On-orbit self-adaptive focusing method for space optical camera

Abstract

The invention discloses an on-orbit self-adaptive focusing method for a space optical camera, which comprises the following steps of: (1) using the space optical camera to shoot an image against the ground when the defocusing amount of the camera is adjusted once during an on-orbit automatic focusing process, and obtaining sequential images after shooting for multiple times; (2) calculating displacement amount between two adjacent images by a registration algorithm to find overlaps of the two adjacent images; (3) evaluating and calculating image definitions of the overlaps to obtain a plurality of groups of image definition evaluation values which takes two adjacent images as a group; and (4) mapping the definition evaluation values of a series of images to the same evaluation system by transmitting on a basis that every two adjacent groups of images have the same image definition evaluation value so as to find the best focusing position. The method can enable the space camera to finish automatic focusing within a short period of time during an on-orbit moving process, and is suitable for an application field with short focusing time and high focusing frequency.

Description

technical field [0001] The invention relates to a method for adaptive focusing of a space optical camera during orbital movement. Background technique [0002] During the flight of the space remote sensing camera in orbit, due to the influence of the space environment, air pressure changes, shocks and vibrations during the launch process, the focal plane of the camera will change beyond the allowable range, and then defocus will occur. Therefore, adopting effective auto-focus technology is one of the key technologies to ensure high-quality images captured by remote sensing cameras. The focus of traditional digital cameras is done in a relatively static environment, but the biggest difficulty in focusing space cameras is that they are constantly revolving around the earth. [0003] The space camera is moving in orbit, so the scenes in the images taken at intervals are not exactly the same, and the direct definition evaluation calculation will cause misfocusing problems due t...

AI Technical Summary

Problems solved by technology

The repeated shooting method can accurately focus, but it takes a long period of time for a complete focus, which is not suitable for satellite systems with high real-time requirements such as agile satellites

Although the method based on power spectrum focusing can achieve focusing in a short time, its theoretical basis is that any scene has a similar power spectrum, but in fact this is not entirely the case. The power spectrum differences of forests, oceans, cities, etc. are still relatively large , so this method has relatively large limitations, and the success rate of focusing may be relatively low

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