Low illumination color image enhancement method

Abstract

A low illumination color image enhancement method base on Retinex theory is disclosed. That low illumination color image enhancement method assume that the original image is obtained by product of illumination image and reflection image, and obtains a smooth image of the original image by image smoothing. Adding a constant to the obtained smooth map to obtain the required illumination map; the three channel images of the original color image are divided by the illumination image to obtain the reflection images of the three channel images. A new illumination map is constructed by adding a constant to the mean value of pixel gray of the original image. Finally, the three-channel reflectance images are multiplied by the new illumination images, and then the three channels are merged to obtainthe final enhanced images. A low illumination image enhancement algorithm base on Retinex theory can generate halo and dark area color mosaic phenomenon at that same time of image enhancement, so that a more natural enhancement image can be obtained, the algorithm step and theory are simple, the programming is easy to realize, and the real-time performance of the algorithm is guarantee.

Description

technical field [0001] The invention relates to an image enhancement method, in particular to a low-illuminance color image enhancement method, which belongs to the technical field of digital image processing. Background technique [0002] A low-light image refers to an image that is completely or partially dark due to low light or unbalanced lighting conditions, such as an image captured at dusk or under low-light conditions. Like this, low-illuminance images caused by brightness imbalance seriously affect people's observation or computer processing of images. After the low-brightness image is enhanced, the brightness of the image can be adjusted, the details of the darker area in the image can be reproduced, and the computer can perform a better analysis and processing of the image. At present, low-brightness image enhancement has been widely used in remote sensing images, medical images, sonar images, video processing, photographic images, etc. In recent years, many low...

AI Technical Summary

Problems solved by technology

However, this method is only suitable for globally darker images, and is not suitable for locally darker areas, which will over-enhance such images and distort the image

[0005] ③Enhancement algorithm based on Retinex model: the present invention utilizes this algorithm exactly, but halo will appear in the image enhanced with this method now, and " mosaic " phenomenon can appear in the particularly dark place of image, and algorithm is loaded down with trivial details

However, this method will cause loss of image details and image distortion

[0007] ⑤Dark channel defogging theory algorithm: This type of method can achieve a certain image enhancement effect, but because it is difficult to control the parameter size in the defogging theory, there may be improper image enhancement, color distortion and artificial processing traces.

[0008] To sum up, the current low-light image enhancement algorithm will cause color distortion, halo, excessive contrast enhancement, etc. in the enhanced image while enhancing the image, and some algorithms are time-consuming, cumbersome to program, and the algorithm is not real-time

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