The use of ultrasonic transducers for process tomography is in its infancy relative to many other techniques, in particular considering the widespread use of ultrasonic transducers in a variety of non-tomographic sensing applications. This review deals with the background sensing principles of ultrasound transducers employed in tomography, their associated advantages and their difficulties, including the critical time required for data collection, and implications for multiple projection tomography. The theoretical and basic practical implementation of tomography systems using ultrasonic transducers is then considered. Finally a review is included of research investigations into the use of ultrasonic-based process tomography systems.
