Wireless on-board monitoring technology has emerged with the development of video surveillance technology. Prior to networking, the on-board surveillance products were mainly based on analog SD. In recent years, with the rapid development of security IP, network HD has become the mainstream of the market, and the richness of camera functions and license plate recognition technology have also been further developed, and the development of the entire vehicle-mounted monitoring technology presents a trend of diversification and iterative acceleration.
3G/4G and Wireless Vehicle Monitoring Technology Application
Because of the continuous movement of vehicles, wireless communication network technology has become the only choice for vehicle-mounted video surveillance for data transmission and management operations. Currently, 3G/4G wireless mobile technology has become the mainstream wireless communication technology in the current domestic market, with the breakthrough of communication technology in the 3G/4G field. Vehicle monitoring, as part of mobile monitoring, realizes remote video browsing, remote control, geographic location, and voice intercom functions through 3G/4G networks, and meets customers' needs for remote video viewing and remote emergency commanding, and provides them with application customers at any time. Wireless video surveillance services are widely used in patrols, mobile command vehicles, and financial escort trucks. At the same time, there are some special industry application restrictions, wireless portable monitoring system can also be used to meet user needs.
For mainstream manufacturers in employment, the general vehicle-mounted monitoring system consists of three parts: vehicle-mounted terminal, 3G/4G network and monitoring center. The vehicle terminal is a front-end device of the wireless vehicle-mounted monitoring system. It is generally installed in various vehicles in secret. The vehicle-mounted terminal equipment is mainly composed of wireless car terminals, tablet computers, high-definition vehicle-mounted PTZ cameras, vehicle-mounted mounting brackets, and equipment boxes. . After the system is turned on, it can browse images in real time through a tablet computer, control the rotation of the onboard PTZ camera, and perform two-way voice intercom with the back-end monitoring center.
In the specific case application, reference can be made to the application case of the vehicle monitoring system deployed by Hubei Forest*. The entire plan is based on the forestry office Forest* enforcement application requirements, relying on telecom operators 3G/4G wireless communication network, building a wireless audio and video transmission system that covers the entire forest area*. Install on-board special PTZ cameras on the roof of 100 forest* patrol vehicles, which can monitor the dynamic information of law enforcement sites in real time, and can also understand the traffic conditions of the roads, and can be used to direct the forest * patrol vehicles to choose the best route to realize the forest * Law enforcement behavior remote supervision and management. In the event of a major incident, the live broadcast or video file playback can be performed through the 3G/4G network. Voice intercom can also be conducted between the command center and on-site personnel through wireless transmission equipment, facilitating emergency command and realizing remote visual command.
Wireless vehicle monitoring reference technology
In the face of customers, although each business focuses on different product features, many security and non-security technical requirements are similar, and after a lot of unique features and technologies emerge, the market will soon be in a period of time. There are products of the same technical function type. In distinguishing the quality of wireless vehicle-mounted surveillance products and their functions, it is necessary to judge from the following key reference technical indicators.
H.265 codec technology
With the newly upgraded H.265 encoding technology, the video size encoded by H.265 will be greatly reduced compared to H.264 at the same picture quality, further enhancing the wireless graphics experience.
1080P real-time video surveillance
The front-end can access 1080P HD car PTZ cameras for real-time video surveillance, wireless car terminals support real-time video remote browsing, remote real-time monitoring of high-definition vehicle video in the monitoring center.
Video storage playback
Wireless car terminal has car hard disk, supports up to 1080P HD storage, convenient front-end storage, save network resources, video recording can choose whether to bring audio video, car video can remote query, download, video file download speed can be configured to support disk abnormalities It will be automatically repaired and the alarm will be reported when the disk is abnormal.
Alarm linkage
When an abnormality occurs at the monitoring point, the on-board alarm linkage is mainly an external alarm device, that is, the driver can report an alarm to the monitoring center in case of an emergency during driving and can perform two-way voice calls.
Location targeting
The built-in GPS module can report vehicle GPS geographic location information to track the vehicle's movement trajectory and fully understand the vehicle's movement situation. Historical video playback can show the trajectory of the vehicle at the same time, and can also expand Beidou positioning.
