Beamforming apparatus and method for ultrasonic imaging systems
First Claim
1. A method for steering and focusing the received beam of an array of ultrasonic transducers to an incremental portion of an object, each transducer being adapted to provide a received signal representing returns of ultrasonic energy from object points of the object, said method comprising the steps of:
- providing a plurality of first reference signals, each first reference signal being associated with one of the received signals and having a frequency and phase that are matched to the frequency and phase of those components in the associated received signal that represent returns from object points within said incremental portion;
multiplying each received signal by its associated first reference signal so as to develop a plurality of first product signals each related to the product of a received signal and its associated first reference signal;
integrating each of said plurality of first product signals during an associated one of a plurality of resolution windows, the time occurrence of each said resolution window being substantially equal to the time occurrence of those components in the received signal, from which the associated said first product signal has been developed, that represent returns from object points within said incremental portion, so as to develop a plurality of first correlated signals each related to the time integral of at least one of said plurality of first product signals; and
,combining said plurality of first correlated signals so as to develop a first output signal representing a first response of the array to returns from object points within said incremental portion.
1 Assignment
0 Petitions
Accused Products
Abstract
A scanner includes a scan head having a linear array of transducers Xn, and a transmitter 106 which excites the transducers in response to transmit signals TRn from a reference generator 110 so that the transducers emit a plurality of successive bursts of ultrasonic energy, each burst producing a transmitted beam which is steered and focused along a radially-extending scan line. To effect received beam steering and focusing, received signals Sn from the transducers are supplied to a processor 112 along with associated in-phase binary reference signals bn(R) and quadrature binary reference signals bn(I). The received signal is multiplied by a reference signal and the product is integrated for a specific time duration whose time occurrence is used to steer and focus the beam. Processor 112 is responsive to WRITE SELECT, READ SELECT and SAMPLE signals from reference generator 110 to correlate each signal Sn with its associated reference signals during a plurality of successive resolution windows, each of which corresponds to a distinct incremental area along a scan line, so as to provide in-phase and quadrature output signals Re and Im each representing a response of the array to reflections from successive incremental areas along a scan line. Signals Re and Im are combined by processors 114 and 116 to develop output signals A and .0. representing, respectively, the amplitude and phase of returns from successive incremental areas along a scan line. Information for transmitted and received beam steering and focusing is stored in a phase pattern memory 118A, and extracted therefrom by a controller 118 in a predetermined order and supplied to reference generator 110.
-
Citations
25 Claims
-
1. A method for steering and focusing the received beam of an array of ultrasonic transducers to an incremental portion of an object, each transducer being adapted to provide a received signal representing returns of ultrasonic energy from object points of the object, said method comprising the steps of:
-
providing a plurality of first reference signals, each first reference signal being associated with one of the received signals and having a frequency and phase that are matched to the frequency and phase of those components in the associated received signal that represent returns from object points within said incremental portion; multiplying each received signal by its associated first reference signal so as to develop a plurality of first product signals each related to the product of a received signal and its associated first reference signal; integrating each of said plurality of first product signals during an associated one of a plurality of resolution windows, the time occurrence of each said resolution window being substantially equal to the time occurrence of those components in the received signal, from which the associated said first product signal has been developed, that represent returns from object points within said incremental portion, so as to develop a plurality of first correlated signals each related to the time integral of at least one of said plurality of first product signals; and
,combining said plurality of first correlated signals so as to develop a first output signal representing a first response of the array to returns from object points within said incremental portion. - View Dependent Claims (2, 3, 4, 5, 6)
-
-
7. In an ultrasonic beamforming method wherein the electrical signal from each ultrasonic transducer in an array thereof is multiplied by an associated signal whose frequency and phase are related in a predetermined manner to the frequency and phase of the electrical signal in order to develop a product signal related to the product of the electrical signal and its associated reference signal, the improvement comprising the step of integrating each said product signal over a predetermined resolution window whose time duration determines the extent of an incremental portion of an object scanned by the array and whose time occurrence determines the relative location of said incremental portion within the object.
