Communications – electrical: acoustic wave systems and devices – Acoustic image conversion
Patent
1996-06-03
1998-09-15
Pihulic, Daniel T.
Communications, electrical: acoustic wave systems and devices
Acoustic image conversion
342179, G03B 4206
Patent
active
058089624
ABSTRACT:
An ultrasound or electromagnetic imaging system characterized by a two-dimensional phased array of ultrawideband, ultrasparse transducers. Ultrasparse is defined as an average inter-transducer spacing' which is greater than a .lambda./2 Nyquist spacing for the transducers and which is greater than a pulse length cT, where c is the speed of propagation of a pulse from a transducer in the imaging medium and T is a duration of the pulse. An ultrawideband low Q transient pulse is emitted by each of the transducers during a transmit mode, and the resulting ultrasound image signals are received from the transducers during a receive mode, processed, and displayed. Preferably, the transducers are uniformly weighted and excited and periodically spaced by distance and/or angle within the coordinate system of the two-dimensional phased array such that projections of the transducers onto a coordinate axis of the coordinate system minimally overlap. The resulting image signals have an average side radiation level which approaches 1/N, which is substantially lower than if the same number of array elements were employed with randomly chosen spacings. The transducers may be arranged in a grid or a spiral or any other pattern such that the projections of each of the transducers to respective axes of the coordinate system minimally overlap each other. In other words, the transducers are periodically spaced and do not shadow each other.
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Schwartz Jodi L.
Steinberg Bernard D.
Pihulic Daniel T.
The Trustees of the University of Pennsylvania
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