Marine ecosystem is the largest of earth’s aquatic ecosystems. It includes salt marshes, coral reefs, deep sea, sea floor, etc. To learn deep about the activities taking place inside, underwater imaging is a tool. But these images lack in contrast and brightness leading to the lack of information in the ocean activities. To enhance such low contrast underwater images, Low Contrast Detection Factor (LCDF) is proposed in this study. It uses the value, saturation and hue to enhance the low contrast regions and to restore the color. Quality assessment is done to substantiate the proposed algorithm. It is found that the entropy gives an average of 7.3. No-reference Quality Metrics such as Natural Image Quality Evaluator and Blind/ Referenceless Image Spatial Quality Evaluator shows an average value of 3.6 and 22.5, respectively. The blur metrics shows a value of 0.21. The quality metrics indicates that the naturalness of the underwater image is maintained while the contrast of the underwater image has increased.

中文翻译：

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基于低对比度检测因子的水下图像对比度增强和恢复

海洋生态系统是地球上最大的水生生态系统。它包括盐沼，珊瑚礁，深海，海床等。要深入了解内部发生的活动，水下成像是一种工具。但是这些图像缺乏对比度和亮度，导致海洋活动缺乏信息。为了增强这样的低对比度水下图像，本研究提出了低对比度检测因子（LCDF）。它使用值，饱和度和色相来增强低对比度区域并恢复色彩。进行质量评估以证实所提出的算法。发现熵平均为7.3。无参考质量度量标准（例如自然图像质量评估器和盲/无参考图像空间质量评估器）分别显示平均值3.6和22.5。模糊度量显示值为0.21。质量指标表明在增加水下图像对比度的同时，可以保持水下图像的自然度。