[2] ZHANG W W, ZHUANG B H. Non-contact laser inspection for the inner wall surface of a pipe [J]. Meas. Sci. Technol, 1998, (9): 1380-1387.
[3] Mamoru MIZUNUMA, Shigeki OGAWA , Hiroki KUWANO. Deformation detection on the pipe inner wall using a laser-beam scanning displacement sensor [J]. SPIE, 1993, 2066:98-105.