Technical analysis of megapixels network camera

Technical analysis of megapixels network camera
With the continuous development and popularization of digital technology, the traditional analog surveillance visible has been unable to meet the demand of users see things clearly, highlighting the advantages of digital control, becoming a mainstream technology for future monitoring. It has a high-definition monitor, "attention to detail" and other features, and monitor high resolution the monitoring area covered by a wide range of the product on the market more and more industrial users, such as electronics, education, high-end residential, prisons, government departments and factories for major regional, import and export, real-time HD surveillance, license plate recognition, face.
HD trend, domestic and international security vendors have increased their efforts to production 720P, 1080P, 300-megapixel HD cameras products to market. IP digital surveillance based on TCP / IP networks, HD IP Camera products to enhance clarity at the same time, it also brings high bandwidth usage, the proliferation of storage space and back-end load increased, which gave the practical application of a lot of inconvenience; the cost of the hardware resources of a large number of inputs, and even the development of the system overwhelmed, high for high bandwidth, high storage, high CPU resources, based on the organic integration of the technological innovation of the front-end hardware and integrated management platform can radically reduce the troubled by the question. Then I will address these issues, discusses the response to high-definition brought decompression technology for high bandwidth, storage and other issues.
Technical Analysis
CROPPYING
CROPPYING also known as crop, installed in most outdoor scenes. Shown in Figure 1 car park, blue sky, white clouds in video surveillance elements not necessary, if the entire picture collection, transmission and processing will be a waste of resources; cropping technology within the camera through the viewfinder, crop, blue sky, clouds, etc. invalid image information Parking only to the effective image information is transmitted to the storage and display background, this trimming technique saves about 1/3 of the resources.
ePTZ
ePTZ said electronic PTZ, collected all the images in the screen to set the appropriate window, the window in full screen move freely, and even can be prefabricated bit is set, the window in accordance with the rules of time and stay jump turn on a fixed machine ball machine to achieve the effect, while in the window zoom distance. At the same time, this function only valid data output to define the window, ignoring the image information outside the window, both to meet the functional requirements of the PTZ operation, but also to achieve the effect of resource savings.
AAS
AAS also known as intelligent bandwidth throttling to start AAS function when the video monitor screen is at rest, the frame rate from the original set of 30 frames / sec to reduce a / s in the test, and when the video monitor screen objects appears, and the frame rate will be quickly restored to 30 frames / sec, the bandwidth variation of the process is only about 3MBPS, as shown in Figure 3. I have tried to understand the function of motion detection, the conventional motion detection is mainly used in the switch whether to start recording, there is only "yes" and "no" two states. Intelligent bandwidth adjustment technology, the frame rate is reduced when the device is in the "quiet" state, storage, real-time browsing and screen is ongoing, and the frame rate is triggered quickly restored to the default value, no delay video data stream. Time of moving objects in the scene of the practical application of about 1/10, the use of the technology can save 4/5 for the entire system resources.
Multi-stream
Multi-stream commonly known as multi-stream in the IP Camera video settings page for the stream output four groups of independent, four different computers to access the camera pre-set 4 stream, 800 million (5 frames / sec), 1080p (25 frames / sec), 720P (30 frames / sec) and 800 x 600 (15 frames / sec), each client can be synchronized received a pre-set code stream . The technology is to be achieved in the environment of a variety of application requirements, the camera can provide multiple independent stream selected at the same time, and can also reduce network load and pressure. Such as storage 500 million, on the TV wall with 720p, Client Access with 1080P, mobile user to select CIF or QCIF smaller resolution, no effect can simultaneously send each other. Thus avoiding the HD IP Camera is only one choice, no matter how many users access only to provide a single 1080P resolution screen selection, while output multiplexers, duplicate resource consumption, to large-scale high-definition applications is disadvantageous, as shown in Figure 2.
Wisdom-stream
Wisdom-stream and interpreted as a compensatory enhancement of key positions, sometimes in a conventional screen, the user only concern a part of the screen, only to ensure that key positions clear, while the other part of the screen, users do not care, a fixed camera there is no way to do. Select the target area by Wisdom-stream streaming function, the user can check the focus, the picture quality to enhance the sharpness of the partial sacrifice other positions by a certain extent, in order to ensure the readability of the key information. This effect was originally the need for multiple HD IP Camera, installed in a different location, a clear picture of the global monitoring can be done, and Wisdom-stream by fewer cameras for key parts of the compensatory enhancement, on the other hand resource savings for users.
SVC
Literally translated as SVC scalable video coding, Crystal Core (Vivotek) proposed this idea and successfully achieve the network camera system. SVC radical improvement in the multi-stream limitations, to understand from both ends of the transmission, multi-stream technology users need different data sent from the IP Camera, the picture quality of the needs of different users / rate / resolution from network cameras made by the client is different, and the bandwidth is occupied. SVC technology application mode from the IP Camera side to obtain the complete data stream transmitted to the back-end of the Relay Server, and then by the Server according to the specific needs of the visitors, to provide a different picture quality / rate / resolution combinations data stream to access persons. SVC appears to solve the multi-stream "regret", but also marks the arrival of a new technological era of high-definition capture device.
The SVC + AAS ", combining the strengths
SVC + AAS is a combination of the application, before it comes to AAS in FREEZE moment only transmit an image, but the 25 in this frame and the moving image is the same picture quality and resolution. The SVC + AAS combination of applications (see Figure 5), even can adjust the transmission of still pictures a lower resolution and picture quality, which is a technological leap forward, to fundamentally change the traditional flow Media mechanisms, AAS can save 4/5 bandwidth resources, in combination with SVC application the AAS function is strengthening can be achieved "amazing" 9/10, on contractors, the user is undoubtedly great news.
Epilogue
Security vendors, it is based on so many advanced decompression technology that makes us always remain in the ranks of the state-of-the-art in the era of high-definition network video surveillance, and the ability to provide users with large-scale high-definition applications integrated solutions.
from:http://www.vstarcam.com/channel/Technical-analysis-of-megapixels-network-camera-122.html