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  • HD IP surveillance camera image sensor characteristics


        HD IP camera from the purported speaking beyond conventional analog cameras. HD surveillance cameras are now available in the market has formed a pattern of diversified products megapixels 2,000,000 pixels 3,000,000 pixels for the pilot. One IP HD network camera video capture, video encoding, network transmission of several parts. HD IP cameras can be seen as a combination of a high-definition video camera and a computer. Progressive scan CMOS / CCD photosensitive optical signal is directly able to capture images and single-chip SoC processing, direct transmission over an IP network, allowing the user to standards-based IP network infrastructure in local or remote locations achieve viewing, storage and management of high-definition video data.
        The high IP cameras to the core member of the image sensor (ImageSensor) do the words of the classification, a CCD and CMOS. CMOS subdivided into traditional CMOS and ExmorCMOS of that back-illuminated CMOS. CCD and CMOS, the basic structure and working principle, the differences are as follows:
        CCD is ChargeCoupledDevice (Charge Coupled Device), which is a semiconductor imaging device, and the stored charge of the CCD charge-coupled device information required under the control of the synchronization signal, a one embodiment read after transfer, transfer and reading of the charge information take the output needs of the clock control circuit, and three groups of different power cooperates, the whole circuit is more complex.
        CMOS is an abbreviation of ComplementaryMetal-OxideSemiconductor (complementary metal oxide semiconductor) and CCD with HD cameras record light changes semiconductor, CMOS photoelectric sensor directly after photoelectric conversion produces a current (or voltage) signal, the signal read very simple, the following features of both.
        CCD charge-coupled device is required under the control of a synchronous clock, in units of a one to output information, the slower;
        CMOS optical sensor of the optical signal can be taken out the electrical signal, and can simultaneously process the image information of the respective units, the speed is much faster than a CCD charge coupled device;

        Most of the CCD charge-coupled device requires three power supply, power consumption is larger ;
        CMOS photoelectric sensors only need to use a power supply, the power consumption is very small CMOS photoelectric sensor has a great advantage in energy efficiency.
        HD IP camera´s "brain": core processing chip
        HD IPC design, but architecture, consist primarily of two types: First, using a CCD / CMOS sensor as the image acquisition devices, SoC chip supporting realize image processing and encoding functions; Second, the use of front-end surveillance camera module as image acquisition devices, and a generic ASIC or DSP coding and transmission. As the first flexible architecture design, widely used by manufacturers to adopt.
        There are three implementations in the area of ​​image processing: the first program dedicated ISP processing chip and coding processing part of the program is more flexible the dedicated ISP chip stability, to ensure the quality of the image; second solution with integrated the ISP encoder chip, the program flexibility inferior to the first option, and a dedicated ISP chip stability, high image quality, high cost; third option such as FPGA chip signal processing and coding functions The program flexibility strongest, but poor stability, cost and the highest image quality is difficult to guarantee. Dedicated ISP program design is flexible, cost-effective, can guarantee the quality of the image, apply to the design of the high-definition IPC.