Method for reducing sidelobes of limited diffracton pulse-echo images
First Claim
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1. A method for performing a pulse-echo sequence with a transducer that produces a limited diffraction beam, the steps comprising:
- transmitting a limited diffraction beam along a propagation axis through a propagation medium with a transmit aperture that produces an intensity which is maximum in a focal region around the propagation axis, and having sidelobes disposed radially outward from the focal region which are of less intensity than the focal region and which vary substantially in intensity as a function of angle around the propagation axis;
receiving an echo signal propagating in the medium along the propagation axis with a limited diffraction receive aperture that is highly receptive to the echo signal in the focal region around the propagation axis, and which is less receptive to echo signals in sidelobes disposed radially outward from the focal region and varying substantially in intensity as a function of angle around the propagation axis; and
wherein the transmit aperture and the receive aperture are oriented about the propagation axis such that there is minimum overlap of their respective sidelobes.
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Abstract
An acoustic transducer produces a limited diffraction beam during the transmit portion of a pulse-echo sequence that has sidelobes extending away from the beam axis in defined sectors. During the receive portion of the pulse-echo sequence a receive aperture for a limited diffraction beam is employed having sidelobes extending away from the beam axis in defined sectors that do not overlap the transmit sidelobes. Both limited diffraction Bessel beams and limited diffraction X waves are employed, and an acoustic transducer producing tenth derivative X waves is described.
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12 Claims
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1. A method for performing a pulse-echo sequence with a transducer that produces a limited diffraction beam, the steps comprising:
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transmitting a limited diffraction beam along a propagation axis through a propagation medium with a transmit aperture that produces an intensity which is maximum in a focal region around the propagation axis, and having sidelobes disposed radially outward from the focal region which are of less intensity than the focal region and which vary substantially in intensity as a function of angle around the propagation axis; receiving an echo signal propagating in the medium along the propagation axis with a limited diffraction receive aperture that is highly receptive to the echo signal in the focal region around the propagation axis, and which is less receptive to echo signals in sidelobes disposed radially outward from the focal region and varying substantially in intensity as a function of angle around the propagation axis; and wherein the transmit aperture and the receive aperture are oriented about the propagation axis such that there is minimum overlap of their respective sidelobes. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An ultrasound system for performing a pulse-echo sequence, the combination comprising:
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an ultrasonic transducer having an array of separate elements disposed on one of its surfaces; a transmitter for applying voltages to the separate transducer elements in accordance with a transmit aperture to produce a limited diffraction beam along a propagation axis in a sound medium during a transmit phase; a receiver connected to receive voltages produced by the separate transducer elements during an echo phase and combine them in accordance with a limited diffraction beam receive aperture; and wherein the limited diffraction beam produced by the transmit aperture and received by the receive aperture has a high intensity region focused around the propagation axis and sidelobes which extend radially outward therefrom and vary substantially in intensity as a function of angle around the propagation axis, the transmit aperture and receive aperture being oriented with respect to each other for minimum overlap of their sidelobes. - View Dependent Claims (11, 12)
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Specification