1. Introduction
With the rapid advancement of communication and network technologies, remote monitoring of critical locations via the internet has gained significant attention. Network cameras have emerged as a key solution in this field, combining traditional camera technology with modern networking capabilities. These devices can transmit high-quality video signals across the globe through standard web browsers, eliminating the need for specialized software. To handle the large volume of data, video compression is essential, often using technologies like DSP and MPEG-4 algorithms. However, these approaches can be complex and costly. This paper introduces a network camera that utilizes a dedicated MPEG-4 compression chip and an embedded Linux system, offering cost-effective, efficient, and real-time performance with a wide range of applications.
2. System Overview
The overall system design includes both hardware and software components, which are closely integrated to ensure seamless operation. The hardware module consists of a microcontroller, while the software part involves the implementation of an embedded Linux system. The microcontroller, such as the AT91RM9200, serves as the core of the system, managing tasks like system initialization, control of peripheral devices, and data transmission. It also handles communication with other modules, including video compression chips, network interfaces, and camera control units. The system's architecture is designed for efficiency, scalability, and real-time performance.
3. Hardware Design
3.1 Microcontroller Module
The microcontroller, based on the ARM920T core, provides high processing speed and strong functionality at a low cost. It controls various peripherals through built-in interfaces like SPI, USART, and Ethernet, ensuring smooth interaction between different parts of the system. The microcontroller initializes and configures other components upon startup, enabling the system to function properly. Its role is crucial in managing system resources and coordinating operations across multiple modules.
3.2 Video Compression Module
This module uses the TVP5150 video acquisition chip and the MPG440 compression chip to process and encode video streams. The TVP5150 supports multiple video standards and outputs digital signals suitable for further processing. The MPG440 chip compresses the video data into an MPEG-4 format, supporting various resolutions and features like motion detection and dynamic quality adjustment. The compressed data is temporarily stored in SDRAM before being sent over the network.
3.3 Network Module
The network module facilitates data transmission over the internet using the AT91RM9200’s built-in Ethernet controller. It communicates with the DM9161E physical layer chip through the MII interface, allowing for reliable data transfer. The system manages data transmission through DMA channels, minimizing the load on the microcontroller and ensuring efficient network communication.
4. Software Design
4.1 Embedded Linux System
The embedded Linux system is responsible for managing the entire platform, from booting the kernel to handling user applications. It is stored in DataFlash and loaded into SDRAM during startup. The system supports different file systems, such as ROMFS for read-only data and JFFS2 for dynamic configuration files. Linux's open-source nature, flexibility, and cross-platform support make it an ideal choice for embedded applications.
4.2 MPEG-4 Encoding Module
The encoding module is responsible for initializing and configuring the video capture and compression chips. Once the system is ready, it processes video streams, compresses them into MPEG-4 format, and stores the data in memory. The encoded stream is then transmitted over the network, ensuring real-time video delivery.
4.3 CGI Program
CGI programs enable interaction between the web server and users, allowing remote control of the camera and configuration of settings. These programs run on the server side and respond to user input by modifying system parameters or triggering actions. They are implemented using a combination of C and shell scripts, providing flexibility and ease of integration with web pages.
4.4 MPEG-4 Decoding
MPEG-4 decoding is essential for receiving and displaying video streams on remote devices. The decoding process involves reconstructing video frames from the compressed data, ensuring smooth playback. The standard supports interactive multimedia applications, making it suitable for use in video conferencing, surveillance, and streaming services.
5. Conclusion
This paper presents a network camera system built around the AT91RM9200 microcontroller, TVP5150 video capture chip, MPG440 compression chip, and DM9161E network interface. After testing, the system demonstrates stability, reliability, and high image quality. It is well-suited for applications such as traffic monitoring, industrial surveillance, home security, and video conferencing, showcasing the potential of embedded systems in modern networking environments.
Automatic Light Curtain,Laser Light Curtain,Automation Light Beam Sensor,Automatic Infrared Beam Sensor,Infrared Beam Curttain Sensor,Infrared Beam Sensor
Jining Keli Photoelectronic Industrial Co.,Ltd , https://www.sdkelien.com