RECEIVE BEAMFORMER FOR ULTRASOUND

• US 20090326375A1
• Filed: 06/18/2009
• Published: 12/31/2009
• Est. Priority Date: 06/27/2008
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: MAGEE, DAVID P
• Granted Patent: US 8,834,369 B2
• Time in Patent Office: Days
• US Class Current: 600/443
• CPC Class Codes: G01S 15/8915 using a transducer array
• CPC Class Codes: G01S 7/52046 Techniques for image enhancement involving transmitter or receiver image enhancement by image data processing G06T5/00
• CPC Class Codes: G10K 11/346 using phase variation

Abstract

A method of ultrasound receive beamforming includes receiving a first plurality of sensing signals from target tissue, forming a first plurality of digital sensing signals, and data processing the digital sensing signals along a first plurality of data paths to form a first plurality of delayed and apodized digital sensing signals. Data path combining generates data combinations of the delayed and apodized digital sensing signals to include two or more of the delayed and apodized digital sensing signals that originate from different ones of the transducer elements. The data combinations are interpolation filtered using a plurality of interpolation filters to form a second plurality of delayed and apodized digital sensing signals, which are then summed to form an ultrasound receive beamformed signal. The interpolation filters can be interpolation filters in a single shared filter bank, with each interpolation filter providing a different fractional delay.

Claims

1. A method of ultrasound receive beamforming, comprising:

receiving a first plurality of sensing signals from a first plurality of transducer elements that originate from a target tissue region of interest;

digitizing said first plurality of sensing signals to form a first plurality of digital sensing signals;

data processing said first plurality of digital sensing signals along a first plurality of data paths to form a first plurality of delayed and apodized digital sensing signals;

data path combining for generating data combinations of said first plurality of delayed and apodized digital sensing signals to include two or more of said first plurality of delayed and apodized digital sensing signals that originate from different ones of said first plurality of transducer elements;

interpolation filtering said data combinations using a plurality of interpolation filters, said plurality of interpolation filters filtering said data combinations to form a second plurality of delayed and apodized digital sensing signals, and

summing said second plurality of delayed and apodized digital sensing signals after said interpolation filtering to form an ultrasound receive beamformed signal.

2. The method of claim 1, wherein said plurality of interpolation filters comprise a plurality of interpolation filters arranged in a single shared interpolation filter bank, said plurality of interpolation filters each providing a different fractional delay.

3. The method of claim 2, wherein said different fractional delays are given by integer*Tres, wherein Tres is a timing resolution (Tres) for said ultrasound receive beamformed signal and said integer corresponds to integer values from zero to ceil(Ts/Tres)−

1, where Ts is a sampling period for said digitizing.

4. The method of claim 3, wherein said ultrasound receive beamformed signal z[n] at a time sample n for a scan line in said ultrasound receive beamformed signal is calculated using:

$z<br><br>\left[n\right]=\underset{k=-\mathrm{\infty <br><br>}}{\overset{\mathrm{\infty <br><br>}}{\sum <br><br>}}<br><br>\underset{m=0}{\overset{M-1}{\sum <br><br>}}<br><br>a_m<br><br>\left[n\right]<br><br>h_{p<br><br>\left(m,n\right)}<br><br>\left[k\right]<br><br>x_m<br><br>\left[n-k-d_m<br><br>\left[n\right]\right]$

wherein;

m is a summation over a number of said first plurality of transducer elements;

k is a summation over a number of interpolation filter coefficients for said plurality of interpolation filters;

a_m[n] is an apodization factor applied during said data processing for an m^th receive signal at time sample n,

x_m[n] is a received signal from the m^th of said first plurality of transducer elements at time sample n.

h_p(m,n)[k] is the k^th coefficient of the p(m,n)^th of said plurality of interpolation filters at time sample n.

d_m[n] is an integer delay for said received signal from the m^th of said first plurality of transducer elements at time sample n;

p(m,n)ε

{0,1, . . . , P−

1}

P=ceil(T_s/T_res)

5. The method of claim 2, wherein said data combinations are implemented by a switching circuit that receives a control signal that is operable to direct any of said first plurality of delayed and apodized digital sensing signals to any of said plurality of interpolation filters.

6. The method of claim 1, wherein said first plurality of transducer elements comprise piezoelectric transducers.

7. The method of claim 1, wherein said ultrasound receive beamforming comprises beamforming over a plurality of scan lines, said ultrasound receive beamforming comprising Multiple Line Acquisition (MLA).

8. The method of claim 1, wherein said interpolation filtering comprise FIR polyphase interpolation filtering.

9. The method of claim 5, wherein said first plurality of transducer elements comprise at least 32 elements, and said data processing, said data path combining and said interpolation filtering are performed exclusively by a single DSP IC.

10. The method of claim 5, wherein said data processing, said data path combining and said interpolation filtering are performed by a plurality of DSP ICs hooked in parallel, each of said plurality of DSP ICs providing said data processing, said data path combining and said interpolation filtering for a portion of said first plurality of sensing signals from a subset of said first plurality of transducer elements.

