Underwater image enhancement method using weighted guided trigonometric filtering and artificial light correction.

We propose the guided trigonometric filter to refine the coarse depth transmission map.The single de-vignetting method is introduced to remove the footprint.The spectral properties-based color correction method is proposed to recover the scene color. This paper describes a novel method for enhancing optical images using a weighted guided trigonometric filter and the camera's spectral properties in turbid water. Absorption, scattering, and artificial lighting are three major distortion issues in underwater optical imaging. Absorption permanently removes photons from the imaging path. Scattering is caused by large suspended particles found in turbid water, which redirect the angle of the photon path. Artificial lighting results in footprint effects, which cause vignetting distortion in the captured image. Our contributions include a novel deep-sea imaging method that compensates for the attenuation discrepancy along the propagation path, and an effective underwater scene enhancement scheme. The recovered images are characterized by a reduced noise level, better exposure of dark regions, and improved global contrast such that the finest details and edges are significantly enhanced. Our experiments showed that the average Peak Signal to Noise Ratio (PSNR) improved by at least 1dB when compared with state-of-the-art-methods.