Technical Characteristics And Development Advantages Of Network Camera

In terms of hardware structure, the webcam integrates the video compression and network transmission processing module on the basis of the analog camera, so it has the technical characteristics of both the analog camera and the video server, but it is not a simple combination of the two. Its unique structural design and implementation method determine that it has its own technical characteristics. From the perspective of data flow, the network camera is: lens->sensor->isp-> encoding chip - > network. To build a network camera, from real video capture to code stream transmission, many factors need to be considered, including image quality, video acquisition, selection of encoding and decoding chip, compliance scale, network transmission, network security, etc.

Technical features of network camera

In terms of hardware structure, the webcam integrates the video compression and network transmission processing module on the basis of the analog camera, so it has the technical characteristics of both the analog camera and the video server, but it is not a simple combination of the two. Its unique structural design and implementation method determine that it has its own technical characteristics.

1. Video compression

Video compression is the most basic technical requirement of network camera. At present, the video processing chip of network camera is mainly ASIC, and the video compression adopts MPEG-2, M-JPEG, MPEG-4 and H.264, among which H.264 is the mainstream. Recently, the network camera based on tidavinci chip has been put on the market. DaVinci is a SoC system, which has the characteristics of efficient ASIC processing and takes into account the innovative flexibility of CPU and DSP. It has an ARM9 subsystem in addition to the main processing system of DSP. Another important feature is that it has extremely rich interfaces, which are quite useful for the function development of network camera, Some of the following features are based on this feature.

2. Highly integrated

The network camera has not only the image acquisition function of the traditional analog camera, but also a front-end processing system. It has quite rich heterogeneous bus access functions, such as VoIP, alarm, 232/485 serial device access, etc. in addition, it can also send alarm signals such as motion detection, video loss, lens covering, abnormal storage, etc. to the back-end through the network. The network camera can be embedded with a storage system. SD card is usually used. At present, the capacity of SD card ranges from 8MB to 4GB. SD card can be used as a temporary storage device for images in case of network failure. After the network recovers to normal, the video can be uploaded, which can effectively ensure the continuity and integrity of video data. Another use of SD card is to store important alarm images locally and upload them to the back end at the same time, so as not to cause the loss of video data due to the unreliable transmission of the network.

3. Power over Ethernet (POE)

Poe is a network power supply technology with rapid development and wide application in recent years. POE (poweroverethernet) refers to the existing Ethernet cat 5. Under the condition that the cabling infrastructure is not changed, it can not only transmit data signals for some IP based terminals (such as IP phones, network cameras, etc.), but also provide DC power for such devices. In this way, the webcam does not need to be powered by other power supplies. The centralized use of UPS (uninterrupted power supply) can ensure the uninterrupted operation of the equipment for a period of time (depending on UPS), and also simplify the management. IEEE802.3af standard is a new standard based on Poe, which requires that the power consumption of equipment powered by Poe should not exceed 12.95w.

Nowadays, most network switches provided by manufacturers support Poe. If the corresponding general switch equipment has been installed, the POE function can be realized by adding a midspan to the switch. The midspan is mainly used to load power to the network cable.