Optics of Distilled and Natural Water

Color Registration of Underwater Images for Underwater Sensing with Consideration of Light Attenuation

“…The light intensity decreases with the distance from objects in water by light attenuation depending on the wavelength of light. Red light decreases easier than blue light in water [2]. For example, there exists red color at the neck of the person in Fig.…”

“…Water whose attenuation coefficients of red, green, and blue colors are 0.4000, 0.0391, and 0.0348, respectively, was adopted as liquid [2]. Attenuation coefficients of every wavelength in air was set zero.…”

“…Therefore, underwater robots or underwater sensing systems that work instead of human become important, and technologies for observing underwater situations correctly and robustly from cameras of these systems are needed [1]. However, it is very difficult to observe underwater environments with cameras [2]- [4], because of the following three big problems.…”

Using a Water Lens for Light Concentration in Thermoelectric Generation

“…In addition, optical absorption in water also occurs. [9] However, the optical absorption has been disregarded here because the distance of water through which the light passes is very short and the 8 optical absorption of water is much smaller than the energy loss at the interfaces. When light enters into a highly transparent substance such as water or plastic sheet, the ratio of unreflected energy penetrating the two interfaces is determined as follows.…”

“…[10]  These expressions are known as the Fresnel equations. [9] The amount of energy condensed on the receiver is calculated by combining these expressions and the light path deduced in the previous section.…”