Digital Double Exposure Holography by means of Polarization Optics

2007 ◽  
Author(s):  
Daniel Claus ◽  
Peter Bryanston-Cross ◽  
Brenda Timmerman
Keyword(s):  
Double Exposure ◽  
Polarization Optics ◽  
Exposure Holography

Holographic Evaluation of Edge Delamination in Bars Bonded to a Rigid Support With Foam-Adhesive

1996 ◽  
Vol 118 (3) ◽  
pp. 330-334 ◽  
Author(s):  
S. Qin ◽  
H. M. Shang ◽  
C. L. Giam ◽  
C. E. Tee
Keyword(s):  
Theoretical Analysis ◽  
Rapid Detection ◽  
Iterative Procedure ◽  
Point Load ◽  
Nonlinear Relationship ◽  
Rigid Support ◽  
Double Exposure ◽  
Simple Method ◽  
Exposure Holography ◽  
Edge Delamination

When a bar having one end bonded to a rigid support with foam-adhesive is loaded, the high peeling stresses at the bonded edge foster edge delamination along the interface of bonding. Upon inspection by double exposure holography, with an incremental point load applied at the free end of the bar between exposures, the indistinct fringe perturbation and the unknown resilience of the foam-adhesive (quantified by its foundation modulus) impede unambiguous evaluation of the condition of adhesion. This paper describes a simple method for rapid detection and assessment of artificially created edge delamination in such bar structures. The theoretical analysis elucidates the suitability of modelling the bar as partially clamped, and having an equivalent slope at its support related to the foundation modulus. Two dimensionless parameters are defined, which have between them a linear relationship for a nondelaminated bonding but a nonlinear relationship for a delaminated one. Finally, a simple iterative procedure is described for estimating the delaminated length without having to predetermine the elasticity of the support.

Automatic analysis of knee ligaments using double exposure holography

1991 ◽  
Vol 24 (6) ◽  
pp. 489
Author(s):  
Huang Zhi ◽  
Torsten Wredmark ◽  
Ulrik Willers ◽  
Ingegerd Dirtoft ◽  
Rolf B Johansson
Keyword(s):  
Automatic Analysis ◽  
Double Exposure ◽  
Knee Ligaments ◽  
Exposure Holography

Transient interference gratings and holograms in dyed plastic

1984 ◽  
Vol 62 (7) ◽  
pp. 669-673
Author(s):  
Sergio Calixto ◽  
R. A. Lessard
Keyword(s):  
Real Time ◽  
Diffraction Efficiency ◽  
Laser Light ◽  
Thick Layer ◽  
Double Exposure ◽  
Naked Eye ◽  
Sufficient Intensity ◽  
Exposure Holography ◽  
Reading Beam ◽  
Made In

Transient diffraction gratings were holographically made in dyed plastic by absorbing laser light. Mean energy values of 40 mJ/cm2 absorbed in a 3-mm thick layer were needed to make gratings that lasted about 10 s. The writing beams and a reading one of different wavelength were simultaneously made to fall on the plastic: the reading beam was diffracted by the grating, which produced transient diffracted beams of sufficient intensity to be seen by the naked eye or to be stored permanently by conventional photographic methods. Curves showing diffraction efficiency versus exposure with grating frequency as a parameter are presented. Applications to real-time single and double exposure holography are also discussed.

Holographic Inspection of Plates Containing Areas of Localized Thickness Variation

1994 ◽  
Vol 116 (2) ◽  
pp. 162-167 ◽  
Author(s):  
H. M. Shang ◽  
M. Lwin ◽  
T. E. Tay
Keyword(s):  
Visual Detection ◽  
Accurate Estimation ◽  
Thickness Variation ◽  
Uniform Pressure ◽  
Circular Plates ◽  
Double Exposure ◽  
Simple Method ◽  
Exposure Holography ◽  
Fringe Patterns

Circular plates, under unknown clamping conditions and containing simulated defects in the form of circular localized thinning or thickening, are inspected by double-exposure holography. With an incremental uniform pressure applied between exposures, eccentric defects are readily revealed from the distinct irregular fringe patterns. In the case of central circular defects, however, the absence of distinct irregular fringe patterns does not enable easy visual detection of the defects. The simple method of analysis described in this paper, based on the fact that the displacement in a defective plate differs from that in a defect-free plate, allows easy deduction of central and eccentric defects from the fringe patterns. Furthermore, this method enables identification of the type of defect (localized thinning or thickening), the extent of thickness variation, as well as an accurate estimation of the location and size of the defect.

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