Double Stage Gaussian Filter for Better Underwater Image Enhancement

Major issue in marine environment imaging is the expulsion of hazy scenes caused by natural phenomena such as absorption and scattering in underwater images. The visual appearance of the underwater image needs to be improved. In this paper, a double stage Gaussian filter (DSGF) and fusion-based approach to enhance the underwater images is proposed. In the proposed two stage process for image fusion, first section deals with applying the DSGF with high, low, and medium sigma values on the individual R, G and B components of input RGB images and second section deals with applying colour component wise contrast limited adaptive histogram followed by median filtering. The outputs of these two sections are fused using principal component analysis fusion technique. Fused image is post-processed using the colour contrast correction for better visibility results. Proposed method is compared with single stage Gaussian filter where only one stage of Gaussian filtering is applied for reduced computation, Adaptive histogram equalization and histogram specification methods. Proposed method results in quality images obtained through gradual intensity improvement and contrast correction process. Qualitative and quantitative analysis are performed on the enhanced underwater images to observe the effectiveness of the algorithm used. The performance measures such as entropy, SSIM, and AMBE unveil the verification of the proposed findings.