The wireless vehicle monitoring skills are followed by the development of video surveillance skills. Before the network is introduced, the vehicle monitoring products are mainly based on the imitation of standard definition. In recent years, following the rapid development of security IP, network HD has become the mainstream of shopping malls, the richness of camera functions and license plate recognition skills have been further developed, and the development of vehicle monitoring skills has been diversified and iteratively accelerated.
3G/4G and wireless vehicle monitoring skills
Because of the continuous movement of the vehicle, the wireless communication network skills have become the first choice for data transmission and handling of vehicle video surveillance. At that time, following the breakthrough of communication skills in the 3G/4G category, 3G/4G wireless mobile skills became the mainstream wireless communication skills of domestic shopping malls at that time. As a part of mobile monitoring, vehicle monitoring completes long-distance video reading, long-distance control, geographic location, voice intercom and other functions through 3G/4G network, satisfying customers' long-distance video inspection and long-distance emergency command requirements, and providing them with customers at any time. The wireless video surveillance service at any place is widely used in public security police police car inspections, mobile command vehicles, and financial escort vehicles. Together, in some special occupational constraints, wireless portable monitoring systems can also be used to satisfy users' needs.
For the internal mainstream manufacturers, the general vehicle monitoring system consists of three parts: the vehicle terminal, the 3G/4G network and the monitoring center. The vehicle terminal is a front-end device of the wireless vehicle monitoring system, and is generally secretly installed in various vehicles. The vehicle terminal device is mainly composed of various devices such as a wireless vehicle terminal, a tablet computer, a high-definition vehicle video recorder, an in-vehicle device bracket, and a device box. When the system is open, you can read pictures in real time through the tablet computer, control the car camera to scroll, and perform two-way voice intercom with the back-end monitoring center.
In the use of detailed examples, please refer to the use case of the vehicle monitoring system arranged by Hubei Forest Public Security. The whole plan is based on the use requirements of the forestry public security law of the Forestry Department, relying on the 3G/4G wireless communication network of the telecom operators to build a wireless audio and video transmission system covering the entire area under the forest public security. The car-mounted PTZ camera on the roof of 100 forest public security inspection vehicles can monitor the dynamic information of the legal scene in real time, and can also understand the traffic conditions of the road surface, facilitate the command of the forest public security inspection vehicle to select the best road, and complete the forest public security. Long-distance supervision of legal acts. In the event of a major incident, live broadcast or video file playback can be performed on the 3G/4G network. The command center and the field personnel can also perform voice intercom through wireless transmission equipment to facilitate emergency command and complete long-distance visual command.
Wireless vehicle monitoring reference skills
In the face of customers, although the focus of the main product skills characteristics of different businesses, but many security and non-security skills requirements are very different, and many of the features and skills presented, after a period of time in the mall It presents products of the same skill utility type. When distinguishing between the quality of the wireless vehicle monitoring products and their functions, it is necessary to judge the skills indicators from the following points.
H.265 codec skills
The newly upgraded H.265 coding skills are compared to H.264 under the same image quality, and the H.265 encoded video size will be greatly reduced, further improving the wireless picture transmission experience.
1080P real-time video surveillance
The front end can be connected to 1080P high-definition car video recorder for real-time video monitoring, and the wireless vehicle terminal supports real-time video long-distance reading, which can monitor HD vehicle video in real time in the monitoring center.
Video storage playback
The wireless vehicle terminal has a car hard disk and supports high 1080P HD storage, which facilitates front-end storage and saves network resources. When recording, you can choose whether to bring audio video. Car video can be long-distance query and download, video file download speed can be equipped, support disk Proactively correct when abnormal, support the alarm when the disk is abnormal.
When the monitoring point is abnormal, the on-board alarm linkage is mainly an external alarm device, that is, the driver can report to the monitoring center in the event of an emergency during driving, and can make a two-way voice call.
The built-in GPS module can report the GPS geographic location information of the vehicle and complete the tracking of the vehicle's motion track to fully understand the vehicle's motion status. Historical video playback can show the track of the vehicle running together, and can also expand the bucket positioning.
