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Abstract: In order to meet the needs of distributed single-camera remote transmission and accelerate the modernization of digital network in today, an innovative implementation of FIC8120 (ARM-SoC) and PoE-based digital real-time IP-Camera is proposed. The system components and hardware and software design. The system has many advantages such as real-time video recording, motion detection, power over Ethernet, low power consumption and low cost, and is suitable for the next generation video surveillance requirements, and has a good application prospect.Keywords: network camera; Power over Ethernet; video surveillance
introduction
In today's era of digital Internet, any electronic device is striving to develop in the direction of digitization and networking. The network is drawing closer to us, and the internet is changing our lives. The monitoring field has not hesitated to develop rapidly towards the network, and the network development of the camera is also unstoppable. [6] IP cameras will enable remote video surveillance, which will change the dilemma that the original distributed analog cameras could not achieve low-cost long-distance transmission!
In order to meet the needs of distributed single-camera remote transmission, modern IP cameras must have features such as small bandwidth, high image quality, low cost, and low power consumption. The system uses digital CMOS digital image sensor, MPEG-4 high compression ratio VGA/CIF ARM-SoC and Si3401 Power over Ethernet and Ethernet device controllers to propose an all-digital real-time network camera solution to meet current and future Monitor demand.
Overall hardware architecture
The whole system consists of CMOS video acquisition, compression coding, video processing, Ethernet power supply and Ethernet data communication. From the front end to the back end, several processes such as "Lens OV7660 → FIC8120-SoC → PoE/Network" are sequentially passed.
According to the different needs of users, we can select the corresponding lens group, the analog information obtained from the lens is digitally collected by OV7660, and then transmitted to the subsequent processing components by this CMOS sensor.
1. FIC8120-SoC related design
The FIC8120 is a highly integrated, SoC with MPEG4/JPEG video image acceleration, low cost, low power, ARM922 core designed by FERADAY, a well-known UMC company. [1]
As the CPU of the system, the FIC8120 captures the ITU 656 YUV 4:2:2 VGA format digital image signal output by the OV7660 [5] and DMAs it to the external SDRAM through the AHB bus. At the same time, it is transmitted to the internal MPEG-4 Codec for encoding. After the encoding is completed, it is sent to the Ethernet MAC for output from the network port after the relevant processing selected by the user.
This design supports the industry's commonly used VGA (640 × 480) @30fps and CIF (352 × 240) @ 30fps resolution and frame rate for compression encoding, real-time recording, and has efficient motion detection technology. Motion detection technology is used to trigger recording only when motion pictures are captured, thereby greatly reducing unnecessary disk space. The Codec also supports hardware DCT/IDCT, quantization/inverse quantization, variable length coding and other advanced technologies, which significantly improves coding efficiency and significantly reduces power consumption. The system also makes full use of the FIC8120's built-in 100K gate MPCA (similar to FPGA) to implement practical OSD (character overlay) and other functions.
In addition, the FIC8120 has a wealth of peripherals and IO, which also provides great convenience for future system upgrades. The audio compression port (I2S/AC'97) and CCIR601/YCbCr/RGB video input are mainly reserved here.
2. Si3401 PoE power supply design
For low power consumption and ease of use, and verified by the supply voltage and power, the system uses Silicon Labs' Si3401 Power over Ethernet chip. [3]
Power over Ethernet (PoE) is the IEEE 802.3af standard for transmitting power over Ethernet cables. 802.3af supports two power supply modes, namely, vacant line power supply and signal line pair power supply. In order not to change the off-the-shelf network equipment and adapt to future network equipment, the system uses the vacant line pair power supply mode. [4]
Ethernet connects the signal line to the physical layer (PHY) through the network transformer to the FIC8120, and the other vacant pair connects to the Si3401 for power supply adjustment. Since the IP-Camera is a stand-alone powered device, the design configures the Si3401 in a non-isolated DC-DC regulation mode and outputs a 5 VDC initial supply.
Due to the voltage requirements of the CMOS image sensor, CPU, and peripherals, this design uses the LM1117 to step down the 5V to 3.3V-1A. Considering that the FIC8120 requires a low noise and high precision 1.8V core voltage, I have adopted the TPS71229 ultra-low noise 250mA dual-channel LDO, which not only provides reliable and stable 1.8V-250mA, but also provides CMOS image sensor through peripheral circuit configuration. 2.5V required.
System software design
In view of the ARM922 architecture of the FIC8120, the system ported the FIC8120 to the low-cost Embedded Linux 2.4.19 and tailored and optimized it according to the FIC8120 and IP-Camera. The system uses the standard GNU toolchain.
Based on the FIC8120, we first packaged a board support package (BSP), including CPU initialization, memory management, various peripheral drivers (Ethernet, etc.), Linux Kernel initialization, interrupt handling, clock management, watchdog, I/ O system and file system, etc. BSP is also similar to the initialization and hardware abstraction layer. The upper application is related to the API provided by BSP. The system initialization program also completes the system's network allocation, video-related parameter configuration (including video resolution, code stream, frame rate, rate/variable rate, etc.), and turns off unused peripherals to minimize power consumption. .
In addition to the BSP, the software system also includes IP-Camera's key TCP/IP and UDP protocol libraries. The network protocol provided by FARADAY is quite complete and highly time-sensitive. [2]
Application software includes file system management, network services, mail delivery, file transfer, and detection of alarms. The network service program finishes sending the video to a port on the network for access by other network devices (such as a remote client); the mail sending and file transfer program detects the moving target and needs an alarm when the time is The image is intercepted and transmitted to the mail server or file server; the detection alarm program determines whether the target moving in the video needs an alarm according to the rules set by the remote host.
The application also includes a Web Server, with a dedicated Media Player program, the application software can process external service requests according to the HTTP protocol, send MPEG4 code stream to Ethernet, handle external control commands, motion detection alarms, and so on. After connecting to the FIC8120 through IE browser, you can make related settings for the FIC8120 on the page, such as network configuration, multi-stream monitoring, SMTP service, FTP server, video quality, motion detection, administrator password management, etc.
Conclusion
This IP-Camera uses the LAN to remotely access the Web Server in the VGA resolution, maximum code stream 2Mbps, frame rate 30fps, variable rate, motion detection configuration, and performs preview, video recording, playback, setting, etc. The average storage space of the video is controlled within 500MB/Hour; the overall power consumption of the system is 3-7W, and the power efficiency is >80%. The system is extremely suitable for large and medium-sized monitoring sites. It can be arranged with only one network cable and a small number of Switch/Hubs. It can also be recommended for applications such as original equipment modification and expansion. There is no doubt that this IP-Camera system is one of today's and next-generation digital and networked monitoring optimizations.
references
[1] FARADAY. FIC8120 MPEG4 Codec Platform SoC Datasheet. March, 2006
[2] FARADAY. Faraday Linux Software Development Kit for FIC8120. October, 2005
[3] SILICON LABS. Si3400/Si3401 Datasheet. December, 2006
[4] SILICON LABS. Using the Si3400 and Si3401 PoE PD Controllers in Isolated and Non-Isolated Designs. AN296. December, 2006
[5] OmniVision. OV7660/OV7661 Datasheet. 2004
[6] Hou Junhua, Hu Jinyan, Su Boshi, Chen Feng. A new embedded MPEG-4 DVR system design. Microcomputer Information. 2006, Vol.22-No.14, P187-189
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