Real-Time Background Oriented Schlieren Using a Digitally Generated and Displayed Speckle Pattern

2022 ◽  
Author(s):  
Mark P. Wernet
Keyword(s):  
Real Time ◽  
Speckle Pattern ◽  
Background Oriented Schlieren

A Real-Time DSPI System for Measuring Surface Deformation in Clamped Bolted Joints

2008 ◽  
Author(s):  
Aidong Meng ◽  
Sayed A. Nassar
Keyword(s):  
Real Time ◽  
Vibration Isolation ◽  
Surface Deformation ◽  
Plane Surface ◽  
Speckle Pattern ◽  
The Real ◽  
Time Deformation ◽  
Out Of Plane ◽  
Phase Data ◽  
Set Up

A Digital Speckle Pattern Interferometry (DSPI) system is developed for the real-time measuring and monitoring the out-of-plane surface deformation around tightened threaded fasteners that are used to clamp bolted assemblies. Spatial phase shifting is employed to quantitatively determine the distribution of phase data by introducing a spatial carrier fringe pattern to the speckle interferogram. This is achieved by leading the object and reference beams to two separate apertures. The configuration is also suitable for collecting the real-time deformation during bolt tightening. The experimental DSPI system is set-up with optical components on a vibration-isolation table. A Matlab software is developed for the image acquisition and phase data calculation, which yields the out-of-plane surface deformation caused by the bolt preload. An aluminum joint is used with an M12 steel fastener. For miniature screw application, however, a plastic joint is used for collecting data.

Electronic Speckle Pattern Interferometry of the Vibrating Larynx

1995 ◽  
Vol 104 (1) ◽  
pp. 5-12 ◽  
Author(s):  
Glendon M. Gardner ◽  
Michelle Conerty ◽  
James Castracane ◽  
Steven M. Parnes
Keyword(s):  
Real Time ◽  
Quantitative Research ◽  
Speckle Pattern ◽  
Three Dimensional ◽  
Vocal Folds ◽  
Digital Data ◽  
Electronic Speckle Pattern Interferometry ◽  
Clinical Tool ◽  
Digital Hardware ◽  
Laser Holography

Laser holography is a technique that creates a three-dimensional image of a static object. This technique can be applied to the analysis of vibrating structures. Electronic speckle pattern interferometry uses a laser for illumination of the vibrating object and solid state detectors and digital hardware technology for capturing and processing the image in real time. This was performed on a human cadaver larynx and is the first time an interferogram of vibrating vocal cords has ever been obtained. Dark and bright interference fringes are seen that represent the vibratory motion of the vocal folds. These are presented in still photos as well as real-time on videotape. This method can provide advantages over current techniques of laryngeal study: it is sensitive to motion in the vertical dimension, and the digital data can be quantitatively analyzed. Application of this technique to study the larynx should eventually be a valuable clinical tool and provide quantitative research data.

Real-time comparative Digital Speckle Pattern Interferometry

1987 ◽  
Vol 64 (6) ◽  
pp. 501-506 ◽  
Author(s):  
A.R. Ganesan ◽  
C. Joenathan ◽  
R.S. Sirohi
Keyword(s):  
Real Time ◽  
Speckle Pattern ◽  
Digital Speckle Pattern Interferometry ◽  
Digital Speckle

A Study on the Vibration Characteristics of Symmetry and Asymmetry Laminated Composite Materials by Using ESPI

2007 ◽  
Vol 353-358 ◽  
pp. 2366-2370
Author(s):  
Kyung Min Hong ◽  
Young June Kang ◽  
Nak Kyu Park ◽  
Weon Jae Ryu
Keyword(s):  
Composite Materials ◽  
Real Time ◽  
Optical Measurement ◽  
Speckle Pattern ◽  
Laminated Composite ◽  
Vibration Characteristics ◽  
Electronic Speckle Pattern Interferometry ◽  
Full Field ◽  
Reinforced Plastics ◽  
Laminated Composite Materials

The ESPI (Electronic Speckle Pattern Interferometry) is a real-time, full-field, non-destructive optical measurement technique. In this study, ESPI was proposed for the purpose of vibration analysis for new and composite materials. Composite materials have various complicated characteristics according to the materials, orientations, stacking sequences of the ply and boundary conditions. Therefore, it was difficult to analyze composite materials. For efficient use of composite materials in engineering applications the dynamic behavior (i.e., natural frequencies and nodal patterns) should be informed. With the use of Time-Average ESPI, one could analyze vibration characteristics of composite material by real time easily. We manufactured two kinds of laminated composites (i.e., symmetry and asymmetry) which were consisted of CFRP (Carbon Fiber Reinforced Plastics) and the shape of the test piece was of rectangular form.

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