基于OTSU分割和融合的非均匀光照水下图像增强

针对深海和夜间水域补充照明造成的水下图像光照不均,水中悬浮颗粒造成的图像 噪声、低对比度、偏色等问题,提出一种新的非均匀光照水下图像增强方法。首先,用高 斯滤波去除水下图像的噪声；其次,用最大类间方差法(大律法,maximum inter class variance, OTSU)分割出图像的明暗区域 掩膜,将亮度图分割成明暗区域,并对暗区域进行同态滤波处理,校正光照不均造成的阴 影；接着,用加权平均法融合明暗区域得到新的亮度图,重新合成彩色图像；最后,对水 下图像用对比度受限自适应直方图均衡化(contrast limited adaptive histogram equalization, CLAHE)和灰度世界进行增强对比度和颜色失 真校正,得到增强的水下图像。实验结果表明,本文提出的算法能够有效的改善光照不均 问题,并去除水下图像噪声、增强图像对比度,有利于后续目标检测、追踪等任务的进 行。

Underwater image enhancement with nonuniform illumination based on OTSU segmenta tion and fusion

Aiming at the problems of uneven illumination of underwater image cause d by supplementary illumination of deep sea and night waters,image noise,low contra st and color deviation caused by suspended particles in water,an underwater image enhancemen t method with nonuniform illumination is proposed.Firstly,the noise of underwater ima ge is removed by Gaussian filter.Secondly,the maximum inter class variance (OTSU) method is used to segment the light and dark region mask of the image, divide the brightness map into light and dark regions, and homomorphic filtering is performed on the dark regions to correct the shadows caused by uneven illumination. Then,the new brightness map is obtained by fusing the light and dark areas with weighted aver age method, and the color image is synthesized again.Finally,the underwater image is proce ssed with contrast limited adaptive histogram equalization (CLAHE),and gray world to enhan ce contrast and color distortion correction,get enhanced underwater image.The exp erimental consequences express that the proposed method can valid ameliorate the uneven illumination problem,remove the underwater image noise and enhance the image co ntrast, which is conducive to the subsequent target detection,tracking and other tasks.