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Section 4: CCTV system: What is the image sensor?
Section 3: Principle of camera
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Section 1: What is CCTV system?
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Section 4: CCTV system: What is the image sensor?
Meper, 25-09-2015
What is the image sensor?
What is the image sensor?
Components image sensor in the camera is functioning image signal converted into an electrical signal
The image sensors commonly used today is the CCD sensor technology (Acronym of English words: charge-coupled devices) and CMOS sensor technology (Acronym of English words: complimentary metal-oxide-semiconductor).
1. CCD image sensor (charge-coupled devices):
As one of the oldest technology of digital cameras, with image quality superior to CMOS thanks sensitivity frequency range and better noise control, however disadvantages of CCD is power consumption Too much.
The principle of operation of the CCD:
CCD (Charge Couple Device - means "charge-coupled components"), implemented to transform light into electrical signals by the photodiode and support vessels. Figure 1 is a block diagram of the principle activities of CCD in the camera, including:
After the last light RGB color filter (Bayer filter) shall be included in the array of pixel RGB CCD image sensor. To clarify, we imagine this: The photons are converted into electrons, then the electrons will be converted into analog voltage signal. The analog signal after amplification will take over the ADC (Analog Digital Converter) to convert to a digital signal (Digital)
Figure 1: The principle of operation of CCD
Figure 2: The image's actual CCD chip
2. The CMOS image sensor (metal-oxide-semiconductor ticomplementary):
CMOS image sensors have lower image quality than CCD, but thanks to the new technology breakthrough now makes quality of modern CMOS image sensors become equal or even surpassing the standards of CCD. With many features built than CCD, CMOS image sensors more efficient operation, less power dissipation and high speed shooting better than CCD.
Figure 3 illustrates the principle of operation of the CMOS image sensor:
After the last light RGB color filter (Bayer filter), it will still have three basic colors R (red), G (green), and B (blue). Light with these colors will touch the pixels of the pixel array (array pixels) make up the electrons with different densities. These electrons are converted into analog voltage levels vary through the exposure of the CMOS. Analog signal after amplification will be taken to the ADC (Analog Digital Converter) to convert to a digital signal. Thus the principle of operation of CCD and CMOS image sensors are almost identical, differing only in technology converts photons into analog electrical signals only.
Figure 3: The principle of operation of the CMOS image sensor
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