Sabbah Shai, Shashar Nadav
Interuniversity Institute for Marine Sciences in Eilat and Department of Evolution, Systematics and Ecology, Hebrew University of Jerusalem, Israel.
Appl Opt. 2006 Jul 1;45(19):4726-39. doi: 10.1364/ao.45.004726.
The underwater light field is an ever-changing environment. Surface waves induce variability in the radiance and the light's polarization. We examined the dependence of the polarization fluctuations associated with diffuse light (not including contribution from direct skylight) on the viewing zenith angle (30 degrees, 70 degrees, and 90 degrees), solar zenith angle (23 degrees -72 degrees), depth of 0.5-3 m, and light wavelength (380-650 nm) while observing within the azimuthal plane in the wind-wave direction. Polarization and radiance fluctuated with time. Light variability (presented by the coefficient of variation calculated over a series of fluctuations in the radiance and percent polarization, and by the standard deviation calculated over a series of fluctuations in the e-vector orientation) was highest at a viewing zenith angle of 70 degrees , depended positively on the solar zenith angle, and decreased with depth at viewing zenith angles of 30 degrees and 70 degrees . Additionally, the variability of the percent polarization was significantly higher than that of the radiance. The temporal light fluctuations offer possibilities, such as enhancing the detection of transparent and reflecting objects; however, they set constraints on the optimal underwater polarization vision by both animals and by the use of instruments.
水下光场是一个不断变化的环境。表面波会导致辐射度和光的偏振发生变化。我们在风浪方向的方位平面内进行观测时，研究了与漫射光（不包括直接天光的贡献）相关的偏振波动对视顶角（30度、70度和90度）、太阳天顶角（23度 - 72度）、深度0.5 - 3米以及光波长（380 - 650纳米）的依赖性。偏振和辐射度随时间波动。光的变化性（由辐射度和偏振百分比的一系列波动计算得出的变异系数以及由e向量方向的一系列波动计算得出的标准差表示）在视顶角为70度时最高，与太阳天顶角呈正相关，并且在视顶角为30度和70度时随深度减小。此外，偏振百分比的变化性显著高于辐射度的变化性。光的时间波动提供了一些可能性，比如增强对透明和反射物体的检测；然而，它们对动物以及仪器使用的最佳水下偏振视觉都设置了限制。
