Visibility improvement of underwater turbid image using hybrid restoration network with weighted filter

• Published in: Multidimensional systems and signal processing 2022-06, Vol.33 (2), p.459-484
• Main Authors: Muthuraman, Dhana Lakshmi, Santhanam, Sakthivel Murugan
• Format: Article
• Language: English
• Subjects: Algorithms; Artificial Intelligence; Artificial neural networks; Circuits and Systems; Color; Electrical Engineering; Engineering; Evaluation; Fisheries; Generative adversarial networks; Image contrast; Image enhancement; Image quality; Image restoration; Light attenuation; Pixels; Signal,Image and Speech Processing; Underwater; Visibility; Water purification
• ISSN: 0923-6082; 1573-0824
• DOI: 10.1007/s11045-021-00795-8

Due to the attenuation of light passes through water, the captured underwater images suffer from low-contrast, halo artifacts, etc. To address this issue, the hybrid network with a weighted filter is proposed to improve the visibility of the obscured (turbid) images. In the captured image, the brighter pixels (near-to-source) are called foreground regions and the darker pixels (far-from-source) are called background regions. In order to ensure the adaptability of the proposed algorithm, the considered datasets are collected on different atmospheric light such as pond, lake, and fisheries tank . The foreground area of an image can be enhanced using the thresholding and masking technique. The background hazy region can be recovered by a hybrid Dehazenet called Generative Adversarial Network and Convolutional Neural Network. With this, the transmission map with high accuracy and color deviation can be addressed. Then both the regions are blended and the Amended Unsharp Mask filter is used to toughen the distorted edges. Finally, the blended restored image is weighted with a contrast factor to obtain the visibility improved image. The subjective and objective evaluation is done on considering the standard non-reference metric called Underwater Image Quality Measure comprises measures of color, sharpness, and contrast for a variety of water types with different atmospheric light. It is observed that the proposed technique showed a metric improvement of 57% compared to other existing techniques in an average manner. Overall, it is inferred that the proposed technique produces better results in both subjective and objective evaluation, thus it outperforms other state-of-the-art techniques.