公开(公告)号：WO1993020419A1

公开(公告)日：1993-10-14

申请号：PCT/GB1993000256

申请日：1993-02-08

Applicant: ROVER GROUP LIMITED

Inventor： ROVER GROUP LIMITED ,  STOCKLEY, Barrie, Carlton ,  BUCKBERRY, Clive, Henry

IPC: G01L01/24

CPC classification number: G01L1/241

Abstract: Polarized light from a polarizer (12) is passed through a stressed birefringent objet (14) and an analyser (16) to produce a fringe pattern representative of the stress in the object (14). The fringe pattern is observed with a CCD camera (18) and intensity information of the pattern is input to a computer (22). The process is repeated for at least two wavelengths of light and the information for the different wavelengths is combined to form a stress map of the object (14) for display on a VDU (24).