Tips for selecting vehicle monitoring system

Generally speaking, the main basis for evaluating the merits of a vehicle-mounted DVR (MVR / MDR) system are stability, shock resistance, heat resistance, and miniaturization.
The platform of the vehicle-mounted system generally adopts the Vx-Works real-time operating system. It is specifically designed for embedded systems and has a wide range of applications in industry and military, including Mars control sensors that land on the surface of Mars. Unlike Windows and Linux systems, the stability of Windows systems has always been questioned. It takes up system resources and is vulnerable to attacks. Linux systems are free software and there is no special maintenance. In the selection of CPU, the application of Freescale's Power PC communication level, this CPU supports multi-task parallel processing. This kind of CPU is widely used in industrial, communication and military fields. The world's first pure hardware audio and video MPEG4 compression / decompression chip VWeb2010 is used on the decoding chip, which is different from the compression algorithm + DSP chip on the market. This processing mode can provide high-definition DVD quality and support From CIF to D1 video format, to ensure real-time synchronization of audio and video.

Build a stable platform of vehicle-mounted DVR based on the above technical foundation, and realize the recording and recording of the car's live images (road signs, vehicle pedestrian conditions) or internal live images (seats, passengers and passengers) while the vehicle is driving; provide a variety of convenient queries and playback Mode, you can view and playback the recorded live images, and achieve high-speed backup of the video data through the USB2.0 interface. In the system power supply link, considering the complexity of the current power consumption in various vehicle environments, usually two sets of voltage ranges of 9 ~ 40VDC and 40 ~ 80VDC are used to meet various mobile vehicles. Problems such as voltage fluctuations and electromagnetic interference in the process ensure reliable and stable operation of the system.

The basic components that make up a set of digital vehicle monitoring system are: vehicle-mounted hard disk recorder, camera, monitor and transmission line. The camera is responsible for obtaining the video signal in the car, and transmitting the image signal to the car hard disk recorder through the video coaxial cable. The hard disk video recorder compresses the video signal and stores it on the hard disk according to the set compression format. At the same time, the hard disk video recorder can also output the various video signals to the monitor for display according to the combination mode selected by the user.

Depending on the model selected by the user, the functions of the car hard disk recorder are different. Car DVR should have the following basic functions:

1. Professional power supply design to adapt to the working environment with large fluctuations in the power supply voltage of the car and large electric pulse impact.
2. Professional hard drive shock design, can be locked and removable, providing convenient data backup function.
3. Using an embedded operating system, it is stable and not easy to crash, and the incoming call quickly starts recording.
4. Support multi-channel audio and video input for real-time monitoring and recording.
5. Multi-mode recording function (manual, timing, alarm linkage, dynamic detection) and fast query playback function.
6. With video loss and dynamic detection alarm function.
7. Three-level user management mode, safe and reliable, and high density.
8. Support large capacity hard drive, plug and play without formatting.

In addition to the above basic functions, the on-vehicle hard disk recorder should also have powerful function expansibility and be able to provide different expansion functions according to user needs. According to the different models selected by users, the extended functions supported by our products are:

The vehicle has a black brake function to record the driving process of the vehicle; GPS global satellite positioning system and electronic map navigation function.

Real-time, two-way information wireless broadband transmission function, realizing remote real-time monitoring and dispatch management; car entertainment function, providing video and audio data playback function, can be used to play advertisements, entertainment programs, etc. in the car.

Let us first compare the situation of the three mainstream video signal processing and recording equipment for car DVRs on the market:

All video signals are input to the on-board hard disk recorder for processing. The video compression format supported by the system is different depending on the model of the hard disk recorder selected by the user. At present, the main video image compression formats on the market are: M-JPEG (motion JPEG image), MPEG1, MPEG2 and MPEG4.

The functions supported by the car DVR include: compress and record video images as video files, randomly retrieve video files, preview video files and backup video files, (when previewing files, support fast forward and rewind of images) with black box function, cloud mirror Control function, alarm function, another function expansion (entertainment program playback, advertising playback, etc.).