Thermal-optical characteristics analysis of an aerial camera optical system.

Abstract

Ambient temperature is one of the important factors affecting the imaging quality of the optical system. Therefore, it is necessary to analyze the thermal-optical characteristics of the optical system when studying the imaging quality of the optical system. Taking the self-made aerial camera optical system as an example, this paper reports the use of the finite element software ANSYS to analyze the thermal stress of the aerial camera optical system, the use of the homogeneous coordinate transformation method to remove the rigid body displacement caused by the mirror surface, and the performance of a Zernike polynomial simulation on the processed surface data. Together, the Zernike coefficients obtained after the fitting are substituted into the ZEMAX optical software to express the surface shape obtained after deformation to analyze the changes in optical imaging quality under thermal environmental conditions. The results of the experiment show that when the working environmental temperature is 50°C, the (MTF) decreases from 0.371 to 0.315 and, when the working environmental temperature is -40∘C, the MTF decreases from 0.371 to 0.285. The comparison results of the experiment and simulation show that the environmental temperature is heating up or, under the condition of cooling, the imaging quality of the aerial camera will be reduced. The thermal-optical analysis method can be used to simulate the actual use conditions of the aerial camera optical system and predict the imaging quality change trend of the optical system. The method of thermo-optical analysis has important guiding significance for the design of an optical-mechanical system.