Investigation of the near field of a loudspeaker using tomographic reconstruction from TV-holography measurements

It has previously been shown that a three-dimensional mapping of an acoustic field's amplitude and phase may be calculated from a set of TV-holography measurements by use of tomographic techniques. In this paper a thorough mathematical description of this measuring technique is given. An increased number of measured projections improves the tomographic reconstructions significantly. Techniques for obtaining quantitative data for the pressure amplitude of the acoustic field are implemented. The technique is demonstrated by measurements of the near field of a loudspeaker and these measurements are shown to agree well with measurements obtained with a microphone. (C) 1998 Acoustical Society of America. [S0001-4966(98)02309-1]