Panoramic dual-directional shearography assisted by a bi-mirror

Area of Science:

• Optics and Photonics
• Materials Science
• Non-Destructive Testing

Background:

• Shearography is a powerful optical technique for non-destructive testing, but traditional systems often lack multi-directional deformation measurement capabilities.
• Simultaneous determination of out-of-plane deformation derivatives in multiple directions is crucial for thorough structural integrity assessment.

Purpose of the Study:

• To propose and demonstrate a panoramic dual-directional shearography system capable of simultaneous, global inspection of objects.
• To enhance the capabilities of shearography for detailed out-of-plane deformation analysis.

Main Methods:

• A novel shearography configuration utilizing a dichroic filter (DF), a 3CCD camera, and dual-wavelength light.
• Employing dual-wavelength illumination and corresponding imaging sensors for independent shearogram generation.
• Introducing an additional image-shearing capability by adjusting the tilted stereo-angle of the DF.
• Utilizing an auxiliary bi-mirror for complete object surface illumination and single-shot capture.

Main Results:

• The system successfully determines out-of-plane deformation derivatives in two directions simultaneously.
• Independent shearograms were generated using dual-wavelength light and a 3CCD camera.
• The adjusted DF provided a second, wavelength-dependent measurement with additional image-shearing.
• The auxiliary bi-mirror enabled full object illumination and single-shot imaging.

Conclusions:

• The proposed panoramic dual-directional shearography system is effective for global object inspection.
• The system offers enhanced capabilities for analyzing deformation in multiple directions.
• This advancement in shearography provides a more comprehensive approach to non-destructive testing and structural analysis.