Design Of Optical System For Wide Band Multispectral Camera

Spectral imaging technology uses different spectral information to obtain the physical properties of the target,improves the accuracy and sensitivity of target detection,and expands the detection ability of traditional imaging system.The fusion of wide band navigation and multispectral imaging technology has a very important application value in the field of star mapping,environmental monitoring and so on.In this paper,we will study the system which requires wide band composite and multispectral imaging at the same time,and provide the combination of navigation function and spectral imaging analysis function.The system uses the filter wheel to share a camera.The multi spectral segment image of the target is obtained by rotating the filter in the filter wheel.The wide spectral segment navigation image information is obtained by using the white film position in the filter wheel.Firstly,based on the chromatic aberration correction theory and the dispersion characteristic diagram of the optical glass,the chromatic aberration equation of the wide band optical system is derived.Based on this principle,the glass materials are selected reasonably,and the initial structural parameters of the system are calculated,and the chromatic in the wide band optical system is corrected reasonably.The system requires clear imaging for different distance targets,In order to achieve this goal,the internal focusing design of the system is carried out.In order to solve the problem of color difference stability in the process of internal focusing,a mathematical model of chromatic aberration correction in internal focusing is established.In this paper,a design method of an internal focusing wide spectrum optical system is proposed,and the influence of different focal distribution on the variation of the distance between components in the system is analyzed.Finally,on the premise of realizing the excellent image quality of internal focusing,the number of moving components is reduced,which is beneficial to the subsequent adjustment and can reduce certain power consumption.Finally,a wide spectral range multispectral camera optical system with a spectrum range of 400～1000nm and an F number of 2.8 is designed.Through the correction and compensation of the position chromatic aberration and the secondary spectrum of the system,the transfer function of the system is 0.42 at the 145lp/mm Nyquist frequency,and the encircling energy is more than 80% within the 7μm radius,which can realize the focusing and imaging of objects at different positions of 0.2～200km.After comprehensive analysis,the imaging quality meets the design requirements,the correctness of the established mathematical model and the derived formula is verified.Finally,the analysis of the optical system is carried out,and the analysis results show that the system is feasible.