OPTRA HAS RECENTLY DEVELOPED AN OPTICAL TECHNIQUE, INVOLVINGTHE USE OF A 2-FREQUENCY HENE LASER, FOR MAKING PRECISE NON-CONTACT MEASUREMENTS OF THE TRANSVERSE MOTIONS OF DIFFUSE SURFACES.

OPTRA HAS RECENTLY DEVELOPED AN OPTICAL TECHNIQUE, INVOLVINGTHE USE OF A 2-FREQUENCY HENE LASER, FOR MAKING PRECISE NON-CONTACT MEASUREMENTS OF THE TRANSVERSE MOTIONS OF DIFFUSE SURFACES. OPTRA PROPOSES HEREIN TO APPLY THIS TECHNIQUE TO THE MEASUREMENT OF THE EXTENSION, UNDER APPLIEDLOAD, OF SAMPLES AT HIGH TEMPERATURES. THE PROPOSED TECHNIQUE IS PARTICULARLY ATTRACTIVE BECAUSE (1) IT REQUIRESNO CONTACT WHATSOEVER WITH THE SPECIMEN, (2) IT IS INSENSITIVE TO THE RADIATION EMITTED BY INCANDESCENT SURFACES, AND (3) IT PROVIDES FOR A PRACTICAL WORKING DISTANCE (THE SEPARATION BETWEEN THE SPECIMEN AND THE MEASUREMENT HEAD). THE PROPOSED MEASUREMENT SYSTEM CONSISTSOF A 2-FREQUENCY HENE LASER, AND ELECTRONIC PHASEMETER, AN EXTENSOMETER MEASUREMENT HEAD, AND A PC FOR DATA HANDLING AND OUTPUT FORMATTING.