Research On The Restoration Methods Of Underwater Images

Marine information plays an important role in the exploitation of oceanic resources.Among various kinds of information,underwater image information is one of the most essential ways of exploring the ocean by using computer vision.Underwater images present the true underwater scene intuitively,and can be applied to underwater environment monitoring,resource probing,autonomous underwater vehicle,etc.However,underwater images typically suffer from low contrast and severe color cast.The degradation problem causes not only unpleasing visibility,but also difficulty in subsequent scientific missions,such as feature extraction and image classification.Underwater image restoration method restores the image from the input image by image prior and optical formation model.Overcoming the physical limitation of lowcost imaging devices and complex environment,the technology of underwater image restoration improves the contrast,color fidelity,and signal to noise ratio of the input images.In this paper,we study the existing underwater image restoration methods and propose a method to handle the scattering and absorption problems of light with different wavelengths based on the color-line model.We filter out image patches that exhibit the characteristics of the color-line prior,and recover the color-line of the patches.Then,the local transmission for each patch is estimated based on the offsets of the color lines along the background-light vector from the origin.We also develop an optimization function to derive the local transmission and to obtain the solution in the underwater environment.Experimental results are presented to show that the proposed method can produce high quality underwater images with relatively genuine colors,natural appearance,and improved contrast and visibility.