Simulation And Verification Of Snapshot Video Spectral Imaging System

Hyperspectral imaging is one of the research hotspots of modern optical remote sensing,and it is widely used in environmental monitoring,mineral exploration,agriculture and forestry protection,and national defense.Hyperspectral loads with high-resolution imaging capabilities generally use dispersive(such as gratings,prisms)spectroscopy systems,which limit the imaging to a linear field of view through a single slit,and use the spectroscopic part to complete the fine spectroscopy,a2-dimensional sensor is used to achieve simultaneous acquisition of 1-dimensional space and 1-dimensional spectral.This imaging system principle information acquisition model is simple,but the limitation of the line imaging field of view is difficult to achieve effective detection of dynamic scenes.For example,when the scene to be detected is a moving car or gas,this imaging system can hardly reflect the dynamic defects of the target.How to realize the hyperspectral imaging video observation of the dynamic scene is an international research hotspot.Coded aperture spectral imaging is one of the new types of hyperspectral technologies with snapshot video imaging capabilities.Based on the basic principle of compressed sensing target sparseness,upgrade the single slit to a two-dimensional aperture coding version with coding properties,the 2-dimensional sensor can realize the information of the3-dimensional scene(2-dimensional space+1-dimensional spectrum)through specific coding and reconstruction,at the same time,it acquires and uses algorithms to reconstruct the spectral data cube,which has the ability of video spectral imaging of dynamic target.The analysis from the mathematical principle is non-full sampling.When the spectrum information of the target to be detected has high frequency characteristics,it is easy to produce spectral distortion,and the coding and reconstruction algorithm is relatively complicated,which makes it difficult to realize real-time information solution.Target at the questions above,this thesis proposes a new spectral imaging method based on a uniform slit array,and conducts simulation analysis and experiments.The main work of the thesis is summarized as follows:1.Based on the analysis of the dispersive single-slit hyperspectral imaging method and the compressed sensing aperture coded video spectral imaging method,a coded spectral imaging system based on a uniformly distributed multi-slit array is proposed and implemented.The method uses a combined prism to realize the spectral spectroscopy of the opposite field of view,and use the uniform slit array encoding with micro-movement properties to realize the rapid collection of three-dimensional information of the field of view.The system can be implemented in engineering without using complex coding algorithms.It is theoretically analyzed that this method can solve the problems of high time resolution,high spatial resolution and high spectral resolution while taking into account the problems,and has the ability of video spectral imaging of dynamic targets.2.The new method proposed in this thesis,detailed simulation and comparison work has been carried out.The results show that the time collection efficiency of this method is increased by 17 times compared with the single-slit dispersion system,and the spectral data reconstruction results are not distorted,which is 1.8 times the structural similarity index and 1.17 times modified spectral angle mapper of the 50%sampling rate coded aperture system.This method increases the sampling speed on the basis of the full sampling of the single-slit spectral imaging system,continues the advantage of the snapshot of the coded aperture spectral imaging system,makes up for the problem of spectral information distortion,and the reconstruction algorithm is less complex than the coded aperture,with good engineering feasibility.3.Based on the proposed method,the design and implementation of the uniform slit array are completed.On this basis,a complete uniform slit array encoding spectral imaging system is built.After a specific design,the distance between adjacent slits and the detection wavelength which dispersion range was fully matched,high-performance visible light camera is used to sample spectral information in two-dimensional space without aliasing,and micro-displacement motor is used to control uniform slit array encoding plate for micro-scanning to achieve full field of view coverage,so as to achieve snapshot video spectral imaging.The purpose of this thesis is to realize the new method proposed in this thesis from the hardware.4.Using the built imaging system,the proposed method was experimentally verified,and the optical MTF,detection sensitivity,spectral resolution,and video imaging frame rate of the system were tested.Finally,the system was used to carry out imaging verification in the external scene,and the results showed that the system can better verify the new method proposed in this thesis,and it is initially feasible for engineering.5.At the end of the thesis,the application prospect of the method is analyzed and prospected,and a method is proposed to further improve the system performance index,which provides research ideas for the further engineering development of this method in the future.