Ultrasound image enhancement and super-resolution

• US 9,188,664 B2
• Filed: 05/30/2014
• Issued: 11/17/2015
• Est. Priority Date: 05/31/2013
• Status: Active Grant

• Current Assignee: Eagleyemed, Inc.
• Original Assignee: Eagleyemed, Inc.
• Inventors: Hiriyannaiah, Harish P.
• Primary Examiner(s): HULKA, JAMES R
• Application Number:
  US14/292,431
• Publication Number:
  US 20140355377A1
• Time in Patent Office: 536 Days
• Field of Search: 367/7
• US Class Current: 1/1
• 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 voltage pulses within the handheld probe in a firing sequence in which a selection of active piezoelectric crystals is varied over time in a sequence selected to shift a spatial center of a transmitted ultrasound pulse over the firing sequence to achieve at least ½

piezoelectric transducer crystal physical resolution.

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 over the firing sequence.

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

6. The method of claim 1, wherein a number of active piezoelectric crystals is varied over the firing sequence.

7. The method of claim 1, wherein a spatial distribution of active piezoelectric crystals is varied over the firing sequence.

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, further comprising 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 Sin c 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 probe housing;

an array of piezoelectric transducers, wherein each piezoelectric transducer includes a piezoelectric crystal; and

beam forming and control electronics within the probe housing to shape a gain and a delay of voltage pulses coupled to the array of the piezoelectric transducers with a firing sequence in which a selection of active piezoelectric crystals is varied over time in a sequence selected to shift a spatial center of a transmitted ultrasound pulse over the firing sequence to achieve at least ½

piezoelectric transducer crystal physical resolution.

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 over the firing sequence.

19. The ultrasound probe of claim 15, wherein a number of active piezoelectric crystals is varied over the firing sequence.

20. The ultrasound probe of claim 19, further comprising applying time varying focus coefficients for the detected ultrasound pulses to improve spatial focus.

21. The ultrasound probe of claim 15, wherein a distribution of active piezoelectric crystals is varied over the firing sequence.

22. The ultrasound probe of claim 15, further comprising detecting reflected ultrasound pulses in the ultrasound probe.

23. The ultrasound probe of claim 15, wherein the ultrasound probe 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.

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

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