An improved moving frame acoustic holography for coherent bandlimited noise

Abstract

The moving frame acoustic holography method, which can increase the aperture size and spatial resolution of a hologram was recently proposed [H. S. Kwon and Y.-H. Kim, J. Acoust. Sec. Am. 103, 1734-1742 (1998)]. This method continuously sweeps a stationary sound field by using a line array of microphones so that the hologram of a scanned plane can be obtained. This method enables us to visualize the noise generated by moving noise sources based on near-field acoustic holography. However, a drawback is that it can be applied only to sinusoidal components. This limits its practical application. In practice, bandlimited and transient noise, as well as a sinusoidal component, must be dealt with in order to effectively control the noise generated by the moving noise sources. This paper addresses a way to improve the moving frame acoustic holography method so that it can be applied not only to sinusoidal components, but also to a coherent bandlimited noise. The practical applicability of the improved method is also verified by experiments. (C) 1998 Acoustical Society ofAmerica. [S0001-4966(98)04111-3].