针对水下图像存在颜色失真和视觉模糊等问题,提出基于光衰减先验和背景光融合的水下图像复原算法。首先通过最大强度先验计算背景光一,基于图像四叉树的方法估计背景光二,根据水下图像光照的亮暗情况对两个局部背景光进行融合,确定全局背景光;其次根据光衰减先验估计场景的相对深度,进而计算三个通道的透射率;然后逆求解水下光学成像模型以消除后向散射;最后结合限制对比度自适应直方图均衡算法以更好地校正水下图像的颜色畸变,最终得到复原后的水下图像。与4种具有代表性的水下图像复原方法进行主客观评价对比实验。实验结果表明,所提算法可以有效去除水下图像的视觉模糊,视觉效果更接近自然场景中的图像。

Aiming at the problems of color distortion and visual blur in underwater images, an underwater image restoration algorithm based on light attenuation prior and background light fusion is proposed. First, the background light 1 is calculated by the maximum intensity a priori, and the background light 2 is estimated by the image quadtree method. The two local background lights are fused according to the brightness and darkness of the underwater image illumination to determine the global background light. Secondly, the relative depth of the scene is estimated a priori according to the light attenuation, and then the transmittance of the three channels is calculated. Then the underwater optical imaging model is solved inverse to eliminate backscattering. Finally, the adaptive histogram equalization algorithm with limited contrast is combined to better correct the color distortion of the underwater image, and finally the restored underwater image is obtained. Conduct subjective and objective evaluation comparison experiments with four representative underwater image restoration methods. The experimental results show that the proposed algorithm can effectively remove the visual blur of underwater images, and the visual effect is closer to the images in natural scenes.