Method for precisely measuring focal distance of superlong-focal-distance space camera

Abstract

The invention discloses a method for precisely measuring focal distance of a superlong-focal-distance space camera, relates to the technical field of optical measuring methods and solves the problem that an existing method for measuring the focal distance of a long-focal-distance space camera is low in measuring accuracy, high in expense needed by supporting equipment and the like. The method includes adopting a spherometer to measure curvature of a spherical standard lens of an interferometer, adopting a mirror surface locator to measure lens thickness of the standard lens, and calculating focal distance of the spherical standard lens of the interferometer according to the curvature radius and the lens thickness which are acquired; adopting the mirror surface locator to measure length of a standard ruler, and placing the standard ruler after length measuring on a two-dimensional adjusting platform; placing the measured camera, a plane mirror and the standard ruler in front of the interferometer, performing coarse adjusting, and performing precise adjusting on the plane mirror; enabling an interferogram of the measured camera to image on a detector of the interferometer; adopting a four-quadrant analysis method to calculate an image on the detector, and acquiring length of an image of the standard ruler; acquiring the focal distance of the measured camera according to the focal distance of the dry standard lens, the length of the standard ruler and the length of the image of the standard ruler.

Description

technical field [0001] The invention relates to the technical field of optical measurement methods, in particular to a method for measuring the focal length of an ultra-long focal length camera. Background technique [0002] At present, in the fields of space-to-ground remote sensing and space photography, both military and civilian fields are striving to develop high-resolution space cameras. When the orbital height of the space camera and the CCD pixel size are constant, increasing the focal length can improve the resolution of the pixel on the ground, but as the focal length increases by nearly 10m, there is currently no supporting testing equipment in China that can accurately measure the focal length. [0003] The Hubble Telescope, a joint project between NASA and the European Space Agency (ESA), has a focal length of 57.6m. The James Webb Space Telescope (JWST) jointly developed by NASA and the European Space Agency (ESA) has a focal length of 108m. The Chandra X-ray...

AI Technical Summary

Problems solved by technology

[0010] The present invention provides a precision measurement method for the focal length of an ultra-long focal length space camera to solve the existing problems of low measurement accuracy and high cost of supporting equipment when measuring the focal length of a long focal length camera

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