The so-called vehicle DVR recorder is the DVR that is with 1U standard framework, installed at the side of the car radio or near the postion of car CD player and linked with 1-4 channel videos to monitor and record all driving conditions during traveling. At present, the video compression method of vehicle DVR recorder are mainly MPEG4 and H.264.
Vehicle DVR recorder manufacturers have given this kind of embedded DVR used in car a nice name，MDR (Mobile Digital Recorder) or MVR(Mobile Video Recorder).Accordingly, The feature of "Mobile" becomes the biggest difference between vehicle DVR recorder and ordinary DVR. It's the mobility of vehicle DVR recorder that provides good conditions for security monitoring and controlling during vehicle's traveling.
Can all ordinary monitoring DVRs be used in Car? The answer is not. Although the embedded system thatvehicle video recorder use is same with that of ordinary DVR, it's more complicated in technology than the ordinary one and different in the key point of demand solution because while the vehicle is moving, it is suffering the problems, such as shock, dust, large power capacity,etc unavoidly, which destines the application environment of vehicle video recorder is worse than that of ordinary DVR.
Despite of bad Environment inside car, integration of multitechnology assures the success
To our knowledge, in order to ensure that vehicle can still realize smooth storage while moving, the manufacturers enhance the technologies, mainly including anti-shock, current stablization, heat dissipation, wireless transmission,etc. Perfect integration of these technologies is to further improve the stablity of video storage for vehicle video recorder.
Anti-shock
For the difference of road and vehicle conditions, anti-shock technology becomes the fudermental requirement tovehicle digital recorder and includes various anti-shock processes: machine shock absorption, hard disk bracket shock absorption, hard disk shock absorption,etc.,to achieve the result of whole vehicle's anti-shock.
During these anti-shock processes, shock absorption of the hard disk is the most important. It's because that hard disk the the easiest damaged component of vehicle video recorder and if hard disk is damaged, it's unable to record and store the situations inside the car. Therefore, the absorption of the hard disk is particularly important.
Regarding the methods of shock absorption seen on the markets, spring and rubber cushion are mainly used as the structure of anti-shock materials. Although some effect works at the upright direction, actually the viberation direction is irregular under driving state(especially under the bad road conditions) and prolonged use will leads to accident occurence of the equipment inevitably. Spring and rubber cushion can not absorb the energy of shock. Instead, they'll store this kind of energy till some extent and cause greater rebound. As is introduced, there is a method of adding oil sac inside rubber cushion, which mainly uses the advantage that compression of oil is smaller than that of air to achieve better effect of shock absorption.
Besides, for vehicle digital recorder, some manufacturers make the designs of hanging hard disk or cabinet to avoid shock, under which the whole hard disk or cabinet stays "vacant" situation to achieve effect of shock absorbption.
Stabilized voltage power supply
In addition to anti-shock, another important technique of car DVR is the stablity of power supply. Due to brake, climbing and ignition during the process of car's moving, these actions will cause the output voltage produce different amplitude fluctuations, which will lead to the vehicle equipment burned out easily. Thus, vehicle digital recorder itself must have the capacity of wide range voltage input to adapt to the change of the voltage.
Heat Dissipation
To our knowledge, when travelling on the road,vehicle will have large temperature variation. On most of vehicles, car DVR recorder is installed under or at the top of the driver's seat where is a closed space. Therefore, it raises high requirement for the use performance of car DVR recorder.
However, some people in the industry think that due to the detailed requirement and relevant document offered by some national or local governments for GPS location system, many transportation firms are equipped with GPS location system mandatorily. Hence, adding GPS location function to vehicle video recorder is more in line with the need of vehicle.
Future: storage becomes more intelligent
From above description, vehicle DVR recorder has seemed to be relatively complete. However, only ongoing innovation could make the market of vehicle DVR recorder develop fastly. From the introduction, author has known that currently some manufacturers has considered intelligent processing to some features of vehicle DVR recorder, for example, adding face recognition, counting of people amount, feature recognition and other functions and increase the practicability and pertinence of vehicle video recorder system and make storage become more intelligent.
After illegal event occured, police could only watch perpetrator's looking and wearing carefully through the video and till perpetrator appeared again, they could arrest the perpetrator according to their judgements. This approach is very time wasting and inflexible. Moreover, the staff in management center would unavoidly miss the situations of some events when watching the videos playback or the real-time videos. Therefore, implanting "nervous system" for vehicle video recorder and letting it analyze, judge as human brain will be the developement direction of vehicle video recorder in the future.
Regarding the merits of adding intelligent analyzation technology of car DVR, the cradle head of the car DVR will swift analyze the vast amount of data in video pictures, filter out the information that users do not care about and only provide useful key information to the monitors, which can effectively save bandwidth and greatly enhance the available network bandwidth.
More importantly, by analyzing the real-time or recorded video stream, intelligent video technology can detect suspicious activities, events and patterns of behavior and can make video monitoring converted from searching for suspects after events to be an assistant device to prevent the occurence of crime at the time when it's happening.
Intelligentization will play more and more important role in the storage application of car DVR in future. Car DVR manufacturers will research and develop more innovative technologies to assure the integrity and availability of the video recorded data according to requirements of users.
