Underwater image capturing is a challenging task due to attenuation of light in water. Scattering and absorption are the results of light attenuation which lead to faded colors and reduced contrast of images, respectively. To deal with these issues and to provide better visual quality image, various enhancement methods have been proposed. This paper proposes the Dual Domain-based Underwater Image Enhancement (DDUIE) method. DDUIE method provides contrast stretching in approximation band of discrete wavelet transformed image followed by intensity adjustment of different color channels in spatial domain. To further improve the color quality, the image is processed in HSV (Hue–Saturation–Value) color space. Result analysis indicates better results for DDUIE method over state-of-the-art methods. Subjective results of DDUIE method show minimization of the bluish-green effect and reduction of nonuniform illumination up to a certain extent. These lead to enhanced color and image details. Quantitative results show that the Underwater Image Quality Measure (UIQM) and Underwater Color Image Quality Evaluation (UCIQE) values between 1 and 2 and between 0 and 1 have been achieved, respectively, which significantly illustrate that images have been enhanced efficiently and also entropy values between 7 and 8 depict the effectiveness of the proposed method in terms of image details.

中文翻译：

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非均匀照明水下图像的增强

由于水中的光衰减，水下图像捕获是一项具有挑战性的任务。散射和吸收是光衰减的结果，分别导致颜色褪色和图像对比度降低。为了解决这些问题并提供更好的视觉质量图像，已经提出了各种增强方法。本文提出了基于双域的水下图像增强（DDUIE）方法。DDUIE方法在离散小波变换图像的近似带中提供对比度拉伸，然后在空间域中对不同颜色通道进行强度调整。为了进一步提高色彩质量，图像在 HSV（Hue-Saturation-Value）色彩空间中进行处理。结果分析表明，DDUIE 方法的结果优于最先进的方法。DDUIE方法的主观结果表明，在一定程度上可以最大限度地减少蓝绿色效应并减少不均匀照明。这些导致增强的颜色和图像细节。定量结果表明，水下图像质量测量 (UIQM) 和水下彩色图像质量评估 (UCIQE) 值分别在 1 和 2 之间和 0 和 1 之间，这显着说明图像得到了有效增强，熵值也得到了提升图 7 和 8 之间描述了所提出方法在图像细节方面的有效性。