process it into electronic signals.
In the case of a CCD sensor, the charge of every pixel is transferred through an output node to be converted to a voltage, buffered and sent off-chip as analog signal. Output uniformity is high and all pixel charge can be converted to light capture. In the case of CMOS, each pixel has its own charge to voltage conversion, and the sensor often includes amplifiers, noise correction and digitalization circuits so that the chip outputs digital bits.
Both CCD and CMOS were invented in 60’s and 70’s by Dr. Sawas Chamberlain. CCD became preferred technology as it was supposed to deliver superior images. It was in the 90’s that CMOS started to become popular with the development of lithography. Today it is CMOS that has become dominant because of being considerably cheaper than CCD and also because of equally impressive imagery.
Talking of differences, protagonists of CCD claim that they are more sensitive than CMOS chips and hence deliver better images in dim light conditions. They also produce cleaner images while CMOS chips are often associated with the problem of noise, which is a small defect in the image.
Supporters of CMOS chips contend that these chips are very inexpensive. This translates into much lower camera prices. They also consume much less power which means that you can continue to shoot for longer periods before having to replace batteries if CMOS is used in the camera.
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Summary • CCD and CMOS are names of image sensors used in digital cameras. • CCD is charge coupled device, while CMOS stands for complimentary metal oxide semi conductor. • CCD produces high quality images but is expensive to produce. • CMOS, being inexpensive has lead to lowering of prices of digital cameras. • CCD eats more power, while CMOS is less power hungry.
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