Abstract: An electronic traffic police system based on embedded Web. This system uses a digital camera as the main image capture device and utilizes an ARMS3C4510B microprocessor for remote image transmission via Ethernet. Keywords: Embedded Web, Electronic Traffic Police System, Microprocessor. In recent years, intelligent transportation systems have developed rapidly, striving to effectively integrate advanced information technology, communication technology, computer technology, electronic control technology, and other high-tech applications into the entire transportation management system, establishing a comprehensive, real-time, accurate, and advanced transportation management system on a large scale. To date, countries and regions such as Japan, the United States, Western Europe, and Australia have established corresponding institutions to engage in related development and application research, and have achieved some results. Running red lights is one of the main causes of traffic accidents. The main function of this electronic traffic police system is to capture and process vehicles running red lights, which is an important component of modern urban traffic monitoring systems. Currently, because information related to vehicles running red lights is not yet connected to the network in real time, there is a significant lag in the acceptance, fines, and completion of post-traffic management for violating vehicles. Therefore, this system adopts an embedded Web-based solution to ensure the system's real-time performance, and the use of a high-precision digital camera compensates for the insufficient clarity of CCD cameras. Good application results have been achieved. 1. Design Scheme 1.1 Hardware Part ARM (Advanced RISC Machines) is a world-renowned company in the microprocessor industry, designing a large number of high-performance, low-power, and inexpensive RISC processors and related software. From the perspectives of cost-effectiveness and practicality, this system uses the Samsung S3C4510B embedded processor based on the ARM7 core, along with a development board system built with memory chips, a main USB interface, an Ethernet chip, serial and parallel ports, as the hardware development platform for the entire system. Different parameters are set in the interface logic circuit according to actual needs, and appropriate base addresses and interrupt numbers are set to avoid conflicts. Pin assignments are also performed according to the development board's manual. 1.2 Embedded System Software Structure This system uses the μCLinux operating system. Currently, the publicly available embedded operating systems are μC/OS and μCLinux, each with its own characteristics. μC/OS has a small footprint and excellent real-time performance. Although μCLinux has a relatively large footprint and average real-time performance, it supports multiple file systems, embeds the TCP/IP protocol, and can draw on the rich resources of Linux, making it suitable for more complex systems. Given that this system needs to be Ethernet-oriented and is relatively complex, μCLinux was chosen as the operating system. μCLinux is a variant of Linux, the main difference being the memory management mechanism and process scheduling management mechanism of the two. At the same time, in order to adapt to the needs of embedded applications, μCLinux adopts the romfs file system and simplifies the glibc C language library on Linux. The software design of this system includes: platform porting of the μCLinux operating system, trimming of the embedded operating system μCLinux, hardware drivers, application programs, human-machine interface, etc. (1) Port μCLinux on the ARM platform and establish the μCLinux development environment on the PC. The ARM development board is used to run the operating system and application software, while the PC completes the kernel compilation of the operating system used by the target board and the development and debugging of the application programs. The two are generally connected through serial port, parallel port or Ethernet interface. (2) Trim the system kernel to minimize its resource consumption while ensuring functionality. (3) Hardware drivers include USB driver, USB controller driver, Ethernet controller driver, etc. (4) The application program is mainly responsible for transmitting the data uploaded by USB and serial port to Ethernet. (5) The human-machine interface includes a local interface and a remote interface. The remote interface is mainly stored in the dynamic webpages of the embedded server for management and query. 2 System Composition This system consists of a front-end vehicle photography control subsystem, an information transmission subsystem, and an information query management subsystem. The composition structure is shown in Figure 3. 2.1 Vehicle Photography Control Subsystem The front-end vehicle photography control system consists of an embedded system, a microcomputer chip ground loop detection device, a high-precision digital camera, and related communication and transmission accessories. The moment a vehicle violates a traffic rule and hears a red light, the microcomputer chip sends a timely and accurate traffic violation signal based on the signal change of the ground loop detection device. After receiving the detection signal (running a red light, driving against traffic, etc.), the front-end embedded control host controls the shutter of the digital camera and judges the ambient light level at any time to decide whether to turn on the flash. The digital camera takes a picture after receiving the flash and the photo signal. The captured information is first stored in the camera's 8M card (Smart Media Card). 2.2 Information Transmission Subsystem Information is transmitted through the network. Currently, there are roughly three methods for embedded systems to access Intcnlet: one is through a dedicated web server; the second is through a dedicated embedded gateway; and the third is to extend standard network technology (TCP/IP) to embedded devices, with the embedded system itself implementing web server functionality. This paper adopts the third method, which only requires writing dynamic web pages to conveniently manage and query relevant information through a web browser. The information transmission subsystem consists of two parts: one is the transmission process of photos and other related information from the digital camera's USB port to the Ethernet controller; the other is the transmission process of information from the Ethernet controller to the Ethernet. 