Underwater image enhancement processing method

Abstract

The invention discloses an underwater image enhancement processing method. The method comprises steps of firstly, using the local shade of Gray algorithm to calculate background light of a to-be-processed image; based on an underwater image imaging model, judging whether to add information of a red channel into the dark channel prior by setting a threshold value; meanwhile, by considering the effects of an artificial light source, judging whether an artificial light source exists or not according to the foreground and background brightness of the image, and if the artificial light source exists, adding a saturation degree index and improving the dark channel prior; by use of the relation between the scattering coefficient and the wavelength, estimating the scattering rate, and according to attenuation coefficients of three channels, estimating the attenuation rate; and finally obtaining a restored clear image. According to the invention, disadvantages caused by the fact that the attenuation rates of blue and green channels are assumed to be consistent with each other in the current methods can be overcome; effects caused by the artificial light source, white objects and noise can be effectively avoided; contrast ratio of the image can be effectively enhanced; and a color cast problem caused by inaccurate estimation of the transmittivities of three channels can be well sovled.

Description

Technical field [0001] The invention belongs to the field of computer image processing, and in particular relates to a method for clearing underwater images. Background technique [0002] When shooting images underwater, the organic matter and suspended particles in the water will absorb and scatter the light, resulting in reduced image contrast, reduced scene visibility, lack of color, etc., which brings great impact to underwater target search, detection, and surveillance. difficult. Therefore, the underwater image sharpening algorithm has become a research hotspot in the field of computer vision application and digital image processing. [0003] According to the specific imaging model, the underwater image sharpening algorithm can be divided into image enhancement method and image restoration method. Image enhancement methods mainly include histogram equalization [1] , Filtering method [2] , Retinex algorithm, etc. [3] . The most typical and effective method of image restorat...

AI Technical Summary

Problems solved by technology

First, based on the underwater image imaging model, by setting the threshold to determine whether to add the information of the red channel to the dark channel prior; at the same time, considering the influence of artificial light sources, it is judged whether there is artificial light source according to the brightness of the foreground and background of the image. For the light source, add the saturation index and improve the dark channel prior to weaken the influence of artificial light sources; use the relationship between the scattering coefficient and the wavelength to estimate the scattering rate, and estimate the attenuation rate according to the attenuation coefficient of the three channels, which can make up for many current methods that assume blue-green The defect that the channel attenuation rate is consistent; use the local shade of Gray algorithm [6] Calculate the background light, which can effectively avoid the influence of artificial light sources, white objects and noise

Images