11. An ultrasound diagnostic imaging system, comprising:

a plurality of transducer elements for transmitting ultrasound transmit pulses toward a target tissue region of interest, and receiving echo signals from said target tissue region of interest in response to said transmit pulses;

a transmit section for driving said plurality of transducer elements for said transmitting of said ultrasound transmit pulses, and

a receive section for processing a first plurality of sensing signals generated by said plurality of transducers responsive to said echo signals, said receive section comprising;

a first plurality of data processing circuit blocks each operable for digitizing, delaying and apodizing one of said first plurality of sensing signals to form a first plurality of delayed and apodized digital sensing signals;

data path combining circuitry for generating data combinations of said first plurality of delayed and apodized digital sensing signals to include two or more of said first plurality of delayed and apodized digital sensing signals that originate from different ones of said first plurality of transducer elements;

an interpolation filter bank coupled to an output of said data path combining circuitry for interpolation filtering said data combinations to generate a second plurality of delayed and apodized digital sensing signals;

a summer for summing said second plurality of delayed and apodized digital sensing signals to form a beamformed signal,

a backend imaging display processor coupled to receive and process said beamformed signal to generate a display signal, said display signal being suitable for causing display devices to produce an image, and

a display device for receiving said display signal and producing said image.

12. The system of claim 11, wherein said interpolation filter bank comprises a single shared interpolation filter bank comprising a plurality of interpolation filters, said plurality of interpolation filters each providing a different fractional delay.

13. The system of claim 12, wherein said different fractional delays are based on integer*Tres, wherein Tres is a timing resolution (Tres) for said ultrasound receive beamformed signal and said integer corresponds to integer values from zero to ceil(Ts/Tres)−

1, where Ts is a sampling period for said digitizing.

14. The system of claim 13, wherein said beamformed signal z[n] at a time sample n for a scan line is calculated using:

$z<br><br>\left[n\right]=\underset{k=-\mathrm{\infty <br><br>}}{\overset{\mathrm{\infty <br><br>}}{\sum <br><br>}}<br><br>\underset{m=0}{\overset{M-1}{\sum <br><br>}}<br><br>a_m<br><br>\left[n\right]<br><br>h_{p<br><br>\left(m,n\right)}<br><br>\left[k\right]<br><br>x_m<br><br>\left[n-k-d_m<br><br>\left[n\right]\right]$

wherein;

m is a summation over a number of said first plurality of transducer elements;

k is a summation over a number of interpolation filter coefficients for said plurality of interpolation filters;

a_m[n] is an apodization factor applied during said data processing for an m^th receive signal at time sample n,

x_m[n] is a received signal from the m^th of said first plurality of transducer elements at time sample n.

h_p(m,n)[k] is the k^th coefficient of the p(m,n)^th of said plurality of interpolation filters at time sample n.

d_m[n] is an integer delay for said received signal from the m^th of said first plurality of transducer elements at time sample n;

p(m,n)ε

{0,1, . . . , P−

1}

P=ceil(T_s/T_res)

15. The system of claim 12, wherein said data path combining circuitry is implemented by a switching circuit that receives a control signal that is operable to direct any of said first plurality of delayed and apodized digital sensing signals to any of said plurality of interpolation filters.

16. The system of claim 11, wherein said first plurality of transducer elements comprise at least 32 elements, further comprising a single DSP IC for providing said first plurality of data processing circuit blocks, said data path combining circuitry, and said interpolation filter bank.

17. The system of claim 11, wherein said system comprises a plurality of DSP ICs, wherein each of said plurality of DSP ICs provide said first plurality of data processing circuit blocks, said data path combining circuitry, and said interpolation filter bank for said processing for a portion of said first plurality of sensing signals from a subset of said first plurality of transducer elements.

18. A digital signal processor (DSP) IC for ultrasound signal processing, comprising:

a substrate having a semiconductor surface;

delaying and apodizing circuitry for processing a first plurality of digitized ultrasound sensing signals to form a first plurality of delayed and apodized digital ultrasound sensing signals;

data path combining circuitry for generating data combinations of said first plurality of delayed and apodized digital sensing signals to include two or more of said first plurality of delayed and apodized digital sensing signals that originate from different ones of said first plurality of transducer elements, and

an interpolation filter bank coupled to an output of said data path combining circuitry for interpolation filtering said data combinations to generate a second plurality of delayed and apodized digital sensing signals.

19. The DSP IC of claim 18, wherein said interpolation filter bank comprises a plurality of interpolation filters, said plurality of interpolation filters each providing a different fractional delay.

20. The DSP IC of claim 19, wherein said different fractional delays are based on integer*Tres, wherein Tres is a timing resolution (Tres) for said ultrasound receive beamformed signal and said integer corresponds to integer values from zero to ceil(Ts/Tres)−

1, where Ts is a sampling period for said digitizing.

21. The DSP IC of claim 19, wherein said data path combining circuitry comprises a switching circuit that receives a control signal generated by said DSP IC that is operable to direct any of said first plurality of delayed and apodized digital sensing signals to any of said plurality of interpolation filters.