Contrast enhancement for images in turbid water
Contrast enhancement for images in turbid water
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DOI：
10.1364/josaa.32.000886
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发表时间：
2015-05-01
影响因子：
1.9
通讯作者：
Serikawa, Seiichi
中科院分区：
文献类型：
--
作者：
Lu, Huimin;Li, Yujie;Serikawa, Seiichi
吸收、散射和颜色失真是影响水下光学成像质量的三大因素。光线在穿过水时被吸收，吸收率取决于光的波长。散射是由大的悬浮颗粒引起的，它们总是在水下环境中观察到。由于光在水中通过单位长度时，衰减率与光的波长成反比，因此会发生颜色失真。因此，水下图像是黑暗的，低对比度，并以蓝色为主。本文提出了一种新的水下成像模型，该模型补偿了沿着传播路径的衰减差异，并提出了一种基于彩色谱线的环境光估计器和一种局部自适应滤波算法，用于增强浅海水下图像。此外，我们提出了一种基于光谱特征的颜色校正算法来恢复失真的颜色。增强后的图像具有合理的噪声水平后，在黑暗的区域中的照明补偿，并表现出改善的全局对比度，其中最精细的细节和边缘显着增强。(C)2015美国光学学会
Absorption, scattering, and color distortion are three major degradation factors in underwater optical imaging. Light rays are absorbed while passing through water, and absorption rates depend on the wavelength of the light. Scattering is caused by large suspended particles, which are always observed in an underwater environment. Color distortion occurs because the attenuation ratio is inversely proportional to the wavelength of light when light passes through a unit length in water. Consequently, underwater images are dark, low contrast, and dominated by a bluish tone. In this paper, we propose a novel underwater imaging model that compensates for the attenuation discrepancy along the propagation path. In addition, we develop a robust color lines-based ambient light estimator and a locally adaptive filtering algorithm for enhancing underwater images in shallow oceans. Furthermore, we propose a spectral characteristic-based color correction algorithm to recover the distorted color. The enhanced images have a reasonable noise level after the illumination compensation in the dark regions, and demonstrate an improved global contrast by which the finest details and edges are enhanced significantly. (C) 2015 Optical Society of America