Article

Simultaneous three-dimensional dynamic deformation measurements with pulsed digital holography

Institut für Technische Optik, Universität Stuttgart, Pfaffenwaldring 9, D-70569 Stuttgart, Germany.
Applied Optics (Impact Factor: 1.78). 01/2000; 38(34):7056-62. DOI: 10.1364/AO.38.007056
Source: PubMed

ABSTRACT

The three deformation components x, y, z of a vibrating object are measured simultaneously by use of digital holography with a double-pulse ruby laser source. The object is illuminated from three different directions, each optically path matched with three reference beams such that three independent digital holograms are formed and added incoherently in one single CCD image. The optical phase difference between the two recordings taken for each hologram is quantitatively evaluated by the Fourier-transform method so that a set of three phase maps is obtained, representing the deformation along three sensitivity vectors. The total object deformation is obtained as a vector resultant from the data of the three phase maps. To give the full three-dimensional (3-D) description, the shape of the object is measured by the two-wavelength contouring method. Experiments are performed with a cylinder as the test object, transiently and harmonically excited. The 3-D deformation and shape measurement results are presented graphically.

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    • "The reference beams provide spatial carrier frequency on the CCD to enable the capabilities of singleframe phase extraction [6]. The total intensity recorded on the CCD detector, I(x, y), due to incoherent superposition of three pairs of reference-object beams [7] can be shown by "
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    ABSTRACT: Holographic interferometric methods for measuring 3D displacement fields require at least three individual sensitivity vectors. Methods based on multiple directions of illumination have limited application when studying transient phenomena, including, but not limited to, measurements of biological tissues that have temporally-varying responses, such as the eardrum or Tympanic Membrane (TM). Therefore, to measure 3D displacements in such applications, all the measurements have to be done concomitantly. In this paper, we propose a new multiple illumination direction approach to measure 3D displacements from a single-shot hologram that contains displacement information from three sensitivity vectors. In our approach, the hologram of an object of interest is recorded with three simultaneous incoherently-superimposed pairs of reference and object beams, such that the modulation image corresponding to each illumination direction is reconstructed at a particular position on the image. Incoherent superposition of the beams is implemented by using three different laser diodes. Because of the differences in the position of each reference beam and wavelength of each pair of beams, the reconstruction distance and magnification of each sensitivity vector are different. We, therefore, developed and implemented a registration algorithm to accurately translate individual views into a single global coordinate system. Representative results will include measurements of shape and sound-induced 3D displacements of the TM.
    Full-text · Conference Paper · Jun 2014
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    • "The reference beams provide spatial carrier frequency on the CCD to enable the capabilities of singleframe phase extraction [6]. The total intensity recorded on the CCD detector, I(x, y), due to incoherent superposition of three pairs of reference-object beams [7] can be shown by "
    [Show abstract] [Hide abstract]
    ABSTRACT: Holographic interferometric methods for measuring 3D displacement fields require at least three individual sensitivity vectors. Methods based on multiple directions of illumination have limited application when studying transient phenomena, including, but not limited to, measurements of biological tissues that have temporally-varying responses, such as the eardrum or Tympanic Membrane (TM). Therefore, to measure 3D displacements in such applications, all the measurements have to be done concomitantly. In this paper, we propose a new multiple illumination direction approach to measure 3D displacements from a single-shot hologram that contains displacement information from three sensitivity vectors. In our approach, the hologram of an object of interest is recorded with three simultaneous incoherently-superimposed pairs of reference and object beams, such that the modulation image corresponding to each illumination direction is reconstructed at a particular position on the image. Incoherent superposition of the beams is implemented by using three different laser diodes. Because of the differences in the position of each reference beam and wavelength of each pair of beams, the reconstruction distance and magnification of each sensitivity vector are different. We, therefore, developed and implemented a registration algorithm to accurately translate individual views into a single global coordinate system. Representative results will include measurements of shape and sound-induced 3D displacements of the TM.
    Full-text · Conference Paper · Jun 2014
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    • "Multidimensional deformation measurement is carried out, thanks to a multidirectional spatial carrier [9] [10]. Demonstration was performed with simultaneous two-[9] and three-[10] dimensional measurements. Two-or three-noncoplanar sensitivity vectors are necessary. "
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    ABSTRACT: This paper presents the experimental optical analysis of the crack inside an electronic component. The optical setup is used to carry out multidimensional deformation measurements using digital color holography and the spatial multiplexing of holograms. Since the Fresnel transform method depends on wavelength, a wavelength-dependent-zero-padding algorithm is described and results in a rigorous sizing of each reconstructed monochrome image. The criterion to optimize the parameters is presented and is based on minimizing the widening of the impulse response of the full recording/reconstruction process. The application of the proposed method is illustrated through the analysis of the mechanical deformation of the electronic component, and offers keys to understand its failure mode in industrial conditions.
    Full-text · Article · Nov 2011 · Optics and Lasers in Engineering
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