Underwater Imaging by Suppressing the Backscattered Light Based on Mueller Matrix

Polarimetric imaging is an effective way for enhancing the image quality in underwater environments. Previous polarization-based methods for underwater imaging actually involve both optical and digital processing, while compared with digital processing, the importance of the optical method is not clear. In this paper, we propose a polarimetric method for underwater imaging based on the Mueller imager. In this method, in order to optimally filter out the backscattered light and enhance the image quality, the polarization states of illumination light together with the polarization filter in front of the camera are synergistically modulated in an optical way. In other words, the quality of images captured by the camera can be directly improved without any digital processing. A series of experimental results show the effectiveness of the proposed method, which indeed verifies its superiority in scattering media.