Structural Holography
Résumé
The objective is to reconstruct the displacement or velocity field on a plate-like structure by only measuring
the displacement on a few lines (1 to 4). Thanks to 1D Fourier transform and to propagation operators
the displacement is reconstructed back and forth from the hologram positions. The structural holography
is a source separation technique and can be used to decompose the reconstructed field into incoming and
outcoming waves. Compared to the acoustic operator, fourth-order differential equation of the Kirchhoff
theory produces some waves purely evanescent whatever the wavenumber. Two versions of the structural
holography are thus defined: a near field structural holography (NSH) and a far field structural holography
(FSH) for which the purely evanescent waves are not taken into account. The structural holography theory
will be illustrated on the ideal case of an infinite plate. Then, an experimental validation of this method will
be shown and discussed.