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High-speed 3D imaging system using coded wavefront generated by Walsh function modulated signals

An experimental ultrasonic three dimensional (3D) imaging system for high-speed data acquisition has been developed. A 3D image can be reconstructed for each transmission of pulses modulated by Walsh functions. Matrix transducers of 40/spl times/40 2 MHz elements and a data acquisition system have been developed to evaluate the system performance. In this paper, we describe the principle, the fabrication process of the 2D array, and the data acquisition system. Three dimensional images of 20 dB dynamic ranges were successfully obtained for standard ultrasonic phantoms with 32 transmissions using the developed system.