How to produce images with sound has intrigued engineers and scientists for many years. Bats, whales and dolphins can easily get good mental images with acoustical energy, but humans have little natural ability for obtaining such images. The history of engineering and science, however, is an impressive demonstration that technological solutions can compensate, and then some, for deficiencies of nature in humans. Thus with the proper technology, we too can "see" with sound. Many methods involv ing ultrasonic energy can be employed to enable us to do so. Few of these methods are at all reminiscent of the acoustic systems employed by animals. Pulse-echo, phase-amplitude and amplitude-mapping approaches constitute the conceptual bases for three fundamentally different types of acoustic imaging systems and can be used for categorizing the systems. However, by now systems exist that combine the approaches in such sophisticated ways as to make an unambiguous categorization of some of the more complicated systems difficult or impossible. Among the instruments so far pro duced are mechanically-scanning focused instruments, chirped pulse-echo instruments, and instruments involving holography, tomography, parametric excitation, phase conju gation, neural networks, random phase transduction, finite element methods, Doppler frequency shifting, pseudo inversion, Bragg diffraction and reflection, and a host of other principles. The fifty-five chapters in this volume are selected from papers presented at the Eighteenth International Symposium on Acoustical Imaging which was held in Santa Barbara, California on September 18 - 20, 1989.
The International Symposium on Acoustical Imaging is a unique forum for advanced research, covering new technologies, developments, methods and theories in all areas of acoustics. This interdisciplinary Symposium has been taking place every two years since 1968. In the course of the years the proceedings volumes in the Acoustical Imaging Series have become a reference for cutting-edge research in the field. In 2009 the 30th International Symposium on Acoustical Imaging was held in Monterey, CA, USA, March 1-4. Offering both a broad perspective on the state-of-the-art as well as in-depth research contributions by the specialists in the field, this Volume 30 in the Series contains an excellent collection of forty three papers presented in five major categories:
Biomedical Imaging
Acoustic Microscopy
Non-Destructive Evaluation
Systems Analysis
Signal Analysis and Image Processing
Audience
Researchers in medical imaging and biomedical instrumentation experts.
