# US 7,744,536 B2 · Multi stage beamforming

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- Number: US 7,744,536 B2
- Document ID: US7744536B2
- Status: Granted
- Kind: B2
- Application number: 11/904,660
- Filed: 2007-09-27
- Published: 2008-01-31
- Granted: 2010-06-29
- Earliest claimed: 2005-03-25
- Assignees: Siemens Medical Solutions USA, Inc.
- Inventors: John C. Lazenby
- Web page: https://patentgrep.com/patent/US7744536B2

## CPC

- G03B 42/06: using ultrasonic, sonic or infrasonic waves
- A61B 8/4483: {characterised by features of the ultrasound transducer}
- G01S 7/52044: {Scan converters}
- G01S 7/52095: {using multiline receive beamforming}
- A61B 8/00: Diagnosis using ultrasonic, sonic or infrasonic waves
- G03B: APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR (optical parts of such apparatus G02B; photosensitive materials or processes for photographic purposes G03C; apparatus for processing exposed photographic materials G03D)
- A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D)
- G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES

## Abstract

Beamforming for N elements in performed in log(N) steps of complexity O(N). The signals measured at each element are treated as a receive beam formed by that element with a beam width equal to the element pattern or the width of the transmit illumination. In each of multiple stages, the number of elements is halved by effectively doubling the pitch. The number of beams formed by each element is doubled by narrowing the beam width by a factor of 2 in sin(θ). Since steering and focusing are separated, a single set of delays are applied to each element signal individually prior to the multi-stage beam forming for each finite depth. The data is in a sector format, but by using two beamforming steps, data in a Vector® format is provided.

## Claims

### Claim 1

A method for ultrasound beamforming data from a region received at an array, the method comprising:
receiving N signals at a respective N elements, the N signals being a data set, the signals responsive to a region of a patient;
applying a first stage operable to increase by a second factor from the data set to a number X of data sets and reduce the N signals by a first factor to M signals in each of the X data sets;
applying a second stage operable to increase from the X number of data sets by a fourth factor to Y number of data sets and reduce the M signals by a third factor to O signals in each of the Y data sets; and
generating an image as a function of the data of each of the Y data sets;
wherein the first, second, third and fourth factors are selected to provide the X data sets and the Y data sets with a narrower beamwidth relative to the data set.

### Claim 2 (depends on 1)

The method of claim 1 wherein the second and fourth factors are 2 and the first and third factors are ½.

### Claim 3 (depends on 1)

The method of claim 1 wherein applying the first stage comprises:
steering the N signals in first and second different directions, the N signals steered in the first direction being a first of the X number of data sets and the N signals steered in the second direction being a second of the X number of data sets;
filtering the first and second data sets; and
decimating the first and second data sets responsive to the filtering.

### Claim 4 (depends on 3)

The method of claim 3 wherein applying the second stage comprises repeating the steering, filtering and decimating for each of the first and second sets responsive to the decimating.

### Claim 5 (depends on 1)

The method of claim 1 wherein X times M equals N and Y times O equals N.

### Claim 6 (depends on 5)

The method of claim 5 further comprising applying additional stages, each additional stage increasing the number of data sets and decreasing the number of signals in each data set, a final stage providing a single value for each data set.