Underwater image sharpening method based on underwater imaging model and depth of field

Abstract

The invention discloses an underwater image sharpening method based on an underwater imaging model and a depth of field. The method comprises steps of: firstly, estimating background light by using alocal shade of Gray algorithm so as to avoid influences of an artificial light sources, a white object and noise; then, determining whether to add the information of a red channel to dark channel priori by setting a threshold; estimating a scattering rate by using the depth of field to obtain better contrast and saturation colors; finally, separately solving the transmittances of the RGB channelsby using a relation among the background light, a scattering coefficient and an attenuation coefficient and finally obtaining a sharpened image. The method of the invention can compensates a defect inconventional methods which supposes that the RGB channels have the same transmittance, enhance the contrast of the image, and can well solve color deviation caused by inaccurately estimated transmittances of the three channels.

Description

technical field [0001] The invention belongs to the field of computer image processing, in particular to a method for clearing underwater images. Background technique [0002] Underwater images play a very important role in the fields of marine energy exploration, marine environmental monitoring and protection, and marine military. However, due to the special underwater environment, it is difficult to obtain high-quality underwater images. Organic matter dissolved in water and particles suspended in water will absorb and scatter light, resulting in a decrease in image contrast, a reduction in the visible range of the scene, and a reduction in image quality [1] . Therefore, the problem of underwater image clarity needs to be solved urgently in the field of computer vision applications and digital image processing. [0003] According to whether it is based on a specific imaging model, the underwater image sharpening algorithm can be divided into image enhancement methods an...

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Problems solved by technology

[0015] In view of the above problems, the present invention provides an underwater image clearing method based on the underwater imaging model and the depth of field. Considering the attenuation difference of the three channels, based on the new underwater image imaging model, firstly, the local shade of Gray algorithm is used to estimate the background light, which can Effectively avoid the influence of artificial light sources, white objects, and noise; then, by setting the threshold to determine whether to add the information of the red channel to the dark channel prior; using the depth of field to estimate the scattering rate can make the estimation of the scattering rate more accurate. Produce better clear images, get better contrast and saturation colors, which can make up for the inaccurate estimation of transmittance by many current methods; use the relationship between background light, scattering coefficient, and attenuation coefficient to separate the RGB three channels Solving the transmittance can make up for the defect that many current methods assume that the transmittance of the RGB three channels is the same

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