Method for compensating uneven brightness of bottom view image under nighttime infrared

Abstract

The invention belongs to the technical field of information processing, and particularly relates to a method for compensating uneven brightness of a bottom view image under nighttime infrared. Compared with the prior art, the method comprises the following steps of extending an original image by fully utilizing a mirror image method of an image, and eliminating edge effect influence of the image; using an average filter to acquire a background image of an extracted image, and removing texture details of the background image as far as possible; utilizing a difference method to eliminate the phenomenon of uneven brightness of four corners of the image, so that the algorithmic complexity is reduced, and the timeliness of the algorithm is improved; and adopting image contrast enhancement process on the differenced image, so that a gray value distribution range of the image is expanded.

Description

technical field [0001] The invention belongs to the technical field of information processing, and in particular relates to a method for compensating the brightness unevenness of an infrared down-view image at night. Background technique [0002] The image matching navigation system based on down-looking images is an aircraft that performs positioning or navigation by matching reference images prepared by satellites or aerial photography with down-looking infrared images captured in real time. [0003] Scene matching mainly includes image source selection and image feature extraction, similarity measurement, matching search strategy, false matching discovery, etc. Among them, the algorithms for directly matching according to image pixel values ​​include template matching algorithm, fast Fourier algorithm and so on. This algorithm is simple and easy to implement, but the amount of calculation is usually very large, and it is also greatly affected by the lighting conditions w...

AI Technical Summary

Problems solved by technology

If the real-time image has uneven brightness distribution or serious noise interference, etc., this will seriously affect the results of image processing, which in turn will affect the effectiveness of the selected method, and cause false matching in severe cases.

[0005] In low temperature nighttime environment, such as figure 1 As shown, due to the uneven temperature difference, the image captured by the infrared imager is dark in the middle and bright in the four corners

The inhomogeneity of image brightness will seriously affect the extraction and analysis of image feature points and textures by image processing algorithms, resulting in the lack of necessary feature information for real-time images to match with reference images, resulting in inability to perform scene matching, or mismatch

[0006] In the case where infrared images at night are mainly used in the downward-looking scene matching of aircraft, if the infrared downward-looking images with uneven brightness at night are directly applied to the downward-looking scene matching, image features and textures may not be extracted, and mismatching may occur. Successful or incorrect matching, so in order to improve the accuracy of matching, it is necessary to compensate the uneven brightness of the image

At present, there are many methods to compensate the unevenness of image brightness, but some methods are effective, but the algorithm is more complicated and not suitable for real-time use requirements; some methods are simple and satisfy real-time performance, but the effect is not good, and there are edge effects

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