Choice of underwater cameras, lenses and signaling methods

1. The refraction of water and the choice of the optical system

 Because the refraction of water is greater than that of the atmosphere, the viewing angle of the underwater tv camera is a quarter narrower in the water than in the atmosphere. For three-quarters of the atmosphere. In order to inspect the subject in a wider range, the camera of the underwater TV must choose a wide-angle lens. In addition, the lens requires the highest possible transmittance.

2. Agility and camera selection

 Due to the lack of brightness in the water, it is possible to compensate with artificial lighting. However, it is also very important to improve the agility of the camera itself, so it is necessary to consider the choice of camera.

 In the past, light-conducting camera tubes that are adapted to light weight are usually used. But it falls short in image retention and agility. Now more CCD cameras are used, which are widely used because of their small size, lightweight, low power consumption, good reliability, no signs of burns, anti-vibration, and corresponding wide spectrum. And because of the variety, you can also choose a high-sensitivity CCD camera.

3. Consideration of video signal reporting methods

The maneuverability of underwater TV cameras is much worse than on land, so the transmission of video signals requires many considerations. The transmission of image signals usually uses coaxial cables. The bandwidth of the image signals of TV cameras is usually from DC to several megahertz. When used at depths of several kilometers, the high-frequency level of the signal sent by the camera must be increased. The high-frequency compensation method is also adopted at the absorption end. No matter how deep the depth is, consider using frequency modulation or pulse code modulation to prevent signal deterioration during transmission.