2.2.1 Information Transmission from Digital Camera to Ethernet Controller After the intersection green light turns on, the photo processing task in the embedded system checks whether there is a photo stored in the camera. If so, the photo is transferred to the Ethernet controller through the digital camera's USB interface, ensuring that the digital camera always has enough space to take pictures of violations. At the same time, the time, location, and scene data of the violation are saved in the photo for later processing. The digital camera and the Ethernet controller transmit information through the main USB port. The main USB chip used in this system is the Cypress SL811HS. This chip is specifically developed for embedded systems, is inexpensive, and conforms to the USB 1.1 specification. 2.2.2 Information Transmission from Ethernet Controller to Ethernet The Ethernet controller is connected to the Ethernet network to transmit captured violation photos in real time, ultimately achieving real-time transmission of violation photos and related information. 2.3 Information Management and Query Subsystem Based on B/S Architecture Vehicle violation photos are the basis for traffic management departments to process drivers who violate traffic rules; therefore, the photos transmitted from the front end also need to be managed. The monitoring center establishes a computer local area network system, setting up multiple workstations to perform tasks such as data entry, review, acceptance, delivery, notification, file blocking, re-examination notification, fines, file unblocking, and completion of processing. This system needs to interconnect with basic databases such as motor vehicles and drivers for strict searching, comparison, transfer, and file blocking, and also needs to interconnect with multiple external systems for traffic violation notification and tracking of fine execution. The external systems involved mainly include post office delivery systems, bank payment systems, motor vehicle and driver query databases, and traffic violation databases. 3 Key Design Issues 3.1 Implementing Ethernet Access Based on Embedded Web This system uses an S3C4510B embedded processor and an Ethernet interface chip RTL8201BL to form an Ethernet measurement and control gateway. The RTL8201BL is connected to the S3C4510B processor via a bus, and interrupts are handled by the S3C4510B's external interrupt. The network layer mainly performs the conversion between Ethernet TCP/IP protocol and fieldbus RS-232 protocol, completing the interconnection between Ethernet and fieldbus networks and realizing data exchange between different Ethernet and fieldbus networks. Data flow: Request information comes from Ethernet, passes through the RJ45 interface to the RTL820BL, the IP packet is sent to the S3C4510B, unpacked, the data is extracted, and then reassembled into frames according to fieldbus communication protocols such as RS-232; or the data frame sent by the front-end imaging system is reassembled into IP packets and sent to Ethernet. The key to network transmission is developing a TCP/IP protocol stack responsible for data transmission and remote command processing. First, the type of network protocol is selected. Since the amount of data to be transmitted for photos is small, but the reliability requirement is high, the reliable data transmission control protocol TCP is selected at the transport layer, and the basic data transmission protocol IP is selected at the network layer. 3.2 Writing Hardware Drivers in the Embedded System μClinux Hardware drivers include USB drivers, USB controller drivers, Ethernet controller drivers, etc. In Linux, drivers can be compiled in two ways: statically compiled into the kernel, or compiled into modules for dynamic loading. Since μClinux does not support dynamic loading of modules, the method of statically compiling device drivers into the μClinux kernel is chosen here. When the Linux kernel starts, it calls the device driver's initialization function to initialize the device. A major device number and a slave device number need to be assigned to the device, which cannot be duplicated with existing device numbers, and then a new device file is created. The device driver file is added to the corresponding directory, and the corresponding Config.ini and Makefile files are modified. The corresponding device driver is loaded during kernel compilation, and the generated μClinux binary file is burned into flash memory. Then, various external devices can be used. The interrupt handling in the driver adopts a top-half and bottom-half processing method. The top-half completes interrupt registration, interrupt cause marking, scheduling the bottom-half, and then exits. The lower half performs data processing when it is relatively safe, allowing the upper half to continue providing services to other systems while the lower half is in operation. This electronic traffic police system utilizes high-tech methods such as embedded web and digital communication to transmit information on violating vehicles to the Ethernet in real time. The monitoring center can easily manage the information, and users can query it at any time via a web browser. With the rapid advancements in digital camera technology, shutter speeds of typical digital cameras can reach 1/1000s, supporting continuous shooting, fully meeting the requirements for high precision and three elements (likely referring to specific data elements). The use of embedded web enhances the system's real-time performance and reliability, significantly reducing delays in processes such as violation processing, payment, and database updates. It replaces PCs with microcontrollers and Ethernet interface chips for on-site control, requiring only a few network computers for monitoring, greatly reducing costs. Utilizing the abundant resources of digital cameras and Ethernet to build this control system is a real-time, low-cost, and highly reliable technical solution. The establishment of this system effectively improves the efficiency of recording and managing vehicles that run red lights, enhances traffic management, and has good economic benefits and broad application prospects.