Analysis of high-definition surveillance cameras night vision problems and breakthrough

Analysis of high-definition surveillance cameras night vision problems and breakthrough
Since 2010, after two years of market cultivation, high-definition camera is from the "trend" into "reality". Many HD IP Camera manufacturers have sprung out of the traditional analog camera manufacturers have gradually transition to high definition. In the market, more and more agents, contractors and authorized users HD. It can be said that since 2012, high-definition cameras began to usher in the peak period of development.
Specifically, despite still being generally referred to as "millions of high-definition, but the clarity of high-definition camera has been greatly improved, the pixels from 600000, 1300000, 2000000-5000000 increments, and some manufacturers even Claims pixel level has been raised to 20 million; has been rapid development in the mode of transmission, IP and HD-SDI, and each occupies a small market share. In addition, in terms of color reproduction and smart analysis, millions of HD IP Camera has been greatly improved.
But because the technology is not mature enough, high cost and other factors, mainstream applications of the high-definition camera products focused on the government, banks and other high-end market, other areas still analog products. Which HD cameras commonly used CMOS chip, lower color saturation, texture and sharpness performance is slightly inferior, shooting in low light at night, often less than ideal. Based on this, some manufacturers introduced HD 960HCCD network products, Sony Effio-EN700 line program, low light, pure digital interface, image pixels of about 600,000, not only during the day, high-definition shooting night clear color imaging, solution to the problem of millions of HD IP Camera night vision.
Limitations of CMOS HD camera
The so-called CMOS, i.e. complementary metal oxide semiconductor, the master is made of silicon and germanium semiconductor by the negatively charged and positively charged CMOS transistors to implement the basic function. With a CCD (charge-coupled device is a from the image semiconductor electronic organization up method), they are used in image semiconductor sensor, it is a PN semiconductor can convert light photons combination Be into a proportional number of electrons. However, in order to distinguish the two, we habitually called the CMOS sensor or CCD sensor, but does not indicate the method of processing images.
Compared to CCD sensors, CMOS sensors do not require complex signal processing, direct image semiconductor electron into a voltage signal, in a short period of time to deal with large amounts of data, the output of high-definition video, and therefore adapt to high-definition camera needs . Advantage of the high level of integration, the automatic gain control, automatic exposure control, gamma correction, backlight compensation and automatic shading correction is far stronger than the CCD sensor. Meanwhile, in order to make the image easier to carry out network transmission, camera manufacturers are constantly improving the processing efficiency of image compression coding. Today, 1.3 million pixel HD IP Camera (720P) chip technology, CMOS position of absolute dominance.
However, in terms of sensitivity, the human eye can see 1Lux illuminance (Clear Night Setting) is equivalent to the full moon following objectives; CCD sensor is only slightly better than the human eye, between 0.1 ~ 3Lux; CMOS sensor sensitivity ships in the 6 ~ 15Lux, equivalent to the CCD sensor 1/10 ~ 1/3, the noise up to nearly 10 times of the CCD sensor. Therefore, in the night low-light environments, CMOS cameras is far less than the CCD sensor. While the CMOS sensor has done a very large sensitivity CCD sensor, but the requirements of the DSP processing speed is very high, virtually pulled up the price of a CMOS camera, short term large-scale applications.
The future, with the step-by-step solution of the problem of network bandwidth, both the cost of large-scale construction and upgrade and maintenance convenience and other advantages million HD IP Camera to a wider range of applications, and even become the mainstream of the surveillance cameras. But for now, the night vision technology is not yet mature, coupled with higher costs, which greatly restricted the popularity of HD IP Camera.
For most users, the night periods of high incidence of crimes of all sorts of events, which is the key period of the security video surveillance. Select a poor night vision cameras, video surveillance will in time be a great blind spot, unable to meet the requirements of 24x7 security. But on the other hand, users see more clearly "as well as remote monitoring, intelligent analysis of the demand is equally pressing. This requires the camera to find a balance, and can not simply return the old analog cameras on during the day and night shooting. Thus, 960H network HD technology into the field of vision of the camera manufacturers.
SonyEffio-EN night vision principle of the program
In 2009, Sony Corporation of Japan launched Effio-E program, the official standard of the program is: 4127 +4816 +673. Through the Effio-EDSP with the 960HCCD (EXviewHADCCD Ⅱ) with can reach 700TVlines standard resolution the image pixels 600,000 pixels (pixel). Compared with the previous program, it can provide a clearer picture, better color saturation and brightness.
One of the most advanced chip technology as the field of analog camera, Sony Effio-E program has the advantage of high-resolution, high signal-to-noise ratio and high color reduction degree of the "three high". Demonstrate the finer images in the electronic zoom, and 3D noise reduction technology, effectively reduce the image noise in low light conditions to maintain the sharpness of the image. Coupled with a higher degree of color reproduction, a wide range of automatic white balance adjustment and partition compensation function effectively improve the details of dark areas and overexposed loss, to ensure the integrity of the recorded image.
In practical applications, Sony Effio-E program cameras often with infrared-definition lens, excellent image detail, color reproduction is real bright, bright, no color cast, and the image is sharp, light luminance processing ability, with a realistic sense of depth, the maximum to achieve the imaging screen of the day / night. At the same time, the use of the latest generation of dot-matrix LED light source (IR the Ⅳ technology), the photoelectric conversion efficiency, lower power consumption; with intelligent optical technology, infrared light and white light at the same time fill light, night vision pure color effects can be achieved.
In 2012, Sony Effio-E program upgrade, Effio-EN program came into being. Compared with Effio-E program, the new DSP image quality, sensitivity and color saturation tends to be more perfect. Especially in the transmission mode, the upgrade from analog transmission to digital transmission, a qualitative breakthrough in image fidelity.
The use of digital signal transmission
In the signal transmission process, the traditional analog cameras must, through the sensor optical signal is converted into an analog electrical signal, and then converted into a digital signal to analog to digital conversion and chrominance and luminance processing, then the digital signal is analog-to-digital conversion and modulation PAL / NTSC system standard analog video output signal arriving at the DVR and other back-end device, by the video capture chip analog signal is converted into a digital signal. 3 times in this process, of the AD conversion, and may cause damage to a certain degree of quality. When the camera SonyEffio-ENF program, this transmission mode has been unable to meet the requirements.
Therefore, some camera manufacturers to improve the transmission mode of 960HCCD camera in the camera's built-in network module, pure digital interface, eliminating the need for the signal the compression conversion link, to enhance the transmission speed, and to avoid damage to the signal transmission process . , And millions of HD IP Camera in transmission mode and back-end with the sharing of resources.
Analog cameras still occupy most of the market share, especially in high-definition CMOS HD camera technology is still not mature enough, the cost can not be rapidly declining situation, analog video surveillance will continue to exist for a long time. Although the government, banks and other high-end market, high-definition camera is the first application of the plot, shop, small supermarket, office buildings and other small and medium-sized monitoring system, analog cameras is still a high cost option.
But should also see that China's security monitoring the transition to high-definition video surveillance from analog video surveillance, users "see more clearly" as well as remote monitoring, intelligent analysis of the increasingly high demand for analog camera market share will be gradually reduced, Megapixel IP cameras represent the future of the industry. During the transition period, 960HCCD HD IP Camera with day and night equally outstanding advantage is expected to be more widely used in the industry accounted for the majority of small and medium-sized surveillance. Entered the high-definition era, its night vision technology to bring HD IP Camera manufacturers inspiration.
From:http://www.vstarcam.com/channel/Analysis-of-high-definition-surveillance-cameras-night-vision-problems-and-breakthrough-84.html
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