Design Of Infrared Imaging System Based On Uncooled Detector

As the field of application of infrared imaging technology expands,single-band infrared imaging systems can no longer meet the growing demand for target detection capabilities.How to improve the quality of infrared images based on the hardware and software technology of existing infrared imaging systems has become a focus of research.Currently,infrared image fusion is an effective method to improve the quality of infrared images and has become a new trend in the development of infrared imaging technology.The fused infrared images enhance the understanding of targets and scenes and improve the accuracy of target detection.This paper focused on the construction of a long-wave uncooled infrared imaging system and completed a fundamental study of image alignment fusion based on current trends.The design of the long-wave uncooled infrared imaging system is divided into the overall structure design and the electronics unit design.The design of the overall structure primarily completed the parameter-selection of the front-end optical system and the selection of the uncooled infrared detector.The electronics unit design mainly completes the design of the detector drive circuit and data acquisition circuit,the main research work is as follows.(1)The selection of parameters of the front-end optical system of the imaging system is completed,and the optical module is designed to realize the functions of synchronous field of view and synchronous focusing of the system,and the superiority of the optical system is verified by simulation software.(2)Through the analysis of the detector products of major manufacturers at home and abroad,and considering the sensitivity,effective image rate and cost performance of the detector,the selection of the uncooled infrared detector was finally completed.(3)Complete the design of the driver circuit of the detector,the timing control circuit of the imaging system using the FPGA chip as the core,and the temperature control circuit of the imaging system using the temperature control chip.(4)Complete the design of the data acquisition circuit of the detector,use the FPGA chip to complete the imaging system signal processing and other functions.Complete the design of the analogue-to-digital conversion circuit using an analogue-to-digital conversion chip.Data transfer using PCI protocol.In the research process,based on the built long-wave uncooled infrared imaging system,the causes of noise generation in the imaging system are analyzed,and the suppression methods are proposed for the thermal noise and 1/f noise of the imaging system respectively.An experimental scheme for optimal voltage adjustment is proposed to enhance the image quality of the images taken by the imaging system.The infrared imaging experiments are completed based on the built imaging system,and a projection transformation model is used to complete an alignment algorithm for the fusion of infrared and micro-optical images when cameras at different locations in space capture co-planar points.The study shows that the matching resistor of the control circuit built by using a low temperature coefficient resistor in parallel with an adjustable resistor effectively suppress the thermal noise of the imaging system.A low temperature coefficient and high accuracy DAC,voltage follower and second-order low-pass filter circuit are used to complete the bias voltage design which can effectively suppress the 1/f noise of the imaging system.When the imaging system uses the voltage selected by the optimal voltage adjustment scheme for imaging,the dynamic range of the output image pixels can be maximised and high quality infrared images can be obtained.The infrared imaging experiments and fusion experiments have demonstrated the superiority of the imaging system and the ability of the built imaging system to perform image fusion well.