Method for detecting two-dimensional flow for ultrasound color flow imaging
First Claim
1. A method for determining the velocity of a flowing material using an array of ultrasonic transducers, comprising the steps of:
- (a) activating each of a first plurality of ultrasonic transducers of said array to transmit an ultrasonic beam of a predetermined frequency, said first plurality of ultrasonic transducers forming a transmission aperture, each transducer of said transmission aperture being activated at times such that said transmitted ultrasonic beam is directed along a first vector from a center of said transmission aperture through a first point of interest located at a first range and a second point of interest located at a second range;
(b) steering and focussing a second plurality of ultrasonic transducers of said array forming a first reception aperture to detect a first backscattered ultrasonic beam directed along a first line of sight from said first point of interest to a center of said first reception aperture, said first backscattered ultrasonic beam being formed when said transmitted ultrasonic beam arrives at said first point of interest;
(c) steering and focussing a third plurality of ultrasonic transducers of said array forming a second reception aperture to detect a second backscattered ultrasonic beam directed along a second line of sight from said first point of interest to a center of said second reception aperture, said second backscattered ultrasonic beam being formed when said transmitted ultrasonic beam arrives at said first point of interest;
(d) steering and focussing said second plurality of ultrasonic transducers of said first reception aperture to detect a third backscattered ultrasonic beam directed along a third line of sight from said second point of interest to said center of said first reception aperture, said third backscattered ultrasonic beam being formed when said transmitted ultrasonic beam arrives at said second point of interest;
(e) steering and focussing said third plurality of ultrasonic transducers of said second reception aperture to detect a fourth backscattered ultrasonic beam directed along a fourth line of sight from said second point of interest to said center of said second reception aperture, said fourth backscattered ultrasonic beam being formed when said transmitted ultrasonic beam arrives at said second point of interest; and
(f) determining first through fourth Doppler shifts in the frequencies of said first through fourth backscattered ultrasonic beams, respectively.
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Accused Products
Abstract
A triangulation method and apparatus for measuring the velocity of a flowing material at a point of interest along two lines of sight which have different vector components. The flow velocity along two different image vectors is measured simultaneously by separately processing the signals from left and right reception apertures (14, 16). In one case, the positions of the reception apertures are held constant and conventional dynamic focussing on receive is used to steer the apertures to follow the transmitted energy as a function of range depth. In an alternative case, the transducers included in each reception aperture are dynamically reassigned in order to maintain a fixed triangulation angle. In this case a reception aperture shifts away from the transmission aperture (12) to track the received backscattered ultrasonic energy at a constant triangulation angle.
55 Citations
23 Claims
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1. A method for determining the velocity of a flowing material using an array of ultrasonic transducers, comprising the steps of:
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(a) activating each of a first plurality of ultrasonic transducers of said array to transmit an ultrasonic beam of a predetermined frequency, said first plurality of ultrasonic transducers forming a transmission aperture, each transducer of said transmission aperture being activated at times such that said transmitted ultrasonic beam is directed along a first vector from a center of said transmission aperture through a first point of interest located at a first range and a second point of interest located at a second range; (b) steering and focussing a second plurality of ultrasonic transducers of said array forming a first reception aperture to detect a first backscattered ultrasonic beam directed along a first line of sight from said first point of interest to a center of said first reception aperture, said first backscattered ultrasonic beam being formed when said transmitted ultrasonic beam arrives at said first point of interest; (c) steering and focussing a third plurality of ultrasonic transducers of said array forming a second reception aperture to detect a second backscattered ultrasonic beam directed along a second line of sight from said first point of interest to a center of said second reception aperture, said second backscattered ultrasonic beam being formed when said transmitted ultrasonic beam arrives at said first point of interest; (d) steering and focussing said second plurality of ultrasonic transducers of said first reception aperture to detect a third backscattered ultrasonic beam directed along a third line of sight from said second point of interest to said center of said first reception aperture, said third backscattered ultrasonic beam being formed when said transmitted ultrasonic beam arrives at said second point of interest; (e) steering and focussing said third plurality of ultrasonic transducers of said second reception aperture to detect a fourth backscattered ultrasonic beam directed along a fourth line of sight from said second point of interest to said center of said second reception aperture, said fourth backscattered ultrasonic beam being formed when said transmitted ultrasonic beam arrives at said second point of interest; and (f) determining first through fourth Doppler shifts in the frequencies of said first through fourth backscattered ultrasonic beams, respectively. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for determining the velocity of a flowing material at a plurality of points located at different ranges along a first vector using a linear array of ultrasonic transducers, comprising the steps of:
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(a) activating each of a first plurality of ultrasonic transducers of said array to transmit an ultrasonic beam of a predetermined frequency, said first plurality of ultrasonic transducers forming a transmission aperture, each transducer of said transmission aperture being activated at times such that said transmitted ultrasonic beam is directed along said first vector from a center of said transmission aperture through each of said plurality of points; (b) steering and focussing a second plurality of ultrasonic transducers of said array forming a first reception aperture to detect respective backscattered ultrasonic beams directed along respective lines of sight from respective ones of said plurality of points to a center of said first reception aperture, said backscattered ultrasonic beams being respectively formed when said transmitted ultrasonic beam arrives at said respective points along said first vector; (c) steering and focussing a third plurality of ultrasonic transducers of said array forming a second reception aperture to detect respective backscattered ultrasonic beams directed along respective lines of sight from respective ones of said plurality of points to a center of said second reception aperture, said backscattered ultrasonic beams being respectively formed when said transmitted ultrasonic beam arrives at said respective points along said first vector; (d) for each of said points, determining a first Doppler shift in the frequency of the backscattered ultrasonic beam backscattered from each respective point to said first reception aperture; and (e) for each of said points, determining a second Doppler shift in the frequency of the backscattered ultrasonic beam backscattered from each respective point to said second reception aperture. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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16. An ultrasound color flow imaging system for determining the velocity of a flowing material at a plurality of points of interest along a vector, comprising:
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(a) an array of ultrasonic transducers; (b) means for activating each of a first plurality of ultrasonic transducers of said array to transmit an ultrasonic beam of a predetermined frequency, said first plurality of ultrasonic transducers forming a transmission aperture, each transducer of said transmission aperture being activated at times such that said transmitted ultrasonic beam is directed along said first vector from a center of said transmission aperture through each of said plurality of points; (c) means for steering and focussing a second plurality of ultrasonic transducers of said array forming a first reception aperture to detect respective backscattered ultrasonic beams directed along respective lines of sight from respective ones of said plurality of points to a center of said first reception aperture, said backscattered ultrasonic beams being respectively formed when said transmitted ultrasonic beam arrives at said respective points along said first vector; (d) means for steering and focussing a third plurality of ultrasonic transducers of said array forming a second reception aperture to detect respective backscattered ultrasonic beams directed along respective lines of sight from respective ones of said plurality of points to a center of said second reception aperture, said backscattered ultrasonic beams being respectively formed when said transmitted ultrasonic beam arrives at said respective points along said first vector; (e) means for determining a first Doppler shift in the frequency of the backscattered ultrasonic beam backscattered from each respective point to said first reception aperture and a second Doppler shift in the frequency of the backscattered ultrasonic beam backscattered from each respective point to said second reception aperture. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23)
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Specification