An Experimental Verification of a New Theory for the Interpretation of Holographic Interference Patterns Resulting from Static Surface Displacements
TL;DR: In this article, an experimental investigation of the general equations describing holographic fringe patterns is described, and the fringe patterns resulting from known surface displacements are observed from two positions and the measured fringe spacings are compared with those predicted theoretically.
Abstract: General equations describing holographic fringe patterns have been derived in an earlier publication. In this paper an experimental investigation of the equations is described. The fringe patterns resulting from known surface displacements are observed from two positions and the measured fringe spacings are compared with those predicted theoretically. Two forms of displacement are considered: (i) rigid-body translations, (ii) linear displacement gradients. Results indicate that experimental observations are in close agreement with those predicted theoretically. The observation of plane strain is demonstrated in order to give a practical example of a problem involving a combination of the displacement classes (i) and (ii).
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TL;DR: This review paper is an attempt to rationalize the field by classifying the many different interpretation schemes into four main techniques, and by offering guidelines for the choice of technique for different applications.
Abstract: Holographic interferometry is a very powerful technique for the measurement of small deformations and displacements of opaque solid objects. Unfortunately, the quantitative interpretation of the fringe patterns is somewhat involved, and the large number of papers published on this subject in the past 10 years has caused considerable confusion. This review paper is an attempt to rationalize the field by classifying the many different interpretation schemes into four main techniques, and by offering guidelines for the choice of technique for different applications.
55 citations
26 citations
TL;DR: In this paper, a line of complete localization is used to estimate the position of a deformed object in a double-exposed hologram, where the light waves reflected by the vicinity of this point have all the same phase shift.
Abstract: The interpretation of the fringe pattern formed by a double-exposed hologram of a deformed object leads first to the displacement of a point of the object surface. Further, if one desires to know the strains and the rotations at this point without numerical differentiation, the concept of the line of complete localization may be used. Associated to each point of the surface there is a locus in space where the light waves reflected by the vicinity of this point have all the same phase shift. Points of this curve may be determined by a criterion concerning the direction of the fringes and by use of a special device based upon it. Linear equations yield then directly and in general cases the sought strains and rotations. Some experimental results are given which attempt to show the applicability of this method. Further developments should permit the investigation of the constitutive equation of any non-transparent body.
21 citations
01 Jan 1978
20 citations
01 Jan 1979
TL;DR: The kinematics of the deformation of a body and the formation of holographic images will be combined, to explain how holography can be used to measure deformations.
Abstract: Up to now, we have investigated, on the one hand, the kinematics of the deformation of a body (Sect. 2.2) and, on the other hand, the formation of holographic images (Chap. 3). In this chapter, these two subjects will be combined, because we are going to explain how holography can be used to measure deformations.
18 citations
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TL;DR: In this article, the distribution of intensity in the resultant pattern depends on the relative phases of the component patterns, and by measuring the correlation between the resultant patterns at two different times a change of relative phase is detected.
Abstract: When a surface is illuminated with laser light it has a speckled appearance due to random interference. If two speckle patterns are superimposed the distribution of intensity in the resultant pattern depends on the relative phases of the component patterns. By measuring the correlation between the resultant patterns at two different times a change of relative phase is detected. This leads to a versatile method of measuring either the normal or in-plane components of displacement over the whole of a surface at one time.
485 citations
TL;DR: In this paper, it is established that live holographic interference patterns are the result of the interference occurring between the wavefronts diffracted from corresponding points in the reconstructed image and the displaced real object.
Abstract: It is re-established, in a suitable form, that live holographic interference patterns are the result of the interference occurring between the wavefronts diffracted from corresponding points in the reconstructed image and the displaced real object. This result is employed to determine the path difference equations for the wavefront forming the interference pattern as observed in three orthogonal directions. A set of linear equations is derived which is shown to relate the components of a small general surface displacement to the fringe spacing and localization plane of the observed interference pattern. The practical application of the theory is then discussed. Numerical equations are derived for various geometries of interferometer and in particular the measurements of rigid-body translations and plane strain are dealt with. In addition it is shown how problems that arise in the measurement of complicated surface displacements may be considerably simplified.
23 citations