A novel biologically-inspired method for underwater image enhancement

Underwater images are usually characterized by color distortion, blurry, and severe noise, because light is severely scattered and absorbed when traveling in the water. In this paper, we propose a novel method motivated by the astonishing capability of the biological vision to address the low visibility of the real-world underwater images. Firstly, we simply imitate the color constancy mechanism in photoreceptors and horizontal cells (HCs) to correct the color distortion. In particular, HCs modulation provides a global color correction with gain control, in which light wavelength-dependent absorption is taken into account. Then, to solve the problems of blurry and noise, we introduce a straightforward and effective two-pathway dehazing method. The core idea is to decompose the color corrected image into structure-pathway and texture-pathway, corresponding to the Magnocellular (M-) and Parvocellular (P-) pathway in the early visual system. In the structure-pathway, we design an innovative biological normalization model to adjust the dynamic range of luminance by integrating the bright and dark regions. By using this approach, the proposed method leads to significant improvement in the contrast degradation of underwater images. Additionally, the detail preservation and noise suppression are implemented on the textural information. Finally, we merge the outputs of structure and texture pathways to reconstruct the enhanced underwater image. Both qualitative and quantitative evaluations show that the proposed biologically-inspired method achieves better visual quality, when compared with several related methods. © 2022 Elsevier B.V.