Underwater illumination non-uniform image enhancement method based on alternating direction multiplier method

A technology of alternating direction multipliers and uneven illumination, applied in the field of image processing, can solve the problems of color distortion, low visibility, blurred edges, etc., and achieve the effect of good performance, high image quality, and improved quality.

Pending Publication Date: 2021-08-27
NORTHWESTERN POLYTECHNICAL UNIV
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  • Application Information

AI Technical Summary

Problems solved by technology

However, due to the scattering and absorption of light by water, underwater images often exhibit low visibility, blurred edges, and color distortion.
In addition, the concentrating effect of point light sources in the deep sea and the refraction effect of water surface ripples on natural light will cause serious uneven illumination in underwater images.

Method used

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  • Underwater illumination non-uniform image enhancement method based on alternating direction multiplier method
  • Underwater illumination non-uniform image enhancement method based on alternating direction multiplier method
  • Underwater illumination non-uniform image enhancement method based on alternating direction multiplier method

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specific Embodiment

[0082] 1. For figure 2 The method of the present invention is adopted for underwater images under four different situations of uneven artificial point light source (image 1), weak illumination (image 2), uneven natural illumination (image 3) and natural weak illumination and uneven illumination (image 4). Experimental verification, such as Figure 3-6 , and compared with the four algorithms of VCIP, UDCP, gamma correction (GC), and SSR.

[0083] 2. Estimate the initial illumination maps of the four underwater images respectively, and construct a constrained optimization equation of the augmented Lagrangian framework based on the principle of the alternating direction multiplier method, and obtain an accurate illumination map by iteratively solving the optimization equation.

[0084] 3. According to the Retinex theory, the original underwater image and the precise light map are converted to the logarithmic domain to obtain the reflection image in the logarithmic domain, and t...

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Abstract

The invention discloses an underwater illumination non-uniform image enhancement method based on an alternating direction multiplier method, and the method comprises the steps of converting an image from an RGB color space to a Lab color space when an initial illumination image is estimated, and extracting a brightness component as the initial illumination image; then, on the basis of an alternating direction multiplier method principle, constructing a constraint optimization equation of an augmented Lagrange framework, and solving the optimization equation through iteration to obtain a precise illumination map; according to the Retinex theory, converting an image to be processed and an illumination image to a logarithm domain to obtain a reflection image in the logarithm domain, and then carrying out exponential operation to obtain an enhanced image; and finally, inhibiting underwater noise by using a bilateral filter to obtain a finer underwater enhanced image. According to the method provided by the invention, the quality of the underwater illumination non-uniform image is effectively improved, and compared with similar methods, the method provided by the invention has better performance in the aspects of removing the influence of illumination on the underwater image and retaining image details.

Description

technical field [0001] The invention belongs to the technical field of image processing, and in particular relates to a method for enhancing an image with uneven illumination under water. Background technique [0002] The unknown and complexity of the underwater environment is a major challenge for human beings to develop marine resources. Compared with acoustic detection equipment, underwater vision sensors can intuitively obtain colorful, high-resolution underwater environment and target feature information, and are being widely used in marine technology development and scientific research. However, due to the scattering and absorption of light by water, underwater images often exhibit low visibility, blurred edges, and color distortion. In addition, the concentrating effect of deep-sea point light sources and the refraction effect of water surface ripples on natural light will cause serious uneven illumination in underwater images. Therefore, how to solve the blurring a...

Claims

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Application Information

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IPC IPC(8): G06T7/00G06T7/90G06T5/00
CPCG06T7/0002G06T7/90G06T2207/10004G06T5/90
Inventor 李乐李吉玉张文博刘卫东
Owner NORTHWESTERN POLYTECHNICAL UNIV
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