Image capture
Can capture the image of the scene in front, and then save it on the car hard disk for easy retrospective. Snap can be captured in three ways: alarm capture, motion detection, and switching alarm.
Voice intercom: Provides one-way two-way audio codec input and output, and two-way voice intercom with the back-end monitoring center.
Automatic sleep, remote wake-up
The device can be set to automatically sleep function. When there is no video stream transmission, the device defaults to no code stream transmission within five minutes, then disconnect the 3G/4G network to save the tariff. If the device wakes up, the available phone and text message wake the front-end hibernation device. Supports the triggering of device online by dialing a phone number and sending a text message to the device's SIM card. Only the phone numbers that have been previously added to the phone and message whitelist have the permission to activate the 3G/4G network connection. The white list for telephone and text messages supports up to 5 telephone numbers.
Switch activation online offline
When the number of switches is activated to go online and offline, and the alarm is generated on the parallel port, the 3G/4G goes online. After the parallel port alarm is restored, the 3G/4G goes offline and can save the tariff.
Shock-absorbing design
Because the road surface of the vehicle will bump and vibrate during operation, and it will affect the equipment, in order to ensure the normal and stable operation of the equipment, the audio and video input and output interfaces and the power interface of the equipment are designed with aviation plugs to ensure a firm interface. Will be loose, built-in wire rope shock absorber, hard disk placed on the shock absorber, can effectively resist the lateral bumps and longitudinal bumps, ensure the reliable operation of the hard disk, video data integrity.
Stream bandwidth adaptive technology
Due to the characteristics of signal transmission in 3G/4G networks, narrow bandwidth, easy interference, and instability may cause fluctuations in wireless bandwidth. For this reason, Kodak has developed a self-developed KWTP wireless transmission protocol to transmit codestreams. The guarantee of reliability can be automatically adjusted according to the current network conditions, which improves the stability and efficiency of video and audio transmission.
HD portable PTZ camera
High-definition portable infrared PTZ network camera as a mobile video acquisition source of wireless portable image transmission equipment, maximum support 1080P resolution. It includes a replaceable battery module for autonomous power supply, and the built-in WiFi module can transfer the captured coded image to the portable host. With the bottom 5 powerful magnets, it can be adsorbed on any surface of the magnetizer, and installation methods are more diverse.
Large capacity battery powered
Wireless portable video transmission equipment built-in 16AH large capacity rechargeable battery, portable host can work alone for more than 12 hours, at the same time in the emergency of the external device feed can also provide a "UPS" role for portable PTZ camera and tablet computer to supply power .
Modular design
The modular design of the car host is that each key module is pluggable and replaceable. For example, the wireless module is pluggable and the hard disk is pluggable.
And if it is not modular, such as in the 3G wireless communication protocol, bought a DVR, but the sudden movement of 4G appeared, then to replace the original equipment, it is necessary to replace the entire, not just a simple replacement of a module .
Anti-shake and fogging technologies need to be improved
Because the application environment facing the vehicle camera is not fixed, the environment encountered is also complex and changeable. Urban roads, country roads, mountain roads, and mud are all possible, causing inevitability in the process of moving the vehicle camera. Take into account the impact of jerking in the vehicle, and the problem of image sharpness in bad weather conditions such as haze.
Currently, the camera's anti-shake technology has not been a very good solution in the industry, relying mainly on algorithms to achieve stabilization of anti-shake, and other manufacturers are trying on the lens, but the effect remains to be further tested. There is no difference between the fog monitoring technology for on-board monitoring and the ground monitoring fogging technology. The currently leading fogging technology is based on the mainstream technology of “optics + algorithm foggingâ€. For this third generation fogging technology, different manufacturers have different Understanding. In general, in addition to the camera's own hardware configuration, it mainly depends on the pros and cons of each brand manufacturer's penetrating fog algorithm and the fogging effect in actual application cases. Digital fog can preserve the original color of the image, and the image reduction capability is slightly worse than that of optical fogging. Optical penetrating fog is due to the use of infrared imaging, image reducibility is good, in the third generation of fog through the addition of the algorithm after the fog can be better after the fog effect, in the fog is still clear imaging.
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