Underwater imaging equipment differs optically from television surveillance utilized on land

Underwater imaging equipment differs optically from television surveillance used on land in two ways:

(1) The attenuation of light is very large;

(2) Due to the existence of various turbidities in the water, the light scattering phenomenon is quite serious.

The above two points are the basic problems that affect the quality of TV images. In water, the attenuation of light varies with the nature of water and the difference between plankton and other suspended matter, and changes with the wavelength of light. To solve the first problem, If it is only a sign of light attenuation, it can be solved with an enhanced light source. However, the scattering of the second point of light increases with the intensity of the light. Taking a photo in an environment with a lot of suspended matter in the water is like a lot of fog on the ground. The attenuation of light with a long wavelength is very large. The sign is just the opposite of that in the atmosphere. In a normal atmosphere, the larger the λ, the smaller the attenuation. Therefore, in this case, the longer the wavelength of light, the farther it can reach. Infrared photography can be particularly useful for capturing very far away from light. Things, but infrared photography can not pass through fog or rain, because the red light in the water will be absorbed. Since the attenuation of light in water is greater than that in the atmosphere, especially the attenuation of light with long wavelengths, the problem of light source selection arises.