Underwater image quality enhancement through Rayleigh-stretching and averaging image planes

• Main Authors: Ghani Ahmad Shahrizan Abdul, Isa Nor Ashidi Mat
• Format: Article
• Language: English
• Published: Elsevier 2014-12-01
• Series: International Journal of Naval Architecture and Ocean Engineering
• Subjects: Underwater image processing; Histogram modification; Contrast enhancement; Noise reduction
• Online Access: http://www.degruyter.com/view/j/ijnaoe.2014.6.issue-4/ijnaoe-2013-0217/ijnaoe-2013-0217.xml?format=INT

Visibility in underwater images is usually poor because of the attenuation of light in the water that causes low contrast and color variation. In this paper, a new approach for underwater image quality improvement is presented. The proposed method aims to improve underwater image contrast, increase image details, and reduce noise by applying a new method of using contrast stretching to produce two different images with different contrasts. The proposed method integrates the modification of the image histogram in two main color models, RGB and HSV. The histograms of the color channel in the RGB color model are modified and remapped to follow the Rayleigh distribution within certain ranges. The image is then converted to the HSV color model, and the S and V components are modified within a certain limit. Qualitative and quantitative analyses indicate that the proposed method outperforms other state-of- the-art methods in terms of contrast, details, and noise reduction. The image color also shows much improvement.