Underwater visual inspection room is an important method of underwater observation. It is intuitive and simple, and can make permanent records. Visual measurement methods include diver's detection and measurement, still water camera, remote control TV box dynamic camera and so on.

Visual inspection can only be performed in the core or shallow offshore waters. Deep water inspection in deep sea area is completed by deep and shallow observation boat and remote control television.

If the diver has long-term deep potential underwater inspection, besides the diver should have skilled diving skills, and should make a reliable guarantee for its safety.

Regardless of the purpose and means of underwater inspection, in order to clearly reflect the target and make corresponding records, the following points should be done:

First, clean the surface of the target;

(2) Establish a reference coordinate system in order to clarify the relative relationship between the location, elevation and coordinates of the inspection area;

(3) When the water depth is below 5-6m, the necessary lighting should be equipped.