Development Of Network Camera Used In Underground Based On ARM9

With the development of mine informatization, the higher requirement toward mine safety monitoring has been proposed. In order to solve the disadvantages of poor signal quality, lack of short transmission distance about analog camera and mine monitoring equipment couldn't combine images, sounds and environmental parameters, a kind of network camera used in underground is designed in this thesis. The network camera is in conformity with the intrinsically safe demand and has the functions of video monitoring, audio monitoring, environmental parameters accessing, remote network transmission. Hence, it will play an important role on the monitoring of mine security production.Through analyzing the system requirements and comparing different solutions, the design plan which uses Freescale i.MX27 as main processor is established in this paper. i.MX27 is based on ARM9 architecture and integrated hardware video codec. On this basis, the modular approach is used to design the hardware circuits which include minimum system, video module, audio module, environmental parameters accessing module, ethernet module, power module. In order to achieve image acquisition under low-light environment, video module utilizes low-light CCD image sensor. The information collected by video module would be processed by H.264 hardware video codec inside the processor, and then can be transmitted to the monitoring center via Ethernet. Audio module has completed voice data processing by audio codec chip. Environment parameters accessing module could access environment parameters by RS-485 interface or wireless communication module with Mini PCI-E interface. The ethernet module is used to implement the remote transmission about information of video, audio, environmental parameters through ethernet in mine.The low-voltage(≤3.3V) design of system power not only conforms the intrinsically safe demands, but also realized the low power consumption(4.5W) of the device. The reliability of system is improved profoundly through the design of the six layer PCB board and EMC. In addition to complete system hardware design, Linux operating system migration and network device driver design are finished in this paper. They are closely related with the hardware.In the test of system, the system not only can meet the electrical performance requirements, but also can finish the image acquisition of the common environment and simulated Low-light environment, realized the data of video and audio compression and network transmission remotely. The experiment shows that the network camera used in underground based on ARM9 can realize the collection, processing, storing and transmitting of the video and audio data, which have the higher application value and research significance.