Design of optical system for large-field of view aerocamera

Aiming at the features of complex environment and needing high-resolution imaging in high-speed motion for aerocameras, a large-field of view(FOV) aerocamera optical system was designed. A double Gaussian symmetrical structure was adopted as the optical structure of this system, which expanded the camera's field angle by optical splicing with dual imaging modules, and the built-in focusing was achieved by adjusting the last lens. Throughcontrolling the three working modes of the ground objects reflector, the functions of vertical photograph, automatic focusing and forward image motion compensation for aerocameras were realized, respectively. Meanwhile, the image degradation caused by the changes in environmental conditions such as temperature, air pressure, and altitude during aerial photography was avoided to ensure the imaging quality throughout the FOV was not affected. In this design of the optical system, the full FOV without vignetting was realized, and the maximum distortion of the full FOV was less than 0.5‰. At 91 lp/mm, the modulation transfer function(MTF) was close to the diffraction limit, and the objective lens had the same imaging quality in the full FOV. The experimental results and aerial photography test prove that this optical system has the advantages of clear imaging, large FOV, high reliability, small size and light weight, which satisfies the requirements of the aerocameras to be clearly imaged in a relatively complex aviation environment.