Abstract :
Applications of active and passive devices employing the characteristics of sound to obtain results have been known to investigators for many years. However, in addition to these sonar or pulse-echo methods of analysis, there exist a variety of techniques in which a sound image is obtained in a way more analogous to optics. This analogy has, in the last few years, been extended to include holographic techniques, and has led to the inception of a new discipline¿acoustic holography. In this article, we trace the development of this new field as it originated from a fusion between ``conventional´´ acoustic imaging and optical holography; and we see how, in the few years of its existence, it has already generated its own unique methods and problems.
