TRANSMIT BEAMFORMING IN 3-DIMENSIONAL ULTRASOUND

• US 20090005684A1
• Filed: 06/28/2007
• Published: 01/01/2009
• Est. Priority Date: 06/28/2007
• Status: Active Grant

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Halvorsroed, Thomas, Haider, Bruno Hans, Kristoffersen, Kjell, Bjaerum, Steinar
• Granted Patent: US 8,096,951 B2
• Time in Patent Office: Days
• US Class Current: 600/447
• CPC Class Codes: A61B 8/4461 Features of the scanning mechanism, e.g. for moving the transducer within the housing of the probe
• CPC Class Codes: A61B 8/4483 characterised by features of the ultrasound transducer
• CPC Class Codes: A61B 8/4488 the transducer being a phased array
• CPC Class Codes: A61B 8/4494 characterised by the arrangement of the transducer elements devices for short-range imaging using particular transducer elements arrangements under G01S15/8909; arrangements of transducers in generation of mechanical vibrations of infrasonic, sonic or ultrasonic frequency B06B1/0607
• CPC Class Codes: A61B 8/483 involving the acquisition of a 3D volume of data
• CPC Class Codes: B06B 2201/76 Medical, dental
• CPC Class Codes: G01S 15/8925 the array being a two-dimensional transducer configuration, i.e. matrix or orthogonal linear arrays
• CPC Class Codes: G01S 15/8927 using simultaneously or sequentially two or more subarrays or subapertures
• CPC Class Codes: G03B 42/06 using ultrasonic, sonic or infrasonic waves

Abstract

An ultrasound system comprises a probe including a two-dimensional (2D) array of transducer elements that form an aperture having a plurality of receive elements that are configured to receive ultrasound signals. The transducer elements form at least one transmit sub-aperture that is configured to be interconnected with a fixed group of the transducer elements within the aperture. Transmitters generate electrical transmit signals, and at least one transmit sub-aperture processor (tx SAP) maps the transducer elements within the fixed group of the transducer elements to the transmitters in a transmit configuration based on a beam steering direction.

Claims

1. An ultrasound system comprising:

a probe including a two-dimensional (2D) array of transducer elements that form an aperture having a plurality of receive elements that are configured to receive ultrasound signals, the transducer elements forming at least one transmit sub-aperture that is configured to be interconnected with a fixed group of the transducer elements within the aperture;

transmitters for generating electrical transmit signals; and

at least one transmit sub-aperture processor (tx SAP) for mapping the transducer elements within the fixed group of the transducer elements to the transmitters in a transmit configuration based on a beam steering direction.

2. The ultrasound system of claim 1, further comprising:

the at least one tx SAP comprising a cross-point switch;

system channels interconnected with the transmitters and the cross-point switch for conveying the transmit signals there-between; and

a SAP controller configured to control the cross-point switch to select the transducer elements within the fixed group of the transducer elements to be driven by one of the system channels based on the transmit configuration.

3. The ultrasound system of claim 1, further comprising:

system channels interconnected with the transmitters for conveying the transmit signals; and

a processor configured to determine delays associated with each of the transducer elements within the fixed group of the transducer elements, the delays being based at least on the beam steering direction, the at least one tx SAP being configured to assign at least one of the transducer elements within the fixed group of transducer elements to one channel of the system channels based on the delays.

4. The ultrasound system of claim 1, wherein the plurality of receive elements are configured to form receive sub-apertures, the at least one transmit sub-aperture comprising at least two adjacent receive sub-apertures.

5. The ultrasound system of claim 1, the system further comprising a SAP controller configured to divide the receive elements of the at least one transmit sub-aperture into two element groups that are oriented with respect to each other by one of horizontally, vertically and diagonally, the two element groups forming different transmit configurations for steering the transmit signals in different directions.

6. The ultrasound system of claim 1, wherein the at least one tx SAP comprises at least one cross-point switch for interconnecting the fixed group of the transducer elements and the transmitters, the at least one cross-point switch having at least one switch for each of the transducer elements within the fixed group of the transducer elements.

7. The ultrasound system of claim 1, further comprising:

system channels for conveying the transmit signals between the transmitters and the at least one tx SAP; and

a processor being configured to determine a maximum delay and a minimum delay based at least on the beam steering direction and delays associated with the transducer elements within the fixed group of transducer elements, the processor further configured to determine intermediate delays based on at least the maximum and minimum delays, the processor assigning one of the maximum delay, the minimum delay and the intermediate delays to each of the system channels.

8. The ultrasound system of claim 1, further comprising:

receivers for receiving electrical receive signals;

system channels for conveying the transmit signals between the transmitters and the at least one tx SAP;

the tx SAP comprising at least one cross-point switch for interconnecting a group of the system channels with the fixed group of transducer elements; and

preamplifiers for receiving the receive signals from the cross-point switch, the system channels further configured to convey the receive signals between the preamplifiers and the receivers.

