I recently performed an internal meter tube inspection using a tractor type system. It was great in allowing us to view the whole meter tube, all 20+ meters of it. As the tube was a single piece, we couldn’t take it apart and touch or visually inspect the inner surface with the naked eye.
Or naked eyes, as it were. Stereoscopic vision allows us to get a feeling of depth, assuming we can’t touch an object. From the images transmitted back to us by the tractor, it was unclear whether a blemish was a pit, a bubble or a surface mark. We were limited in the ability to view a spot at different angles, which would give us a better three dimensional feel.
This leads on to my question, why doesn’t someone invent a stereoscopic remote inspection system? It’s an old idea. It’s been done on a large scale (doesn’t get bigger than the sun), small scale (microscopes), so why not at a scale that is useful to us operational grunts?
Wata - Malaysian Oil and Gas Engineer 
Jabba know a friend who’s a protologist. I think it saves him doing his job using a finger.
Sorry, it should be spelt as proctologist.
Anyway, its time for my checkup….. without the machine with wheels and a spotlight doing the remote expedition… (oops, it should be remote inspection).