Are you asking about mechanical design of such a robot or vision problem? Mechanically, simple employing inward-facing gripper wheels (say, silicone rubber) should do the trick. If you want to use chameleon-like manipulators that's more tougher. 

If you're manually controlling the robot you don't really need computer vision, just a video stream. 

Dear Sri Vadana,

you might find this publication of interest:

https://www.researchgate.net/publication/233508332_Cost-Effective_Autonomous_Robots_for_Ballast_Water_Tank_Inspection

Cheers,

Jochen

Article Cost-Effective Autonomous Robots for Ballast Water Tank Inspection

One of my professor's colleague (Edward Grant), in 2000s had this pipe-crawling robot:

http://www.zoominfo.com/p/Edward-Grant/10177762

There might be a way to use similar approach to hold the pipe from outside, rather than inside