Compact fiber optic electronic laser speckle pattern interferometer
First Claim
1. An electronic speckle-pattern interferometry system based upon an in-plane displacement sensitive optical configuration, comprising:
- a thermal stressing unit operative to provide a slight temperature differential between a localized region and a surrounding area of an object under inspection;
a source of coherent optical radiation directed toward the object;
an optical fiber configured to receive radiation from the source, including a fiber stretcher to implement a phase-stepping technique for quantitative fringe analysis;
means for receiving and combining an image of the object with the output of the fiber stretcher so as to generate a fringe pattern characteristic of flaw-induced anomalies; and
a display device upon which to view the fringe pattern.
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Accused Products
Abstract
Material defects and damage are detected and evaluated by stressing the material and looking for flaw-induced anomalies in a fringe pattern generated by the interference between two coherent laser beams and electronic image processing. In terms of apparatus, the system includes a sensor head and a head-mounted display (HMD) interfaced to a computer, power supply, and control electronics. In one embodiment, the sensor head contains a thermal stressing unit and an in-plane displacement sensitive ESPI arrangement which measures the in-plane displacement of the deformation induced by applying thermal stressing. In operation, a thermal stressing unit is integrated with the sensor head to provide a slight temperature difference between a localized region and surrounding areas, with the change in temperature being used to reveal the defects and damage through the interference between the two laser beams and electronic image processing.
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Citations
8 Claims
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1. An electronic speckle-pattern interferometry system based upon an in-plane displacement sensitive optical configuration, comprising:
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a thermal stressing unit operative to provide a slight temperature differential between a localized region and a surrounding area of an object under inspection; a source of coherent optical radiation directed toward the object; an optical fiber configured to receive radiation from the source, including a fiber stretcher to implement a phase-stepping technique for quantitative fringe analysis; means for receiving and combining an image of the object with the output of the fiber stretcher so as to generate a fringe pattern characteristic of flaw-induced anomalies; and a display device upon which to view the fringe pattern. - View Dependent Claims (2, 3, 4)
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5. A method of performing electronic speckle-pattern interferometry using an in-plane displacement sensitive optical configuration, comprising the steps of:
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thermally stressing a localized region of an object under inspection; directing a source of coherent optical radiation directed toward the object; receiving radiation from the source through a fiber stretcher to implement a phase-stepping technique for quantitative fringe analysis; receiving and combining an image of the object with the output of the fiber stretcher so as to generate a fringe pattern characteristic of flaw-induced anomalies; and displaying the fringe pattern. - View Dependent Claims (6, 7, 8)
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Specification