A Retinex-Based Fast Image Restoration Method in Nighttime Fog

Abstract

The invention relates to a fast night-time foggy image restoration method based on Retinex, which processes a single color image in nighttime foggy weather to make the visual perception clear; first, a guided filter with edge-preserving characteristics is used to estimate the value of each color component. Illumination image, calculate the local contrast coefficient; then perform Otsu threshold segmentation on the maximum channel image of the original image, adaptively estimate the Gamma parameter of each pixel, perform Gamma correction and contrast maintenance on the illumination image; finally transform the image into HSV space, The CLAHE algorithm is used to enhance the contrast of the brightness channel V, and then the image is transformed into the RGB space to obtain a restored image; the invention is versatile and universal, and can effectively improve the clarity of the image after defogging and effectively correct the image color cast. Phenomenon, the enhanced image details are clear and the colors are natural.

Description

technical field [0001] The invention relates to the field of image processing, in particular to a Retinex-based fast image restoration method in foggy days at night. Background technique [0002] Fog is a natural phenomenon, which is caused by a large number of tiny water droplets, aerosols and other media suspended in the atmosphere, so that the light reflected from the surface of the object and reaching the camera is attenuated by the scattering of atmospheric particles, so that the contrast of the image collected by the imaging device , desaturation or even hue shift. Under low illumination conditions, if affected by fog, the collected images tend to have low brightness, low contrast and color cast, making image details unrecognizable, which seriously affects the visual effect of the image and the analysis and analysis of the image by the computer vision system. Therefore, it is necessary to enhance the foggy image at night to restore a clear image. [0003] At present,...

AI Technical Summary

Problems solved by technology

This method can highlight image details, but due to the use of global color transformation without considering the image information under different scenes and lighting conditions, there is a color cast in the enhanced results

Another researcher proposes to perform illumination compensation and color correction on the image first, and then use an improved dark channel prior-based dehazing algorithm to enhance the foggy image at night. This method can effectively enhance the brightness and contrast of the image, and overcome the Color cast phenomenon, but due to the dehazing method based on the dark channel prior, the enhanced image sky is prone to block effects

Traditional image defogging methods can no longer meet the restoration requirements of nighttime foggy images, so it is necessary to combine the characteristics of nighttime foggy images to restore the nighttime foggy images, so as to improve the visual effect of the image and facilitate the analysis of the image by the computer vision system and processing

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