A Hybrid DCT-CLAHE Approach for Brightness Enhancement of Uneven-illumination Underwater Images
Meng Ge, Qingqing Hong, Lifeng Zhang · 2018
Underwater images have been drawing sufficient attentions, as more and more researchers and companies are committed to ocean engineering, underwater archaeology, mining etc in recent years. Underwater images often suffer from unbalanced illumination, which bring image analysis and processing challenges. This paper introduces a novel approach for underwater image enhancement based on the DCT coefficient and CLAHE algorithm. Image changes with operations on the statistical model of the image DCT coefficients. The proposed methods firstly perform brightness equalization of the image, which optimize the underexposed and overexposed regions by regulating the low-frequency part of the image DCT coefficients. Afterwards CLAHE is applied to achieve image contrast enhancement. Finally experiments shows the better image enhancement performance compared to other algorithms.