Broadband time domain acoustic holography based on the discrete orthonormal S-transform

The purpose of this paper is to deal with the problem of nonstationary broadband sound fields more efficiently. A basis function of the discrete orthonormal S-transform (DOST) is used to analyze the measured signal. With respect to the time domain signal in a certain band, DOST leads to a representation centered at a specific frequency with a certain bandwidth in the time domain directly, instead of a series of frequency lines after Fourier transform. It is shown theoretically that the DOST can be introduced into time domain acoustic holography (TDAH) and in this way a new broadband TDAH (BTDAH) is developed. Compared to the conventional method based on short-time Fourier transform (STFT), the BTDAH can, potentially, give access to nonstationary broadband sound source reconstruction techniques, with the need for relatively fewer data to store and process. Additionally, for the example studied here, the newly proposed method provides a favorable source reconstruction over the time, space and frequency band domains.