The Snell’s Window Image for Remote Sensing of the Upper Sea Layer: Results of Practical Application

Abstract

Estimation of water optical properties can be performed by photo or video registration of rough sea surface from underwater at an angle of total internal reflection in the away from the sun direction at several depths. In this case, the key characteristic of the obtained image will be the border of the Snell’s window, which is a randomly distorted image of the sky. Its distortion changes simultaneously under the action of the sea roughness and light scattering; however, after correct “decoding” of this image, their separate determination is possible. This paper presents the corresponding algorithms for achieving these possibilities by the Snell’s window images. These images were obtained in waters with different optical properties and wave conditions under several types of illumination. Practical guidelines for recording, processing and analyzing images of the Snell’s window are also formulated.

Keywords

• underwater vision
• Snell’s window image
• inherent optical properties
• slope variance
• remote sensing