Broadband acoustic holography reconstruction from acoustic intensity measurements. I: Principle of the method

A method, broadband acoustic holography from intensity measurements (BAHIM), is developed for the reconstruction of sources using nearfield acoustic intensity measurement. Nearfield acoustic holography (NAH) is used, but data concerning complex pressure on the hologram are not acquired directly. These data are obtained by processing measurements of active intensity and potential energy density (quadratic pressure). These quadratic values are measured independently at each point on the hologram and therefore do not require a phase reference signal corresponding to the source. This method is thus applicable to sources emitting a broadband spectrum and, more generally, to industrial sources, for which the excitation is not known. The principle of the method is described and the advantages of this type of processing are illustrated by examples.