Large-aperture aspheric surface measurement system and method based on real-time computer-generated hologram

Abstract

The invention discloses a large-aperture aspheric surface measurement system and a method based on real-time computer-generated hologram. Computer-generated hologram dynamic compensation and sub aperture stitching technology are combined, real-time computer-generated hologram zero position measurement is realized through a spatial light modulator, and high-precision one-time zero position measurement data are acquired; a binocular stereo vision positioning system is adopted for acquiring pose transformation parameters; and finally, by using the pose parameters, all sub aperture data are stitched and merged through a corresponding stitching algorithm to obtain a full aperture measurement result. Quick and high-precision detection on the large-aperture aspheric mirror can be realized, and detection guarantee is finally provided for high-precision processing on the large-aperture aspheric mirror.

Description

【Technical field】 [0001] The invention belongs to the technical field of advanced optical manufacturing and detection, and relates to a large-diameter aspheric mirror computational holographic detection technology, in particular to a large-diameter aspheric measurement system and method based on real-time computational holography. 【Background technique】 [0002] Optical aspheric elements have significant advantages in correcting aberrations, improving image quality, and simplifying systems, making optical aspheric elements more and more popular in astronomical optics, space optics, laser fusion, and various high-tech civilian products. more and more widely used. Due to the complexity and diversity of optical aspheric shapes, the processing of such components must require high-precision aspheric surface detection technology to ensure. Especially for large-diameter aspheric components (400mm and above), the existing measurement methods and technologies can no longer meet the ...

AI Technical Summary

Problems solved by technology

The zero-position interferometry has high measurement accuracy, but this method is one-to-one detection, and the versatility is poor. For a specific aspheric surface, a corresponding zero-position compensator (zero lens or computational holographic CGH) needs to be designed.

The non-null interferometric method is more flexible, but due to the deviation from the zero condition, the asphericity that can be measured by the non-null method is greatly limited. The return error must be corrected to obtain the final surface error, so the measurement accuracy is difficult to guarantee

[0004] In recent years, the real-time computational holographic compensation method based on the spatial light modulator has greatly improved the flexibility of aspheric detection. However, the spatial resolution of the spatial light modulator is not high (about 100 line pairs / mm), which limits its The displayed maximum fringe frequency of the calculated hologram, for a large-aperture high-steep aspheric surface, it is impossible to complete the zero compensation measurement of the aspheric surface at one time

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