ULTRASOUND IMAGE ENHANCEMENT AND SUPER-RESOLUTION

• US 20150092515A1
• Filed: 12/09/2014
• Published: 04/02/2015
• Est. Priority Date: 05/31/2013
• Status: Active Grant

• Current Assignee: Eagleyemed, Inc.
• Original Assignee: Eagleyemed, Inc.
• Inventors: HIRIYANNAIAH, Harish P.
• Granted Patent: US 9,194,941 B2
• Time in Patent Office: Days
• US Class Current: 367/7
• 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: B06B 1/0215 for generating pulses, e.g. bursts of oscillations, envelopes
• CPC Class Codes: G01S 15/02 using reflection of acoustic waves G01S15/66 takes precedence
• CPC Class Codes: G01S 7/52017 particularly adapted to short-range imaging G01S7/53 takes precedence
• CPC Class Codes: G01S 7/5202 for pulse systems
• CPC Class Codes: G01S 7/52034 Data rate converters
• CPC Class Codes: G01S 7/52047 for elimination of side lobes or of grating lobes; for increasing resolving power
• CPC Class Codes: G01S 7/5208 with integration of processing functions inside probe or scanhead
• CPC Class Codes: G01S 7/52085 Details related to the ultrasound signal acquisition, e.g. scan sequences control of medical diagnostic ultrasound devices A61B8/54
• CPC Class Codes: G10K 11/26 Sound-focusing or directing, e.g. scanning
• CPC Class Codes: G10K 11/341 Circuits therefor

Abstract

Techniques to improve resolution in an ultrasound system are disclosed. An exemplary apparatus is a portable ultrasound probe having transducer elements and supporting electronics within the probe. The beam is shaped to split the resolution to sub-pixel accuracy. Super resolution sample technique based on interpolation can be used to further increase resolution. In one embodiment the ultrasound system supports ½ crystal physical resolution and ¼ crystal digital resolution.

Claims

1. A method of providing super-resolution in an ultrasound imaging system having a handheld probe including piezoelectric transducer having an array of piezoelectric crystals, comprising:

generating ultrasound pulses, including generating high voltage pulses within the handheld probe in a firing sequence selected to drive the array of piezoelectric transducer crystals such that the gain and a delay of each high voltage pulse coupled to the array of piezoelectric transducer crystals splits the resolution to sub-pixel accuracy;

detecting reflected ultrasound pulses;

performing scan conversion within the handheld probe; and

outputting ultrasound images.

2. The method of claim 1, wherein the firing sequence is selected to achieve ½

piezoelectric transducer crystal physical resolution and interpolation is performed to achieve ¼

piezoelectric crystal digital resolution.

3. The method of claim 1, wherein the array of piezoelectric crystals has a number of piezoelectric transducer crystals in the range of 64 to 128 crystals.

4. The method of claim 3, wherein the firing sequence is selected to shift a transmitted beam focus by ½

piezoelectric transducer crystal physical resolution in each cycle of a firing sequence.

5. The method of claim 4, further comprising performing interpolation in the scan convertion to increase a number of samples in scan line conversion.

6. The method of claim 1, wherein the gain and delay of each pulse in the firing sequence has a fine-grained temporal apodization.

7. The method of claim 1, wherein the gain and delay of each pulse in the firing sequence has a fine-grained spatial apodization.

8. The method of claim 1, further comprising detecting reflected ultrasound pulses in the ultrasound probe with a sub-pixel resolution.

9. The method of claim 8, applying time varying focus coefficients for the detected ultrasound pulses to improve spatial focus.

10. The method of claim 1, wherein performing scan conversion includes performing scan line conversion of data received from reflected ultrasound pulses, including performing, in a scan line domain, interpolation of samples along a tangential direction.

11. The method of claim 10, wherein the interpolation comprises at least one of wavelet interpolation and spline interpolation.

