Laser-Based Interferometric Techniques for the Study of Musical Instruments

Laser-based interferometry techniques for the study of musical instruments are discussed in this chapter. The presented work demonstrates the advantages that the laser-based optical techniques provide and is mainly focused on the capabilities of the Electronic Speckle Pattern Interferometry (ESPI). The mathematical description of the time-average ESPI, the reading of the contour lines and the overcoming of the limitations of amplitude and phase vibration are analyzed. Furthermore, four representative studies using the ESPI for a Cretan Lyra, a Bendir, a classical Guitar and the ancient Greek lyra Chelys, are presented and demonstrate the capabilities of the method.