Research On The Key Technology Of Online Monitoring Infrared Thermal Imaging System

Public security has become an import society problem in today’s world. Most of these public safety accidents happen at night in the place where no people on duty and easily for the Pedestrian to break into. The Traditional visible light Online monitoring equipment can’t meet the needs of the field of security. Compared with the visible light imaging system, it has a great advantage. The infrared thermal imaging system is the object of the temperature information and can’t be affected by the bad weather. Based on these reasons, i designed the On-line monitoring infrared thermal imaging system.The thesis aims to design the On-line monitoring infrared thermal imaging system as the target. The modular design method is adopted under the premise of analyzing the system requirement. First, the system is divided into infrared thermal imaging and on-line monitoring two modules according to the function. The infrared thermal imaging modular is mainly used to collect the thermal radiation and the signal process with correcting、stretching、filtering and coding of BT.656. The On-line monitoring modular is mainly used to pedestrian detection、transmit the image data and peripheral interface extension(mainly the SD card interface, the wifi modular interface, the USB 2.0 interface, the audio interface, the RS232 serial interface). In the overall design of the system, the paper mainly from the infrared thermal imaging module of the power supply scheme, the low noise drive of sensor, the design of BT656 coding, Pedestrian detection in infrared image, the On line monitoring data transmission and control to introduce the system.The low noise design of infrared thermal imaging module of the power supply scheme, sensor drive can effectively reduce the noise coupled to the system and improve the image quality. The design of the power supply scheme is based on the requirements, choose the proper power chip to build the power structure and clarify the matters of power supply scheme. The design of sensor’s driver mainly focuses on the Analog bias voltages and the digital signals, the design and implementation of Analog bias voltages is mainly based on the High precision DAC and High PSRR op amp, for digital signals which strict constraints on the timing to reduce delay. The coding of BT656 mainly considers the hardware cost and speed requirement. Taking into account the characteristics of people in the infrared image, a pedestrian detection algorithm based on HOGfeatures and LIOPfeatures is used in the neural network. Based on the RTSP protocol group to transmit real time data stream and ONVIF protocol to control the network parameter, the video standard, image quality, therate of code and so on.Final, debug and verify the system, the results show that the system has achieved practical needs. This paper expands the scope of application of infrared thermal imagingtechnology. It also provides the basis for the further design and optimization of on-line monitoring infrared thermal imaging system in the future.