12. The method of claim 10, wherein the interpolation comprises an orthonormal expansion sampling method.

13. The method of claim 12, wherein the orthonormal expansion is selected from the group consisting of Legendre sampling, Tchebyshev sampling, and Sinc sampling.

14. The method of claim 10, further comprising varying interpolation in radial zones to increase a number of samples in a distal zone region with respect to the transducers.

15. An ultrasound probe, comprising:

a housing;

an array of piezoelectric transducers disposed in a transducer head detachable attached to the housing, wherein each piezoelectric transducer in the array includes a piezoelectric crystal;

a beamformer disposed in the housing, the beamformer including beam forming and control electronics to shape a gain and a delay of high voltage pulses coupled to the array of the piezoelectric transducers with a firing sequence selected to generate a transmitted ultrasound beam shape that splits the resolution to sub-pixel accuracy; and

scan conversion electronics to convert detected reflected ultrasound pulses into ultrasound images.

16. The ultrasound probe of claim 15, wherein the firing sequence is selected to achieve ½

crystal physical resolution and ¼

crystal digital resolution.

17. The ultrasound probe of claim 15, wherein the array of piezoelectric transducers has a number of piezoelectric crystals in the range of 64 to 128 crystals.

18. The ultrasound probe of claim 17, wherein the firing sequence shifts a transmitted beam focus by ½

crystal physical resolution in each cycle of a firing sequence.

19. The ultrasound probe of claim 15, wherein the gain and delay of each pulse in the firing sequence has a fine-grained temporal apodization.

20. The ultrasound probe of claim 15, wherein the gain and delay of each pulse in the firing sequence has a fine-grained spatial apodization.

21. The ultrasound probe of claim 19, wherein the scan conversion electronics applies a time varying focus coefficients for the detected ultrasound pulses to improve spatial focus.

22. The ultrasound probe of claim 15, wherein the scan conversion electronics performs scan line conversion of data received from reflected ultrasound pulses, including performing, in a scan line domain, interpolation to increase a number of samples in scan line conversion.

23. The ultrasound probe of claim 22, wherein the scan conversion electronics performs interpolation to increase a number of samples in scan line conversion.

24. The ultrasound probe of claim 23, wherein the scan conversion electronics performs interpolation in radial zones to increase a number of samples in a distal zone region with respect to the transducers.

25. The ultrasound probe of claim 15, further comprising a calibration module to perform auto-calibration of the ultrasound probe.

26. An ultrasound probe, comprising,

a housing;

an array of piezoelectric transducers disposed in a transducer head detachably attached to the housing, wherein each piezoelectric transducer in the array includes a piezoelectric crystal;

beamforming means to shape a gain and a delay of high voltage pulses coupled to the array of the piezoelectric transducers with a firing sequence to generate a transmitted ultrasound beam shape that splits the resolution to sub-pixel accuracy; and

scan conversion means including interpolation means to increase a number of samples in scan conversion.

27. A method of providing super-resolution in an ultrasound imaging system having a handheld probe including piezoelectric transducer having an array of piezoelectric crystals, comprising:

generating ultrasound pulses, including generating high voltage pulses within the handheld probe in a firing sequence to drive the array of piezoelectric transducer crystals is selected such that a gain and a delay of each high voltage pulse coupled to the array of piezoelectric transducer crystals splits the resolution to sub-pixel accuracy;

detecting reflected ultrasound pulses;

performing scan conversion within the handheld probe for detected reflected ultrasound pulses, including performing, in a scan line domain, interpolation of samples for scan line processing used to reconstruct the ultrasound image; and

outputting ultrasound images.

28. The method of claim 27, wherein the interpolation comprises at least one of wavelet interpolation and spline interpolation.

29. The method of claim 27, wherein the interpolation comprises an orthonormal expansion sampling method.

30. The method of claim 29, wherein the orthonormal expansion is selected from the group consisting of Legendre sampling, Tchebyshev sampling, and Sinc sampling.