Digital scanline signal processor for an ultrasonic diagnostic imaging system

• US 6,050,942 A
• Filed: 07/11/1997
• Issued: 04/18/2000
• Est. Priority Date: 07/11/1997
• Status: Expired due to Fees

• Current Assignee: Advanced Technology Materials, Inc. (Entegris Incorporated)
• Original Assignee: ATL Ultrasound Incorporated
• Inventors: Rust, David W., Pedersen, Robert H., Roundhill, David N.
• Primary Examiner(s): Lateef, Marvin M.
• Assistant Examiner(s): PATEL, MAULIN M
• Application Number:
  US08/893,426
• Time in Patent Office: 1,012 Days
• Field of Search: 600/455, 600/454, 600/456, 600/449, 600/443
• US Class Current: 600/437
• CPC Class Codes: A61B 8/00 Diagnosis using ultrasonic, sonic or infrasonic waves imaging of objects using sonar G01S15/00
• CPC Class Codes: G01S 15/8979 Combined Doppler and pulse-echo imaging systems
• CPC Class Codes: G01S 7/52026 Extracting wanted echo signals Doppler systems G01S15/50; Doppler short range imaging systems G01S15/8979
• CPC Class Codes: G01S 7/52034 Data rate converters
• CPC Class Codes: G01S 7/52077 with means for elimination of unwanted signals, e.g. noise or interference
• CPC Class Codes: G01S 7/52095 using multiline receive beamforming

Abstract

A digital scanline signal processor which processes beamformed echo signals includes a normalization circuit, a speckle reduction processor, and a gain stage which amplifies detected echo signals. The normalization circuit applies depth dependent gain to the scanline signals to equalize the amplitudes in channels of the processor with different passband characteristics. A log compression circuit includes two compression functions for low level and high level echo signals.

Claims

1. An ultrasonic diagnostic imaging system comprising:

a multiline beamformer for producing signals of at least two coherent scanlines in response to one transmit interval; and

a speckle reduction circuit coupled to receive said coherent scanline signals from said multiline beamformer, for reducing the speckle content of said scanline signals.

2. The ultrasonic diagnostic imaging system of claim 1, wherein said speckle reduction circuit comprises a frequency compounding circuit.

19. The ultrasonic diagnostic imaging system of claim 1, wherein said coherent scanline signals are applied to said speckle reduction circuit over parallel digital paths.

20. The ultrasonic diagnostic imaging system of claim 1, wherein said coherent scanline signals are applied to said speckle reduction circuit in a time interleaved format.

3. An ultrasonic diagnostic imaging system, including a beamformer for producing signals of coherent scanlines, comprising:

a normalization circuit for compensating for the effects of different apertures during the reception of echo signals;

a multiple channel scanline processing circuit for processing said scanlines with different response characteristics;

a processor for equalizing the nominal signal amplitudes of said multiple channels; and

means for combining said differently processed scanlines.

4. The ultrasonic diagnostic imaging system of claim 3, wherein said equalizing processor comprises a depth dependent processor.

5. The ultrasonic diagnostic imaging system of claim 4, wherein said depth dependent processor comprises a time gain control circuit.

6. The ultrasonic diagnostic imaging system of claim 4, wherein said depth dependent processor applies different gain versus depth characteristics to different ones of said multiple channels.

7. An ultrasonic diagnostic imaging system, including a beamformer for producing signals of coherent scanlines, comprising:

an interpolator responsive to said coherent scanline signals for producing coherent interpolated scanline signals; and

a speckle reduction circuit coupled to receive said interpolated scanline signals, for reducing the speckle content of said signals.

9. The ultrasonic diagnostic imaging system of claim 7, wherein said interpolator includes a line buffer.

8. An ultrasonic diagnostic imaging system, including a beamformer for producing signals of coherent scanlines, comprising:

an interpolator responsive to said coherent scanline signals for producing interpolated scanline signals; and

a speckle reduction circuit coupled to receive said interpolated scanline signals, for reducing the speckle content of said signals,

wherein said beamformer comprises a multiline beamformer.

10. An ultrasonic diagnostic imaging system, including a beamformer for producing signals of coherent scanlines, comprising:

an interpolator responsive to said coherent scanline signals for producing interpolated scanline signals; and

a speckle reduction circuit coupled to receive said interpolated scanline signals, for reducing the speckle content of said signals,

wherein said interpolator includes a line buffer, and

wherein said line buffer is further used to form a synthetic aperture.

11. An ultrasonic diagnostic imaging system, including a beamformer for producing signals of coherent scanlines, comprising:

a normalization circuit for compensating for the effects of different apertures during the reception of echo signals;

a detector for detecting normalized scanline signals; and

a gain stage coupled to the output of said detector,

wherein said gain stage applies a gain which has been partitioned between said normalization circuit and said gain stage.

12. The ultrasonic diagnostic imaging system of claim 11, wherein the gain of said normalization circuit is controlled to prevent the attainment of undesired saturation levels during processing between said normalization circuit and said gain stage.

18. The ultrasonic diagnostic imaging system of claim 12, wherein said log compression circuit exhibits a first compression function for low level echo signals, and a second compression function for high level echo signals.

13. An ultrasonic diagnostic imaging system, including analog circuitry which amplifies received ultrasonic echo signals and a beamformer coupled to receive said ultrasonic echo signals for producing signals of coherent scanlines, comprising:

a detector for detecting said scanline signals; and

a gain stage coupled to the output of said detector,

wherein said beamformer comprises a digital beamformer;

wherein the gain of said analog circuitry is chosen in consideration of the dynamic range of said digital beamformer; and

wherein said gain stage applies a gain which is selected in consideration of the gain of said analog circuitry.

14. The ultrasonic diagnostic imaging system of claim 13, wherein said analog circuitry includes TGC circuitry.

15. The ultrasonic diagnostic imaging system of claim 13, wherein said digital beamformer includes a plurality of analog to digital converters, each exhibiting a given dynamic range.

16. The ultrasonic diagnostic imaging system of claim 13, wherein the gain of said gain stage is chosen in consideration of the brightness of an ultrasonic image.

17. An ultrasonic diagnostic imaging system, including a beamformer coupled to receive said ultrasonic echo signals for producing signals of coherent scanlines, comprising:

a detector for detecting said scanline signals; and

a log compression circuit coupled to receive detected scanline signals,

wherein said log compression circuit exhibits at least two compression characteristics.