Research On The Ultra Small Uncooled Infrared Thermal Imaging System

With the progress of science and technology,a variety of sensors continue to appear.The sensor can sense the information into electrical signals.The system processes into the information that human beings could observe,control and analyze,help human beings continue to expand the field of perception.Infrared detector is such a special sensor and the infrared thermal imaging system processes the IR detector output signal to facilitate human observation,analysis and application.Because infrared thermal imaging system has the unique advantage compared with visible light,there are demands for using infrared thermal imaging system in various sectors and countries around the world invest heavily in the research.Based on the trends that infrared thermal imaging system develops toward miniaturization,low power,low cost,high resolution,this paper will design and achieve ultra-small and low-power infrared thermal imaging system.In this paper,in the view of the requirements of ultra-small and low power consumption,the digital processing module,display and motor module,analog bias scheme and detector output signal processing scheme are compared and researched.Through the above measures,the signal processing solution of 640×512 uncooled thermal imaging systems are formed.Through the analysis of power demand,the distributed power supply scheme is selected for the system.The infrared thermal imaging system is a mixed-signal system,and involves high-speed DDR signal,so the article put forward the guidance requirements in the layout of the system,PCB stack design,signal integrity and power integrity.The volume of the system decreases and the power consumption is further reduced through the measures above.The original infrared images have fixed noise,low SNR and fuzzy details resulting from the process defects and material properties.Therefore,in the thermal imaging system,a series of image processing is needed to improve the image quality.Under the requirement of real-time system,the non-uniformity correction,image de-noising and image enhancement processes are operated.On the basis of the general two-point correction,this article proposes an improved two-point correction method and has verified.As for the low signal to noise ratio(SNR)and low contrast of the image,the median filter and histogram equalization are used to process the infrared image.The image quality has been significantly improved by using the median filter and histogram equalization method.The system is debugged and verified and the results are recorded.After measurement,the size of the thermal imaging system is 35*35*21mm,the weight is 76 g.The input power supply range is 4~12V,the power consumption is 1.7W.The NETD of system is 64 mK.By loading the image processing program and comparing the output image,we can see that the real-time performance of the system is satisfied and the image quality is improved.The system has achieved the design target and has laid a good foundation for the following system design and development.