L-CLAHE Intensification Filter (L-CIF) Algorithm for Underwater Image Enhancement and Colour Restoration

Abstract

Contrast degradation due to wavelength-based light attenuation compromises quality of sub-aquatic images. In this paper, L-CLAHE Intensification Filter (L-CIF) algorithm is proposed to improve the quality of underwater images and to enhance underwater images in pre-processing stages. The proposed algorithm consists of three modules, named L-CLAHE, intensification, and filtering. The input image is converted to L*a*b colour space. CLAHE algorithm is used to process the extracted L* channel. The output of L-CLAHE module is processed with gamma correction, histogram equalization and bilateral filter in intensification and filter stages. The output image is contrast improved and colour corrected.