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Underwater vision is the ability to see objects underwater, and this is significantly affected by several factors. Underwater, objects are less visible because of lower levels of natural illumination caused by rapid attenuation of light with distance passed through the water.
Ocean color is the branch of ocean optics that specifically studies the color of the water and information that can be gained from looking at variations in color. The color of the ocean , while mainly blue, actually varies from blue to green or even yellow, brown or red in some cases. [ 1 ]
How light acts in water is critical to how ecosystems function underwater. Knowledge of ocean optics is needed in aquatic remote sensing research in order to understand what information can be extracted from the color of the water as it appears from satellite sensors in space. The color of the water as seen by satellites is known as ocean color ...
The eyes are positioned on the top of the head, and the fish floats at the water surface with only the lower half of each eye underwater. The two halves are divided by a band of tissue and the eye has two pupils, connected by part of the iris. The upper half of the eye is adapted for vision in air, the lower half for vision in water. [35]
Secchi depth is the depth at which a disk is no longer visible to the human eye. This measurement was created in 1865 and represents one of the oldest oceanographic methods. [ 23 ] [ 24 ] To measure Secchi depth, a white or black-and-white disk is mounted on a pole or line and lowered slowly down in the water.
Water attenuates light by absorption, so use of a dive light will improve a diver's underwater vision at depth. [1] As the depth increases, more light is absorbed by the water. Color absorption depends on the purity of the water - pure water is most transparent to blue frequencies, but impurities may reduce this significantly.
Visual perception is the ability to interpret the surrounding environment through photopic vision (daytime vision), color vision, scotopic vision (night vision), and mesopic vision (twilight vision), using light in the visible spectrum reflected by objects in the environment.
On average, the system reduced the distance at which a ship could be seen from a surfaced submarine by 25% using binoculars, or by 33% using the naked eye. The camouflage worked best on clear moonless nights: on such a night in January 1942, HMS Largs was not seen until it closed to 2,250 yards (2,060 m) when counter-illuminated, but was ...