According to reports, more than 110000 people die in car accidents in China every year. Most of the accidents are caused by human factors, and fatigue and distraction are the main causes. With the progress of industry, the problems of driving safety and vehicle anti-theft have been put in front of people all over the world. Although drowsiness detection, brain wave and other related research are devoted to reminding drivers, the effect is not very satisfactory; In addition, the response time and cost of the system cannot be fully popularized.
In addition to worrying about driving safety, the anti-theft device of the vehicle itself is also annoying. According to the data , more than 72000 cars are stolen in China every year, with an average of one car stolen every seven minutes. Even if the current vehicles are equipped with anti-theft locks when leaving the factory and the users themselves will install anti-theft devices, the effect is not significant. At present, the monitoring system can send text messages to the users’ mobile phones as reminders at most, However, it is impossible to continuously transmit the real-time monitoring images, which is easy to produce false positives. If it is triggered by the vibration of a large truck passing by your car, the user must also hurry back to the vicinity of the vehicle, which is a waste of time and human resources.
In recent years, high-efficiency image processing technology with CCD camera is booming. The main reasons are the flexibility of software writing, the flexibility of CCD camera erection, the diversity of data captured by CCD camera and the low cost. In terms of vehicle safety auxiliary equipment, ultrasonic radar was widely used in vehicle safety protection in the past. However, the effective distance is limited, so the driver can only give reference to the distance information when reversing. There are also image applications, but at present, they are only limited to the function of image monitoring, such as reverse image display.
We believe that the image processing system can provide higher intelligence, which is enough to assist ordinary users in safety protection during vehicle driving. In addition, we also hope to provide the police or rental vehicle manufacturers with the information recorded in real time in the vehicle to effectively restore the accident scene and clarify the responsibility of the accident. Even, we hope that after the vehicle is parked, users can use their mobile phones to monitor the situation in the vehicle anytime and anywhere, so as to provide users with a more reassuring image anti-theft system.
Therefore, we have developed a system – Cadas (CSSP. Advanced driver safety assist system), which uses image technology to detect the road information in front of the vehicle, estimate the current position of the vehicle on the driving lane, and judge whether the vehicle is in a dangerous state; Further, we set up another camera behind the vehicle to send the obtained image information into the same system, and use the same algorithm to process the relative positions of the front and rear vehicles together by using the detected lane line information, so as to improve the stability of the system hazard warning.
In terms of vehicle travel image recorders, the vehicle travel recorders on the market are designed in a way similar to the black box of aircraft. In case of an accident, you have to wait for the decoding of the recorded data in the black box to have a chance to sort it out. Moreover, because there is too little recorded information, it is often impossible to correctly restore the scene of the accident. Cadas hopes to use H.264 real-time compression technology to accurately record the accident situation and provide it to the police as an aid.
We also have an idea to closely combine the traditional vehicle monitoring system with the embedded system with mobile network function, and be a pioneer in the vehicle electronics industry. This step will be a surprising leap forward in the field of vehicle monitoring, because all similar systems on the market do not have the function of transmitting images. We have improved and evolved the huge wired network monitoring host and transplanted it to the thin and short wireless network embedded board. In addition to the basic positioning tracking and anti-theft warning functions, image support is also added. In addition to the way of image transmission through IEEE 802.11x wireless network, it is more important to use 3G / wireless transmission to protect the user’s car regardless of time and space.
As shown in Figure 1, Cadas is composed of two TI DSP experimental boards. One is ti DM642, which is responsible for real-time and rapid calculation of front and rear lane lines and vehicle detection algorithm, and wirelessly transmits the detection results to another experimental board through ZigBee for warning. The other experimental board adopts Ti OMAP 5912. The biggest feature of this experimental board is to combine arm and DSP on an IC, so that we can use the powerful control function of arm and OS to drive all peripheral devices to meet our needs. On OMAP 5912, we successfully implanted embedded Linux, and through the corresponding driver, USB camera, wireless LAN module, touch panel, GPRS module, GPS module and ZigBee can work successfully and cooperate with each other under the control of OS to meet the requirements we expect.
System function and innovation
Cadas combines these peripherals and successfully realizes the following innovative functions:
Unique front and rear lane lines and vehicle detection
We will implement the algorithm specially designed for DSP on DM642. By programming and optimizing the memory and EDMA management of the hardware platform, this complex algorithm can achieve the efficiency of 30fps on a single DSP, capture the images of the front and rear sides in real time, judge whether the vehicle deviates from the lane and is too close to other vehicles, and then give a warning. In the part of lane line detection, we can successfully detect the lane line and vehicle information under various road conditions, including sunny, cloudy, rainy and night, which is a major breakthrough in stability and reliability.
Wireless ZigBee transmission signal
The main application object of Cadas is the vehicle. Because the space in the vehicle is limited, in order to make effective use of the space, we separate the two experimental boards. The signal communication part adopts the latest ZigBee wireless transmission technology. ZigBee design is originally suitable for transmitting control signals. Its transmission path is tested to be about 50m, which is very suitable for vehicles. Through ZigBee, We can place the experimental board in different positions, but still maintain the communication pipeline, which is very flexible in installation.
