Karl A. Stetson
Karl Stetson Assoc., 2060 South St., Coventry, CT 06238
Holographic vibration analysis has changed greatly since its discovery in 1964. Thirty years ago, holograms were recorded exclusively with photographic plates using lasers that emitted barely 1 mW of power. Many years ago, high-power lasers and high-speed photographic plates freed holography from the need to hold objects immobile for long exposure times. Now the development of electro-optic holography is freeing it from the use of photographic film. The use of electronic phase stepping, modern pipeline image processors, and solid-state TV cameras have resulted in compact holographic systems that not only display vibratory fringe patterns in real time, but also allow direct conversion of fringes into numerical data. This paper will outline the current state of this technology and how it can impact on the study of musical instruments.