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Wide Dynamic Surveillance Cameras Ccd / Cmos + Dsp Resolution

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#1 iacemomo


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Posted 08 August 2012 - 02:01 AM

Wide dynamic surveillance cameras CCD / CMOS + DSP resolution
Wide dynamic camera until now, what has gone through several generations, could not speak clearly. In terms of technology, not backlight compensation technology, wide dynamic There are two kinds of important realization method: CCD + DSP technology and CMOS + the DPS technology.
CCD + DSP technology:
The DSP chip is a special microprocessor, based on mathematical models and algorithms of digital signal processing theory to design a dedicated digital signal processor chip. Calculation procedures for all "hardened" and other equipment needed by the digital filter is also integrated all hardening, such as adder, memory controller, input / output interface, and even other types of external devices. Can not be carried out in the analog signal processor, digital processing, such as two-dimensional digital filtering, digital dynamic image detection, digital backlight compensation, color contour correction, detail compensation frequency adjustment, accurate color matrix accurate calibration, auto-focus.
The super wide dynamic often use double speed CCD with DSP approach. The core of this double exposure (or shutter) is the larger scene of light and dark contrast, the camera first, the bright area to conduct a rapid exposure, a bright area clear and normal images and stored into the data buffer memory; The dark area in the scene, did a slow exposure to get a clear picture of a dark region of image is also stored in the data buffer memory. After the exposure is completed, the use of DSP unique image processing algorithms, two images of which brightness to the appropriate parts cut off, the final image superimposed on the synthesis and output a light and dark areas are clearly visible. This will avoid bright areas overexposed and dark underexposed problem, so that the entire screen are clearly visible, in order to achieve wide dynamic treatment effect. However, if a different DSP chip, there are still significant differences in specific details, such as sensitivity, color reduction, white balance processing.
CMOS + DPS technology
Pixim's technology foundation for the development of Stanford University in the 1990s developed a DPS (digital pixel processing system) based on CMOS technology, the new image pickup system, this system through its super wide dynamic capabilities to obtain high-quality picture. Wide dynamic function of epoch-making to enhance the image shooting of an image of bright and dark areas can achieve a more realistic, sharper images than CCD. Wide dynamic handling, DPS is a single pixel exposure and ARM7 control technology, the double exposure compared to the CCD imaging has a higher dynamic range. Numerically speaking, the DPS technology, the CMOS camera on the current processing technology, the dynamic range can be reached 95dB, even to 120dB. Expand the dynamic range at the same time, DPS also solve the deficiencies of the CCD sensor in the processing of dynamic range and color authenticity, more realistic color reproduction, to meet the application requirements. Camera using this technology in the digital image sensor in each pixel are using an analog-digital converters (ADCs) to capture the optical signal directly into a digital signal, to minimize attenuation of the signal in the arrangement and interference.
DPS technology reflects the wide dynamic function of epoch-making to enhance an image of bright and dark areas of image shooting, you can achieve more realistic, sharper images than CCD. Double exposure DPS using a single pixel exposure and ARM7 control technology, compared to the CCD imaging has a higher dynamic range. DPS, each pixel processing technology alone to solve the problem of the CCD sensor dynamic range, color reproduction is insufficient.
But also be noted that the DPS is based on each individual pixel processing technology, because each pixel contains a complete set of processing circuits, and thus greatly reduce the sensitive area of ‚Äč‚Äčeach pixel, that is to reduce the amount of light, the The results are based on CMOS and DPS technology, the camera sensitivity is a significant effect or not satisfied.
Contrast CCD Wide Dynamic Epps as Marketing Manager Fan Qinghua said: "It is worth noting that due to the inherent characteristics of the CCD, even using multiple exposure CCD camera a wide dynamic range up to only 66dB, while CMOS wide dynamic camera It is reported that its dynamic range is 120dB above there will be more room for development in future CMOS wide dynamic technology. "
As a very wide dynamic camera, in the technical aspects of the development is bound to strive for excellence. In short, the only wide dynamic technology, continuous improvement in order to more users, so all households.

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