9. A method for transmitting ultrasound signals using a 2D array of transducer elements, comprising:

forming at least one transmit sub-aperture comprising a fixed group of transducer elements for transmitting ultrasonic transmit signals and at least two receive sub-apertures for receiving ultrasonic receive signals, the at least one transmit sub-aperture and the at least two receive sub-apertures being associated with a predetermined group of system channels;

calculating a delay for each of the transducer elements within the fixed group of transducer elements, wherein the delay is based at least on a steering angle associated with the transducer element and a transmit operation; and

connecting at least a portion of the transducer elements within the fixed group of transducer elements to the predetermined group of system channels based at least on the delays associated with the transducer elements.

10. The method of claim 9, wherein the transmit and receive sub-apertures comprise the same transducer elements.

11. The method of claim 9, further comprising:

determining a maximum delay and a minimum delay based on the delays for each of the transducer elements within the fixed group of transducer elements;

determining intermediate delays based on the maximum and minimum delays, the intermediate delays being further based on a total number of system channels within the predetermined group of system channels; and

assigning channel delays to each of the system channels based on the maximum delay, the minimum delay and the intermediate delays, the connecting further comprising connecting each of the transducer elements within the fixed group of transducer elements to one of the system channels based on a smallest magnitude difference between the delay of the transducer element and the channel delay assigned to the system channel.

12. The method of claim 9, wherein the connecting further comprises distributing the transducer elements within the fixed group of transducer elements between the system channels of the predetermined group of system channels based on one of load balancing and uniform quantization.

13. The method of claim 9, further comprising:

identifying a center frequency associated with the ultrasonic transmit signal; and

identifying the delays that are greater than a predetermined number of periods of the transmitted center frequency, wherein the transducer elements within the fixed group of transducer elements that are associated with the identified delays are one of modified by subtracting at least one period of the center frequency and not connected to the system channels.

14. The method of claim 9, further comprising minimizing an optimization criterion based on at least one of an average mean-square delay error and a maximum side lobe level of a transmitted beam profile, the connecting at least a portion of the transducer elements within the fixed group of transducer elements to the predetermined group of system channels being further based on the minimizing.

15. An ultrasound system comprising:

a probe including a 2D array of transducer elements that form an aperture having a plurality of receive elements that are configured to receive ultrasound signals;

at least one configurable cross-point switch having first and second sides, the at least one configurable cross-point switch being interconnected with a fixed group of the transducer elements on a first side, the fixed group of the transducer elements forming a transmit sub-aperture configured to transmit ultrasound signals;

system channels being configured to convey at least the transmit ultrasound signals, the system channels interconnecting with the at least one configurable cross-point switch on the second side, the at least one configurable cross-point switch comprising at least one switch associated with each of the transducer elements within the fixed group of the transducer elements, the at least one configurable cross-point switch connecting at least one of the transducer elements with one of the system channels; and

a sub-aperture processor (SAP) controller configured to control the at least one configurable cross-point switch to map each of the transducer elements within the fixed group of transducer elements to the system channels in a transmit configuration based on delays associated with ultrasound transmit signals.

16. The ultrasound system of claim 15, wherein the transmit sub-aperture is divided into at least first and second receive sub-apertures, wherein the first and second receive sub-apertures comprise first and second predetermined subsets of transducer elements from within the fixed group of transducer elements for receiving the ultrasound signals.

17. The ultrasound system of claim 15, wherein the transmit sub-aperture is divided into at least first and second receive sub-apertures, wherein the first and second receive sub-apertures comprise first and second predetermined subsets of transducer elements from within the fixed group of transducer elements, wherein the at least one configurable cross-point switch is further configured to map the first and second predetermined subsets of transducer elements to a first system channel and a second system channel, respectively, from within the system channels for receiving the ultrasound signals.

18. The ultrasound system of claim 15, wherein the SAP controller is further configured to determine a maximum delay and a minimum delay based at least on a delay associated with each of the transducer elements, the SAP controller further configured to determine intermediate delays based on at least the maximum and minimum delays, the SAP controller further configured to assign one of the maximum delay, the minimum delay and the intermediate delays to each of the system channels.

19. The ultrasound system of claim 15, further comprising:

at least one receive SAP for processing the received ultrasound signals detected by the plurality of receive elements;

a receive SAP die including the at least one receive SAP; and

a transmit SAP die including the at least one configurable cross-point switch and further comprising input and output switches, the input switches inputting the receive ultrasound signals to the at least one receive SAP and the output switches receiving output signals from the at least one receive SAP.

20. The ultrasound system of claim 15, wherein the at least one configurable cross-point switch comprises at least one switch for each of the transducer elements within the group.