Frequency-domain beamforming

Patent metadata

Field	Value
Publication number	US-9778557-B2
Application number	US-201314097281-A
Country	US
Kind code	B2
Filing date	Dec 5, 2013
Priority date	Dec 6, 2012
Publication date	Oct 3, 2017
Grant date	Oct 3, 2017

Abstract

A method includes receiving from multiple transducers respective signals including reflections of a transmitted signal from a target. An image of the target is produced irrespective of sparsity of the received signals, by computing transducer-specific frequency-domain coefficients for each of the received signals, deriving, from the transducer-specific frequency-domain coefficients, beamforming frequency-domain coefficients of a beamformed signal in which the reflections received from a selected direction relative to the transducers are emphasized, and reconstructing the image of the target at the selected direction based on the beamforming frequency-domain coefficients.

First claim

The invention claimed is:

1. A method, comprising:
receiving via an input interface signals from multiple respective transducers, the received signals comprising reflections of a transmitted signal from both dominant reflectors and speckle reflectors in a target;
using processing circuitry that is coupled to the input interface, reconstructing an image of the target, by:
computing transducer-specific frequency-domain coefficients for each of the received signals;
deriving, from the transducer-specific frequency-domain coefficients, beamforming frequency-domain coefficients of a beamformed signal in which the reflections received from a selected direction relative to the transducers are emphasized; and
reconstructing the image of the target at the selected direction, including reconstructing and imaging both the dominant reflectors and the speckle reflectors, based on the beamforming frequency-domain coefficients, without constraining the received signals to be sparse.

2. The method according to claim 1 , wherein deriving the beamforming frequency-domain coefficients comprises computing the beamforming frequency-domain coefficients only within an effective bandwidth of the beamformed signal.

3. The method according to claim 1 , wherein reconstructing the image comprises applying an inverse Fourier transform to the beamforming frequency-domain coefficients.

4. The method according to claim 1 , wherein deriving the beamforming frequency-domain coefficients comprises computing the beamforming frequency-domain coefficients only within a partial sub-band within an effective bandwidth of the beamformed signal.

5. The method according to claim 1 , wherein reconstructing the image comprises applying a Compressed sensing (CS) or sparse recovery process to the beamformed frequency-domain coefficients.

6. The method according to claim 1 , wherein reconstructing the image comprises applying to the beamformed frequency-domain coefficients an algorithm for extracting sinusoids from a sum of sinusoids.

7. The method according to claim 1 , wherein reconstructing the image comprises estimating the beamformed signal in time-domain based on the beamforming frequency-domain coefficients, and reconstructing the image from the estimated beamformed signal.

8. The method according to claim 1 , wherein deriving the beamforming frequency-domain coefficients comprises computing a weighted average of the transducer-specific frequency-domain coefficients.

9. The method according to claim 8 , wherein computing the weighted average comprises applying to the transducer-specific frequency-domain coefficients predefined weights that are independent of the received signals.

10. The method according to claim 1 , wherein computing the transducer-specific frequency-domain coefficients comprises deriving the transducer-specific frequency-domain coefficients from sub-Nyquist samples of the received signals.

11. The method according to claim 1 , wherein reconstructing the image comprises applying an l1-norm optimization to the beamforming frequency-domain coefficients.

12. The method according to claim 1 , wherein reconstructing the image comprises applying a recovery process that exploits sparse structure of the received signals.

13. The method according to claim 1 , wherein reconstructing the image comprises applying a recovery process that assumes the received signals are compressible but does not constrain the received signals to be sparse.

14. Apparatus, comprising:
an input interface, which is configured to receive signals from multiple respective transducers, the received signals comprising reflections of a transmitted signal from both dominant reflectors and speckle reflectors in a target; and
processing circuitry, which is configured to compute transducer-specific frequency-domain coefficients for each of the received signals, to derive, from the transducer-specific frequency-domain coefficients, beamforming frequency-domain coefficients of a beamformed signal in which the reflections received from a selected direction relative to the transducers are emphasized, and to reconstruct an image of the target at the selected direction based on the beamforming frequency-domain coefficients, including reconstructing and imaging both the dominant reflectors and the speckle reflectors, without constraining the received signals to be sparse.

15. The apparatus according to claim 14 , wherein the processing circuitry is configured to compute the beamforming frequency-domain coefficients only within an effective bandwidth of the beamformed signal.

16. The apparatus according to claim 14 , wherein the processing circuitry is configured to reconstruct the image by applying an inverse Fourier transform to the beamforming frequency-domain coefficients.

17. The apparatus according to claim 14 , wherein the processing circuitry is configured to compute the beamforming frequency-domain coefficients only within a partial sub-band within an effective bandwidth of the beamformed signal.

18. The apparatus according to claim 14 , wherein the processing circuitry is configured to reconstruct the image by applying a Compressed sensing (CS) or sparse recovery process to the beamformed frequency-domain coefficients.

19. The apparatus according to claim 14 , wherein the processing circuitry is configured to reconstruct the image by applying to the beamformed frequency-domain coefficients an algorithm for extracting sinusoids from a sum of sinusoids.

20. The apparatus according to claim 14 , wherein the processing circuitry is configured to estimate the beamformed signal in time-domain based on the beamforming frequency-domain coefficients, and to reconstruct the image from the estimated beamformed signal.

21. The apparatus according to claim 14 , wherein the processing circuitry is configured to derive the beamforming frequency-domain coefficients by computing a weighted average of the transducer-specific frequency-domain coefficients.

22. The apparatus according to claim 21 , wherein the processing circuitry is configured to compute the weighted average by applying to the transducer-specific frequency-domain coefficients predefined weights that are independent of the received signals.

23. The apparatus according to claim 14 , wherein the processing circuitry is configured to derive the transducer-specific frequency-domain coefficients from sub-Nyquist samples of the received signals.

24. The apparatus according to claim 14 , wherein the processing circuitry is configured to reconstruct the image by applying an l1-norm optimization to the beamforming frequency-domain coefficients.

Assignees

• Technion Res & Dev Foundation

Inventors

• Eldar Yonina
• Chernyakova Tatiana
• Amit Ron

Classifications

• G10K11/343

  using frequency variation or different frequencies · CPC title

• G01S7/52025 Primary

  for pulse systems (G01S7/52034 takes precedence) · CPC title

• A61B8/52

  Devices using data or image processing specially adapted for diagnosis using ultrasonic, sonic or infrasonic waves · CPC title

• G01S7/32

  Shaping echo pulse signals; Deriving non-pulse signals from echo pulse signals · CPC title

• G03B42/06 Primary

  using ultrasonic, sonic or infrasonic waves · CPC title