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Title: Method and apparatus for measuring surface movement of an object using a polarizing interferometer

Abstract

A system for non-destructively measuring an object and controlling industrial processes in response to the measurement is disclosed in which an impulse laser generates a plurality of sound waves over timed increments in an object. A polarizing interferometer is used to measure surface movement of the object caused by the sound waves and sensed by phase shifts in the signal beam. A photon multiplier senses the phase shift and develops an electrical signal. A signal conditioning arrangement modifies the electrical signals to generate an average signal correlated to the sound waves which in turn is correlated to a physical or metallurgical property of the object, such as temperature, which property may then be used to control the process. External, random vibrations of the workpiece are utilized to develop discernible signals which can be sensed in the interferometer by only one photon multiplier. In addition the interferometer includes an arrangement for optimizing its sensitivity so that movement attributed to various waves can be detected in opaque objects. The interferometer also includes a mechanism for sensing objects with rough surfaces which produce speckle light patterns. Finally the interferometer per se, with the addition of a second photon multiplier is capable of accuratelymore » recording beam length distance differences with only one reading. 38 figs.« less

Inventors:
; ; ;
Publication Date:
Research Org.:
Surface Combustion Inc
OSTI Identifier:
46305
Patent Number(s):
US 5,414,510/A/
Application Number:
PAN: 8-194,032
Assignee:
Textron Defense Systems, Division of Avco Corporation, Wilmington, MA (United States) PTO; SCA: 320303; 420500; PA: EDB-95:077391; SN: 95001384497
DOE Contract Number:  
FC07-89ID12830
Resource Type:
Patent
Resource Relation:
Other Information: PBD: 9 May 1995
Country of Publication:
United States
Language:
English
Subject:
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION; 42 ENGINEERING NOT INCLUDED IN OTHER CATEGORIES; NONDESTRUCTIVE TESTING; MEASURING INSTRUMENTS; INDUSTRIAL PLANTS; PROCESS CONTROL; DESIGN; MOTION; PHOTOMULTIPLIERS; MECHANICAL VIBRATIONS; SIGNAL CONDITIONERS

Citation Formats

Schultz, T.J., Kotidis, P.A., Woodroffe, J.A., and Rostler, P.S. Method and apparatus for measuring surface movement of an object using a polarizing interferometer. United States: N. p., 1995. Web.
Schultz, T.J., Kotidis, P.A., Woodroffe, J.A., & Rostler, P.S. Method and apparatus for measuring surface movement of an object using a polarizing interferometer. United States.
Schultz, T.J., Kotidis, P.A., Woodroffe, J.A., and Rostler, P.S. Tue . "Method and apparatus for measuring surface movement of an object using a polarizing interferometer". United States.
@article{osti_46305,
title = {Method and apparatus for measuring surface movement of an object using a polarizing interferometer},
author = {Schultz, T.J. and Kotidis, P.A. and Woodroffe, J.A. and Rostler, P.S.},
abstractNote = {A system for non-destructively measuring an object and controlling industrial processes in response to the measurement is disclosed in which an impulse laser generates a plurality of sound waves over timed increments in an object. A polarizing interferometer is used to measure surface movement of the object caused by the sound waves and sensed by phase shifts in the signal beam. A photon multiplier senses the phase shift and develops an electrical signal. A signal conditioning arrangement modifies the electrical signals to generate an average signal correlated to the sound waves which in turn is correlated to a physical or metallurgical property of the object, such as temperature, which property may then be used to control the process. External, random vibrations of the workpiece are utilized to develop discernible signals which can be sensed in the interferometer by only one photon multiplier. In addition the interferometer includes an arrangement for optimizing its sensitivity so that movement attributed to various waves can be detected in opaque objects. The interferometer also includes a mechanism for sensing objects with rough surfaces which produce speckle light patterns. Finally the interferometer per se, with the addition of a second photon multiplier is capable of accurately recording beam length distance differences with only one reading. 38 figs.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1995},
month = {5}
}