Fast defogging algorithm based on local histogram enhancement

A histogram and fast technology, applied in the field of computer vision, can solve problems such as dimming, image brightness reduction, object light is not as good as atmospheric light, etc., and achieve high calculation efficiency, simplified cumbersome steps, and good processing effects

Inactive Publication Date: 2016-08-10
HUNAN VISION SPLEND PHOTOELECTRIC TECH
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Problems solved by technology

[0004] At the same time, due to the participation of atmospheric light components in imaging in foggy days, the overall image appears off-white. The brightness of the image after defogging is reduced, and the color is darker than the actual scene image, so the image brightness needs to be adjusted

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  • Fast defogging algorithm based on local histogram enhancement
  • Fast defogging algorithm based on local histogram enhancement
  • Fast defogging algorithm based on local histogram enhancement

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Embodiment 1

[0033] Embodiment 1: Taking the defogging of a common single image as an example, the present invention will be further described in detail in conjunction with the accompanying drawings.

[0034] Compared with the global histogram equalization enhancement, the local histogram equalization enhancement can usually have a better restoration effect on the concerned local area in the image scene with variable depth of field.

[0035] The first step: do black level processing on the image to be processed, and subtract the fixed black level (offset) to obtain the original image to be processed; since each image input by the CMOS original will be added with a preset initial value, only The fixed value needs to be subtracted to obtain the input original image.

[0036] The second step: correct the image to be processed based on Gamma correction; Gamma correction is to edit the Gamma curve of the image to perform nonlinear tone editing on the image, detect the dark part and light part i...

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Abstract

For the specific problem of image defogging, the invention provides a fast defogging algorithm based on local histogram enhancement to improve the accuracy of the defogging algorithm and the efficiency of algorithm operation, so that the defogging algorithm meets a real-time requirement. The defogging algorithm comprises the steps that black level processing is carried out on an image to be processed, and fixed black level is subtracted; the image to be processed is corrected based on gamma correction and sub block partition is carried out on the image to be processed to carry out gray scale statistics; limited gray-scale stretch is carried out; and finally, pixel by pixel mapping is carried out to acquire a stretched clear fog-free image of high comparison. According to the algorithm provided by the invention, a limited local histogram equalization enhancement method is used; pixel by pixel gray-scale mapping is carried out on the image; four adjacent sub blocks are weighted to acquire the mapping relationship between arbitrary points, and finally the fog-free image of high comparison is output; through the simple mapping relationship, image computation is simplified; the algorithm efficiency is improved; and through pixel by pixel processing, the effect of image defogging is greatly improved.

Description

technical field [0001] The invention relates to the field of computer vision, in particular to a fast defogging algorithm based on local histogram enhancement. Background technique [0002] Most outdoor vision systems, such as video surveillance, target recognition and satellite remote sensing monitoring, etc., need to obtain clear image features. However, under foggy weather conditions, due to the low visibility of the scene, the contrast of the image is reduced, and the target is blurred, so that the imaging system cannot work normally. Therefore, it is of great research value to study how to effectively process fog images and reduce the impact of weather conditions on imaging systems. [0003] Since the distribution of fog is generally uneven, most of the current defogging methods lead to unsatisfactory local effects after defogging, and the details are not obvious. Therefore, it is necessary to perform enhancement processing, so that the overall contrast of the image i...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06T5/40
CPCG06T5/40
Inventor 谭树人张斯尧马昊辰
Owner HUNAN VISION SPLEND PHOTOELECTRIC TECH
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