-
8. An apparatus for steering and focusing the received beam of an array of ultrasonic transducers to an incremental portion of an object, each transducer being adapted to provide a received signal representing returns of ultrasonic energy from object points of the object, said apparatus comprising:
-
first means for providing a plurality of first reference signals, each first reference signal being associated with one of the received signals and having a frequency and phase that are matched to the frequency and phase of those components in the associated received signal that represent returns from object points within said incremental portion; second means for multiplying each received signal by its associated first reference signal so as to develop a plurality of first product signals each related to the product of a received signal and its associated first reference signal; third means for integrating each of said plurality of first product signals during an associated one of a plurality of resolution windows, the time occurrence of each said resolution window being substantially equal to the time occurrence of those components in the received signal, from which the associated first product signal has been developed, that represent returns from object points within said incremental portion, so as to develop a plurality of first correlated signals each related to the time integral of at least one of said plurality of first product signals; and
,fourth means for combining said plurality of first correlated signals so as to develop a first output signal representing a first response of the array to returns from object points within said incremental portion. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
-
-
23. An apparatus, adapted to be used with a plurality of ultrasonic transducers arranged in an array, for processing received signals from the transducers that represent returns of a transmitted burst of ultrasonic energy from object points of an object, so as to form a received beam that is steered and focused to each of a plurality of successive incremental portions of the object, said apparatus comprising:
-
signal generator means for providing a plurality n of reference signals, each said reference signal being associated with one of the received signals; means for multiplying each received signal by its associated reference signal so as to develop a plurality n of product signals, each said product signal being related to the product of the instantaneous magnitudes of a received signal and its associated reference signal; means for combining said plurality n of product signals into a lesser plurality m of group product signals, each said group product signal comprising a current whose magnitude is related to the sum of those ones of said plurality of product signals that have been developed from the received signals provided by a group of adjacent transducers in the array; a plurality k of capacitance storage means; switching matrix means adapted to selectively couple each of said plurality m of group product signals to each of said plurality k of capacitance storage means; readout means adapted to selectively sample the total charge on each of said plurality k of capacitance storage means and to discharge each said capacitance storage means when so sampled; and
,wherein said signal generator means is operative to cause said switching matrix means to successively couple each said group product signal to different ones of said plurality k of capacitance storage means during an associated plurality of successive resolution windows, each of whose time occurrence and time duration corresponds to the time occurrence and time duration of those components in the received signals, from which each said group product signal has been developed, that represent returns of ultrasonic energy from object points within a unique one of said plurality of incremental portions, so that a given one of said plurality k of capacitance storage means receives charge contributions from each of said plurality m of group product signals for a unique one of said plurality of incremental portions, and wherein said signal generator means is further operative to cause said readout means to sample the total charge on a given one of said plurality k of capacitance storage means whenever all charge contributions for a unique one of said plurality of incremental portions have been made.
-
-
24. An ultrasonic scanner for providing a scanner output signal useful in constructing a real-time, two-dimensional sector image of an object, said scanner comprising:
-
a plurality of ultrasonic transducers arranged in a linear array; a transmitter for producing a transmitted beam of ultrasonic energy by exciting said plurality of ultrasonic transducers so that said transducers emit successive bursts of ultrasonic energy, each of which propagates outwardly from the array along a radially-extending scan line; a processor for steering and focusing a received beam along each said scan line by processing a plurality of received signals from said plurality of ultrasonic transducers that represent returns of each transmitted burst of ultrasonic energy from object points of the object, said processor being operative;
to multiply said plurality of received signals by a corresponding plurality of in-phase reference signals and by a corresponding plurality of quadrature reference signals to develop a plurality of in-phase and a plurality of quadrature product signals;
to integrate each of said plurality of in-phase product signals and each of said plurality of quadrature product signals over a plurality of resolution windows established by a plurality of select signals, each said resolution window representing the expected time occurrence of returns of the transmitted burst of ultrasonic energy from a unique incremental area of the object along said scan line, so as to develop a plurality of in-phase and a plurality of quadrature correlated signals; and
, to successively combine those ones of said plurality of in-phase correlated signals and those ones of said plurality of quadrature product signals that correspond to each incremental area along said scan line so as to respectively provide an in-phase output signal and a quadrature output signal each having a succession of values corresponding to successive incremental areas along said scan line;means for combining the successive values of said in-phase and quadrature output signals to provide said scanner output signal which has a succession of values each representing the amplitude of returns from object points within a distinct incremental area along said scan line; a reference generator for providing said plurality of in-phase reference signals, said plurality of quadrature reference signals, and said plurality of select signals, said reference generator being adapted to adjust the relative phasing of said plurality of in-phase reference signals and said plurality of quadrature reference signals and to adjust the relative time occurrences of said plurality of resolution windows established by each of said plurality of select signals in response to information transferred thereto; and
,a controller including a phase pattern memory having stored therein a plurality of sets of receive information, each said set comprising the information required to steer said received beam along a unique scan line and to focus said received beam to each of said plurality of incremental areas along said unique scan line, said controller being operative to successively extract, from said phase pattern memory, said plurality of sets of receive information and to successively transfer the thus-extracted sets of receive information to said reference generator. - View Dependent Claims (25)
-
Specification