In case of bad driving conditions, it will be reported automatically in real time
The first cause of the accident is human negligence, and most of the human negligence occurs because the driver is physically and mentally tired. Before the accident, there are usually signs that the driver may deviate from the lane left and right first, or be too close to other vehicles. Most of the general warning systems only make a warning sound on the vehicle. In fact, such protection is insufficient. Because Cadas has GPRS module, it can automatically notify the police station and the unit of the vehicle in real time when the driving condition is bad. Prior to the occurrence of an accident, a one-step notice shall be given and a reminder shall be given by someone other than the vehicle, which can effectively reduce the accident rate.
Full H.264 driving record
If an accident still happens unfortunately, the most important part is to clarify the cause of the accident. At present, the vehicle recorder is not common. Even if there is, the recorded information is not enough. Only the throttle, brake and other data can not restore the accident scene in detail. Cadas can record the driving behavior in the whole process by using the H.264 animation compression technology realized on DSP, which can be provided to the police and relevant units for reference.
Mobile wireless vehicle anti-theft
Cadas can complement the weakest link of the current vehicle monitoring system – action monitoring. The current vehicle security system is not friendly to users and can not provide image information. The general car anti-theft system has no way to transmit the image to the owner. We break through this bottleneck and use 3G / GPRS to achieve real-time image transmission. So that the system platform can transmit the image status inside and outside the car to the mobile phone in real time, and the user can really master the car at all times.
We hope that through these advanced functions, people can have a safer and more assured environment. Cadas can not only be applied to the Lane Department warning system, but also be applied to the monitoring of cash carriers and the protection of mass transport vehicles, so that people walking on the road or sitting in the car can have a safer and more assured environment, and can also avoid sad accidents.
Specific research results and discussion
Because Cadas is powerful and contains many different fields, we roughly divide it into four items: lane line and vehicle detection algorithm; Report the abnormal driving conditions in real time; H. 264 animation compression technology and mobile wireless vehicle anti-theft system, and make a detailed analysis and comparison.
Lane line and vehicle detection algorithm
Our system can accurately detect vehicles of any color, and can avoid the noise such as national pier joints on the road. It can also operate in the tunnel. In addition, due to the changeable weather in the open air, after our test, we can accurately judge the lane line and vehicles whether it is sunny, cloudy, rainy or night. The test sections in Figure 2 (a) and (b) are the East-West Expressway in Hsinchu City, Taiwan. The climate is cloudy and rainy, so there are traces of wipers, but we still accurately detect them. Through our optimized algorithm, we can meet the needs of 30fps real-time operation and better protect the safety of users.
From table 1, we can see that this research occupies a place in the research of lane line detection, and has superior functionality and technology.
Report abnormal driving conditions in real time
When DM642 finds abnormal driving conditions, if the lane is offset or too close to the vehicle, it will wirelessly transmit the signal to OMAP 5912 through ZigBee, and OMAP will count first after receiving the signal. If the number of abnormal driving conditions is very large, it will send a warning message to the police station or other relevant units. After the remote user receives the warning message, You can immediately use the mobile phone to obtain the real-time situation in the car, so as to clarify whether the driver is in bad condition, and then make further reminder and protection. Figure 3 is a schematic diagram of real-time notification.
H. 264 animation compression technology
The H.264 animation compression technology implemented on Ti OMAP DSP still has high quality after reducing the complexity of the algorithm and optimizing the memory and calculus process according to the characteristics of DSP. Table 2 is a comparison table between this study and other studies. It can be seen from table 2 that the PSNR of different test images in this study is significantly higher and the display quality is indeed better.
Mobile wireless vehicle anti-theft system
Cadas is installed on the vehicle and transmits the real-time image information to the user’s mobile communication device through 3G / GPRS wireless network. The user can understand the current situation and make correct judgment. In addition to the active notification, Cadas also provides the function of passive detection. When the user is not in the vehicle, it can send a text message to the system on the vehicle. The system will take photos and return the GPS status immediately after receiving the text message. Even if the user is not in the vehicle, it can immediately understand the use situation and current location of the vehicle, which is important for fleet management, Very efficient. At present, limited by the speed of 3G, the frame rate displayed on the mobile phone is about 3fps. The results we have achieved on the mobile phone are shown in Figure 4.
Key points of award
Cadas has successfully realized many innovative and highly technical functions, such as real-time lane line and vehicle detection system at the front and rear sides; If the driver is abnormal, it will be reported automatically in real time; H. 264 driving record; Mobile vehicle anti-theft.
Cadas has successfully combined the driving safety auxiliary warning system, driving condition recording system and mobile video automobile anti-theft system. The technology of driving safety auxiliary warning system and mobile video automobile anti-theft system has been transferred to relevant automobile electronics manufacturers and has been highly praised. In addition to being recognized by the industry, the driving condition recording system and mobile video car anti-theft system have also applied for patents , which are further breakthroughs in technology. It can be seen that Cadas is not pieced together for competition overnight, and there is no doubt in terms of technical maturity and system integrity. We hope to closely combine the convenience brought by the advanced electronic industry with automobile manufacturers, so as to make today’s society with more and more cars safer, less accidents, and easier to protect vehicles from theft. It is the goal and mission of our electronic industry talents to devote the new generation of technology to the happiness of the next generation of mankind.
Responsible editor: GT