Research On Key Technologies Of Real-Time Spectral Recognition For Interferometric Imaging Spectrometer Based On FPGA

The interferometric imaging spectrometer acquires two-dimensional interference images of the target region by an optical interference system,and obtains spectral data corresponding to each pixel in the images according to the principle of Fourier transform spectroscopy.By analyzing the spectral data,the target can be detected and identified,and it has important applications in the fields of atmospheric detection,environmental and disaster monitoring,and military reconnaissance.The current interferometric imaging spectrometer system generally acquires the target interferogram information in real time,and then compresses the information and sends it to the data processing platform for spectral recovery and spectral recognition.The whole process takes a long time and it cannot achieve the requirements of urgent business,such as military reconnaissance,real-time monitoring of major disasters,etc.Therefore,it is extremely urgent and necessary to conduct real-time spectral recognition research for interferometric imaging spectrometer.Interferometric imaging spectrometer real-time spectral recognition research faces the technical problems of high resolution of interferogram acquired by interferometric imaging spectrometer,large amount of information of restored spectrum and high real-time requirements of spectral recognition algorithm.The FPGA chip is flexible in design,suitable for data parallel and pipeline processing,large capacity,low power consumption,and is more suitable for real-time processing of data than other processors.In this paper,the key technologies of real-time spectral recognition based on FPGA for spatial modulation interferometric imaging spectrometer,such as interferogram data generation,spectral restoration,spectral recognition and target scene inversion,are studied for the above technical problems,and corresponding modules are designed according to each key technology.And the modules constitute an interferometric imaging spectrometer real-time spectral recognition system.In this paper,the interferogram data generation module is used to simulate the interferometer and the analog/digital converter to provide the interferogram data for the system.The spectral restoration module receives the interferogram data output by the interferogram data generating module,and performs operations such as DC,apodization,Fourier transform,and phase correction to complete the restoration of the spectrum and output the restored spectral signal.The spectral recognition module mainly uses multichannel spectral angle calculation,tree spectral type judgment and other schemes to perform multi-channel spectral recognition on the restored spectrum,and outputs spectral type labels.The target scene inversion module comprises a cache module,a pixel labeling module and a display module,which are used for buffering the spectral type label,labeling the corresponding pixel according to the spectral type label,and inverting the target scene in a video form on the display.The system is designed by Verilog HDL on the Vivado platform,and the real interferogram data is used to verify the hardware of the system.The verification results are completely in line with expectations,which proves the correctness and effectiveness of the system design.The system lays a solid technical foundation for the engineering realization and application of real-time spectral recognition of interferometric imaging spectrometer.