It can capture the scene picture in front and save it on the car hard disk for easy tracking. The capture can be captured by three methods: alarm linkage, motion detection, and switch alarm.
It can supply 1 channel of two-way audio codec input and output, and can perform two-way voice intercom with the back-end monitoring center.
Active sleep, long-distance wake-up
The device can set the active sleep function. When there is no video stream transmission, the device does not have the code stream transmission within five minutes by default, then disconnect the 3G/4G network to save the tariff. If the wake-up device is online, the phone and SMS can be used to wake up the front-end sleep device. Supporting the method of making a call and sending a text message to the SIM card of the device triggers the device to go online. As long as the phone number added to the phone and SMS white list is added in advance, it has the right to activate the 3G/4G network connection. Both the phone and SMS whitelists support up to 5 phone numbers.
Switch quantity activates the upper and lower line
The support switch activates the offline line. When the alarm occurs on the parallel port, 3G/4G goes online. After the parallel port alarm is recovered, 3G/4G goes offline, which saves the tariff.
Vibration reduction planning
Because the vehicle will be shaken and sensation during operation, the equipment has a certain impact on the equipment. In order to ensure the normal and stable operation of the equipment, the audio and video input and output interface and power interface of the equipment are all selected from the aviation plug to ensure the interface is strong. It will be loose, built-in wire rope shock absorber, and the hard disk is placed on the shock absorber. It can be used to resist the horizontal and vertical shake to ensure the reliable operation of the hard disk and the video material is intact.
Code stream bandwidth adaptive skills
Because of the characteristics of the signal transmission of the 3G/4G network itself, the narrow bandwidth, easy to disturb, unstable and other factors will cause the wireless bandwidth to fluctuate up and down. For this reason, Keda has launched the independently developed KWTP wireless transmission protocol to do the transmission of the code stream. The guarantee of reliability can be actively adjusted according to the network conditions at that time, which improves the stability and power of video and audio transmission.
HD portable PTZ camera
The high-definition portable infrared PTZ network camera is used as a mobile video collection source for wireless portable image transmission devices, and supports 1080P resolution. It contains a replaceable battery module to complete the self-power supply, and the built-in WiFi module can transmit the collected and encoded pictures to the portable host. Thanks to the five powerful magnets at the bottom, it can be attached to the surface of any magnetizer, and the device method is more diverse.
Large capacity battery powered
The wireless portable image transmission device has built-in 16AH large-capacity rechargeable battery, which can be used by the portable host for more than 12 hours. Together with the external device feeding emergency, it can also supply “UPS” to power the portable PTZ camera and tablet. .
The modular planning of the vehicle host is that each key module can be plugged and replaced, for example, the wireless module is pluggable, and the hard disk is also pluggable. If it is not modular, for example, under the 3G wireless communication protocol, I bought a DVR, but if I move the 4G rendering, then when I replace the original device, I have to replace it all, not just to replace a module. .
Anti-shake and fog-passing skills need to be improved
Because the environment in which the car camera is used is not fixed, the environment encountered is also complex and changeable. Urban roads, village roads, mountain roads, etc. are all possible, causing the in-vehicle camera to move inevitably. It is necessary to take into account the effects of the vehicle's shaking and shaking, as well as the clarity of the picture in inclement weather conditions such as haze.
At that time, the camera's anti-shake skills have not been a very good solution in the industry, relying on the algorithm to achieve the stability of anti-shake, other manufacturers on the lens are doing the test, but the role remains to be further examined. There is no difference between the fog-passing skills of on-board monitoring and the fog-monitoring skills on the ground. At that time, the more advanced fog-passing skills were based on “optical + algorithm-through fog” as the mainstream skill. For this third-generation fog-passing skill, different manufacturers have different skills. Understanding. In summary, in addition to the hardware and equipment of the camera itself, we must first look at the good and bad of the fog-transparent algorithm among various brand manufacturers and the effect of fogging in practical use cases. Digital fog can preserve the original color of the picture, and the picture can be restored slightly worse than the optical fog. Optical fogging is because of the use of infrared imaging, the picture can be restored. After participating in the third generation of fog-passing technology of the algorithm, the fogging effect can be better, and the image is still clearly visible under dense fog.