Acoustic Imaging of Sound Sources with a Student-Designed Acoustic Camera

An acoustic camera consists of a microphone array, a data recorder and sound analysis- and visualization software. It creates a color-coded sound map that displays the sound sources overlaid on the visual image of the recorded object. The sound maps are usually produced by analyzing the phase differences of the signals measured by the array microphones. Delay-andsum beamformer and multiple signal classification (MUSIC) techniques are used in this work for the localization of sound sources. Beamformers are able to determine the amplitude of incident sound, but suffer from poor resolution and from ghost images. MUSIC, on the other hand, is an established technique for efficient and accurate noise source location, which can provide highresolution source maps, but does not provide any information about the sound level. The combination of both methods gives comprehensive information about the acoustic emission of the system under investigation.