Aviation camera focus detection device and method based on Shack-Hartmann wavefront sensing

Abstract

The invention provides an aerial camera focus detection device and method based on Shack-Hartmann wavefront sensing. On the premise of not introducing extra measuring elements, focal plane detection in a full aperture range of an optical system can be realized, the requirements on the installation position of a Shack-Hartmann wavefront sensor and the control precision of a scanning mirror are not high, and the device and the method are particularly suitable for an aviation imaging environment. A Shack-Hartmann wavefront sensor is placed in front of an entrance pupil of an optical system of an aviation camera, such as above a scanning mirror, so that structure miniaturization of the aviation camera is facilitated, and the problems that an aviation camera optical system is compact in image space, and a focus detection grating, a light source assembly and a photoelectric receiving device cannot be placed at the same time for a traditional photoelectric auto-collimation focus detection method can be solved.

Description

technical field [0001] The invention belongs to the technical field of aerial camera testing and imaging, and in particular relates to an aerial camera focusing device and method based on Shack-Hartmann wavefront sensing. Background technique [0002] Aerial cameras will be affected by the natural environment (such as atmosphere, temperature, terrain) and the flight attitude of the carrier aircraft during the working process, causing the position of the photosensitive surface of the imaging detector to deviate from the ideal image plane, seriously affecting the clarity and resolution of the image. Therefore, in order to obtain high-definition images, it is necessary to check and adjust the focus before the aerial camera imaging. [0003] The commonly used focusing method for aerial cameras is the photoelectric self-collimation method. In this method, a Ronchi grating is placed on the image plane and illuminated by a light source. The path is returned and imaged on the recei...

AI Technical Summary

Problems solved by technology

[0004] In the field of focus detection of lithography machines, the patent application No. 201410479415.1 discloses a focus detection method based on the Hartmann wavefront detection principle, which is used to detect the position of the silicon wafer in the lithography machine system in real time. The focus detection system includes a light source and collimator beam expander system, front lens group, tested silicon wafer, rear lens group, microlens array and CCD detector. Poor; the patent application with application number 201910426968.3 discloses a large field of view image clearing device and method based on a focal plane Hartmann wavefront sensor. The measurement device described in the method includes a beam splitter, a focal plane Hartmann wavefront The sensor, image acquisition device and image processing module, the spectroscope divides the target information into two, and receives them respectively through the imaging detector and the Hartmann wavefront sensor, and restores each field of view through the information detected by the Hartmann wavefront sensor The wavefront information of the imaging detector is used to clear the image collected by the imaging detector through the image processing method. The application describes the characteristics of the aerial image in the background technology, but does not point out the specific implementation method of this method in the aerial camera. , according to the description of the solution in the patent application, the measurement device is arranged in the image space of the imaging lens, which requires the size of the image space of the aerial camera optical system to be large enough, and the application does not indicate how effective the solution is, and the timeliness is important for the aerial image Focusing is critical

[0005] In summary, the existing self-collimation focus detection method for aerial cameras needs to occupy a large image space of the optical system, and cannot achieve full-aperture detection of the optical system, and the focus detection accuracy is limited; the existing detection method based on the Hartmann sensor The measuring device of the focus method is relatively complicated, and has not been applied in the field of focus detection of aerial cameras.

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