Abstract: With the rapid development of the social economy, people's living standards continue to improve, the number of various types of automobiles has increased significantly, and it is becoming more and more important to improve traffic efficiency. At present, countries all over the world have invested a lot of manpower and material resources to study the Intelligent Transportation System (ITS). As an important part of ITS, the electronic police system plays an important role in regulating driver behavior, eliminating traffic accidents, improving traffic enforcement and road traffic. Starting from the actual problems of the existing electronic police system, it has proposed its own solutions in system control, vehicle detection and system. The structure of the video detection system and control system based on embedded system is introduced.
0 Preface
With the development of China's economy, motor vehicles continue to grow, and the growth of existing roads and other hardware facilities has not been able to meet the growing traffic problems. Intelligent Transportation Systems (ITS) are gaining more and more attention.
The so-called Intelligent Transportation System (ITS) is a kind of comprehensive and comprehensive application of information technology, data communication transmission technology, electronic sensing technology and computer processing technology to the entire ground traffic management system. A comprehensive, real-time, accurate and efficient integrated transportation management system. In recent years, ITS has been widely used in urban traffic management, and has achieved good results in mitigating road traffic, preventing traffic violations and accidents. This paper proposes a vehicle violation video detection scheme for ITS applications, especially the application of electronic police system, to adapt to the development needs of ITS.
1 Electronic Police System
The electronic police is mainly for the automatic monitoring and recording of traffic violations that are easily caused by vicious accidents at the intersection of the motor vehicles. It has achieved unattended and uninterrupted monitoring, and the evidence is fully correct, improving the accuracy and efficiency of traffic enforcement. The traditional typical electronic police system is usually composed of system control, illegal vehicle detection, shooting, transmission and auxiliary equipment.
At present, the general electronic police system mainly adopts a loop coil inductor and an enhanced PC-based IPC platform control mode. The inconvenient installation and damage of the toroidal coil and the poor adaptability of the IPC to the outdoor environment have caused great difficulties for the normal operation and maintenance of the electronic police. Therefore, the vehicle violation detection technology has a great influence on the high-precision and large-area promotion of the electronic police. It is an important part of the electronic police system and an indispensable component of the traffic management system.
2 Existing vehicle violation detection technology
Vehicle detector is an indispensable part of the traffic management system. It mainly provides various traffic parameters to the information processing and information release unit in the monitoring system through data acquisition and equipment monitoring. It is analyzed, judged and issued as a monitoring center. Information and the main basis for proposing control schemes. Commonly used traffic vehicle detectors mainly include loop coil detectors, ultrasonic or microwave (radar wave) detectors, infrared detectors, video detectors, and the like.
Comparing several detection methods, it can be known that ultrasonic or microwave (radar wave) detectors and infrared detectors use harsh conditions and are used less, mainly for manual detection. At present, the most common and frequently used is the loop coil video detector, but the video vehicle detector has the following technical features compared with the detector such as the induction coil:
(1) The video detector is easy to install and maintain, and it does not need to excavate the road surface, and has little impact on road traffic.
(2) The video vehicle detector can detect a large traffic scene area, and a single camera can simultaneously monitor multiple lanes, thereby reducing the number of sensors installed and performing vehicle tracking in a wide range.
(3) It can provide most of the traffic parameter information, including traffic flow, bicycle speed, average speed, and vehicle spacing.
(4) The obtained video and image information is very intuitive, human-readable, and can be saved. This provides a reference for the monitoring personnel to perform related operations.
3 embedded video detection system
According to the requirements of traffic violation management and the main functions of the system, the traffic video detection system was studied and a feasible solution was formed. The idea is to install the video camera on the road pole and monitor the following road conditions. The captured digital video information is processed by the scene and transmitted to the traffic management center. At the same time, the electronic police video detection mode based on the embedded system is selected to improve the traditional electronic police system. The composition of the electronic police system is shown in Figure 1.
Figure 1 Electronic police system based on embedded system
It can be seen from Figure 1 that the electronic police based on the embedded system is mainly composed of three parts: video capture part, image processing and system control part, and network transmission part.
3.1 Video acquisition unit
The video signals obtained from the photoelectric conversion devices of the CCD camera are analog signals, and the analog television signals are converted into digital television signals through an analog/digital (A/D) conversion process. Analog-to-digital conversion involves three processes, namely sampling, quantization, and encoding. The purpose of the sampling is to convert the temporally continuous analog signal into a time-discrete signal, and the quantization is to convert the continuous sampling value in the amplitude into the discrete sampling value in the amplitude, and the encoding function is to discretize the sampling value. Compiled into binary numbers. The digital signal obtained by sampling, quantization, and encoding is a video PCM signal.
In the video processing, the analog signal is input from the camera. These full TV signals are extremely complicated, so the circuit for A/D conversion of the video signal is very complicated. Philips integrates these very complicated A/D conversion circuits into one piece. In the chip, the powerful video input processing chip SAA7113 is produced, which provides great convenience for the digital application of video signals.
SAA7113 is a video decoding chip that can input 4 analog video signals. It can convert 4 inputs through different configurations of internal registers, input 4 CVBS or 2 S video (Y/C) signals, and output 8 bits. "VPO" data bus. By setting the value of the register, the standard ITU-R BT656, YUV 4:2:2 format can be output.
The SAA7113 features dual-channel analog pre-processing circuitry including signal source selection, two analog anti-aliasing filters and analog-to-digital converters, an auto-clamp and gain control circuit, a clock generation circuit (CGC), and a digital multi-standard The decoder, a brightness/contrast/saturation control circuit and a color space conversion matrix. Mainly used in multimedia, video telephony, image processing and security.
Floating Ball Level Controller
The floating ball liquid level controller is composed of floating ball, plug rod, etc. It is installed on the top of the container through the connecting flange, and the floating ball floats on the liquid level according to the principle of equal volume of liquid. When the liquid level of the container changes, the floating ball also moves up and down. Due to the magnetic effect, the dry spring of the floating ball liquid level controller is magnetically attracted to change the liquid level position into an electrical signal, and the actual position of the liquid is digitally displayed through the display instrument, Floating ball liquid level controller to achieve remote detection and control of liquid level.
The floating ball liquid level controller is designed according to Archimedes' buoyancy principle. When the liquid level of the container changes, the floating ball also moves up and down. Due to the magnetic effect, the dry reed of the floating ball liquid level controller is magnetically attracted, so that the resistance in the sensor changes linearly, and then the converter converts the change of the resistance value into 4mA ~ 20mA standard DC signal output, Realize the remote detection and control of liquid level.
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Taizhou Jiabo Instrument Technology Co., Ltd. , https://www.taizhoujiabo.com