The Study On The Design Of Optical System Of The Spectral Imaging Technology Of Adaptive Classification Based On DMD

Imaging spectrometer is a kind of equipment which can obtain two-dimensional image information and one-dimensional spectral information at the same time.Rich data is convenient for target classification and recognition,and widely used in mineral exploration,remote sensing,marine monitoring,biomedical research and other fields.However,the three-dimensional data given by the imaging spectrometer is a high-dimensional and redundant data,which is not intuitive enough in use.It needs to rely on computer data processing to obtain classification and recognition results.With the complexity of imaging spectral instrument and the improvement of application requirements,the index of imaging spectral instrument increases,and a large amount of information brings great pressure to data transmission,storage and processing.In order to solve this problem,the adaptive classifying spectral imager is studied in the dissertation.The core idea of the technology is to eliminate the intermediate data transmission and storage process through the device's modulation of optical information combined with data processing algorithm,to directly obtain the classification results and simplify the processing flow.At the same time,the feature of "what you see is what you get" is more user-friendly.The paper focuses on the research of the requirement of the optical system based on AFSSI-C to realize centimeter-level imaging classification in the daily experimental test scene.Firstly,the principle of adaptive classification spectral imager is analyzed.According to the interaction between the optical system and the signal processing system of the system instrument,and taking the image classification process as an example,the working principle of the system is analyzed.According to the principle of double grating dispersion and the optical path of spectral imaging,the optical path of the system is constructed.Based on the characteristic state of spectral datacube under the instrument,the classification principle of optical system is analyzed.According to the spectral intensity distribution of the light source and the matching relationship among the light source pixel,DMD pixel and detector pixel,the optical structure and modulated transmission model of spectral signal based on DMD are constructed,which provides theoretical basis for engineering design.Secondly,aiming at the serious chromatic aberration caused by DMD and grating,the ray tracing method is used to analyze the imaging process,and a method to solve the vertical chromatic aberration by matching the focal length and the axial chromatic aberration by reversing the axial dispersion is proposed,which solves the problem that the chromatic astigmatism in the optical system can not be completely compounded.At the same time,according to the simulation software,the effectiveness of the proposed scheme is verified.Finally,the optical system of the adaptive classification spectral imager based on DMD is designed.According to the application scenario analysis,a beam splitting system with a spectral range of 400 nm?800 nm and a spectral resolution of 5 nm is designed.Combined with the analysis of the problem that astigmatism can not be completely compounded,an optical system of adaptive classification spectral imager is designed,which has a focal length of 80 mm for the collimator and imaging mirror of the beam splitting system,73.5 mm for the collimator and imaging mirror of the beam combining system,and a system F number of 4.MTF of the optical system is better than 0.5 at Nyquist frequency,and the imaging quality is good,which can meet the relevant application requirements.