Detection of mesa spots and indents on slowly moving object surface by laser-light beam scanning

Abstract

Measuring time of mesa spots and indents on a slowly moving (less than 8 mm/s) is greatly reduced to 3.5 seconds (for 121 points) by utilizing a 3D range image measuring system. In the system, a laser light beam from a range-finding speedometer is mechanically scanned to illuminate a successive point on the object surface. The minimum detectable size of a square mesa or a square indent which is moving 2 times the minimum scanning length (MSL=7.6 mm), and the minimum detectable depth of those was 6 mm-7 mm.