In this paper, an effective method is proposed for restoring underwater image based on color correction and image sharpening. The main purpose of this method is to improve the visibility of underwater images. Traditional methods generally adopt color balancing method to restore the images. However, we found that color balancing has a poor effectiveness on underwater image when the values of blue channel are greater than other two channels, specially, red channel is great of small than blue channel. Therefore, we propose a hybrid method for color correction process based on a principle that exploits the relationship of three channels (red channel, green channel, and blue channel). On the other words, color balancing will be employed to restore the images when the values of red channel approximate to blue channel, while the DCP-base method will be used if otherwise. To enhance the sharpness of underwater image, we employed a sharpening process based on Maximum a Posteriori (MAP) method when color correction has finished. The proposed method also been validated through carrying out experiments on several underwater image datasets which are provided by previous researchers. Our validation has proved that the proposed method has a better performance than the state-of-the-art methods.

中文翻译：

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一种基于色彩校正和图像锐化的水下图像恢复混合算法

本文提出了一种基于色彩校正和图像锐化的水下图像恢复方法。这种方法的主要目的是提高水下图像的可见度。传统方法一般采用色彩平衡方法来还原图像。然而，我们发现当蓝色通道的值大于其他两个通道时，色彩平衡对水下图像的效果较差，特别是红色通道比蓝色通道大或小。因此，我们基于利用三个通道（红色通道、绿色通道和蓝色通道）的关系的原理，提出了一种用于颜色校正过程的混合方法。换句话说，当红色通道的值接近蓝色通道时，将采用色彩平衡来恢复图像，否则将使用基于 DCP 的方法。为了增强水下图像的清晰度，我们在色彩校正完成后采用了基于最大后验（MAP）方法的锐化过程。通过对先前研究人员提供的几个水下图像数据集进行实验，也验证了所提出的方法。我们的验证证明，所提出的方法比最先进的方法具有更好的性能。