Acta Photonica Sinica, Volume. 53, Issue 2, 0222001(2024)

Design of Optical-mechanical System of Catadioptric Aerial Mapping Camera Based on Secondary Mirror Image Motion Compensation

Hongwei ZHANG, Rui QU, Weining CHEN, and Hongtao YANG*
Author Affiliations
  • Aircraft Optical Imaging and Monitoring and Measurement Technology Laboratory,Xi'an Institute of Optics and Precision Mechanics,Chinese Academy of Sciences,Xi'an 710119,China
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    Aerial surveying and mapping is an important technical means of civil/military surveying and mapping, which can quickly obtain large-scale and high-precision scale mapping of the target area in a short period of time, and accurately obtain coordinate information of the target plane and elevation information on the map. The acquired information plays an important supporting role in digital city construction, land resources survey, military strategic planning, etc. With the development of aerial surveying and mapping technology, the requirements for aerial mapping cameras have been further improved. It is required that aerial mapping cameras can achieve wide width, high precision and large scale mapping. In order to meet the above requirements, the aerial mapping camera adopts scan imaging mode, but this imaging mechanism will introduce forward/scan image motion, which will affect the image quality. In order to satisfy the image stabilization accuracy of the aerial mapping camera, it is necessary to compensate the image motions. Therefore, a catadioptric aerial mapping camera based on secondary mirror image motion compensation is designed in this paper.Aiming at the dynamic image motion problem of the aerial mapping camera in the process of ground swing imaging, the vector aberration theory for a two-mirror telescopic systems is adopted. The secondary mirror is used as the image motion compensation element, and the comprehensive image motion compensation of the aerial mapping camera is realized through the secondary mirror multi-dimensional motion. However, in the process of compensating the image motion, the secondary mirror will be eccentric and inclined, which will cause the secondary mirror to be off-axis and affect the image quality. Therefore, a misalignment optical system model is established to study the relationship between the deviation vector of the secondary mirror field and the misalignment of the secondary mirror field, and the influence of the secondary mirror motion on the image quality is analyzed. Meanwhile, a design example of the optical-mechanical system of the catadioptric aerial mapping camera based on the secondary mirror image motion compensation is given. The effective focal length of the optical system is 450 mm, and the working spectrum is 435~900 nm. The field of view of the optical system is 4.17×3.13, and the F-number is 4.2. In the design process, the optical-mechanical system of aerial mapping camera adopts non-thermal design to adapt to the working environment of -40 ℃~60 ℃.In order to verify the image motion compensation ability of multi-dimensional motion of the optical element, an experimental platform is built to conduct laboratory imaging tests and field imaging tests on the aerial mapping camera. The laboratory imaging test results show that the dynamic resolution of the aerial mapping camera using the image motion compensation technology can reach 74 lp/mm, and the image motion compensation accuracy is better than 0.5 pixels, which meets the design expectation. In addition, the field imaging test results show that compared with disable image motion compensation function, the aerial survey camera with enable image motion compensation function can acquire sharp edges, clear images, and image quality can meet the expected requirements. Therefore, the camera has the advantages of high accuracy of image motion compensation, compact volume and high reliability, which lays a theoretical foundation for the direction of light and small, high precision and large scale mapping.

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    Hongwei ZHANG, Rui QU, Weining CHEN, Hongtao YANG. Design of Optical-mechanical System of Catadioptric Aerial Mapping Camera Based on Secondary Mirror Image Motion Compensation[J]. Acta Photonica Sinica, 2024, 53(2): 0222001

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    Paper Information

    Category: Optical Design and Fabrication

    Received: Jul. 18, 2023

    Accepted: Sep. 26, 2023

    Published Online: Mar. 28, 2024

    The Author Email: YANG Hongtao (yanght@opt.ac.cn)

    DOI:10.3788/gzxb20245302.0222001

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