Methods and apparatus for ultrasound imaging

1. A method for automatically deriving gain compensating data from ultrasound image data comprising:

receiving ultrasound image data corresponding to an image scan, wherein the ultrasound image data is based on ultrasound signals attenuated by tissue;

assembling an image frame from the ultrasound image data, the image frame having columns and rows of image data values where columns represent lateral position and rows represent axial position;

partitioning the image data frame into a plurality of sections including associated image data values;

for each of the plurality of sections, calculating a representative signal value based on the image data values associated with the section;

calculating a gain variation between representative signal values of each pair of adjacent sections by:

choosing one of the plurality of sections as a reference section;

choosing a distribution direction from a position of the reference section to perform gain variation calculations;

for each of the plurality of sections, for gain variation calculations proceeding in the distribution direction, subtracting a representative signal value of a section from a representative signal value of an adjacent section, a distance from the adjacent section to the reference section being greater than a distance from the section to the reference section; and

for each of the plurality of sections, for gain variation calculations not proceeding in the distribution direction, subtracting a representative signal value of a section from a representative signal value of an adjacent section, a distance from the adjacent section to the reference section being less than a distance from the section to the reference section;

calculating gain variation distribution series values from the calculated gain variations based on the distribution direction;

calculating a gain variation curve from the gain variation distribution series values; and

calculating a gain compensation curve from the gain variation curve,

wherein a value of the gain compensation curve corresponds with a position.

2. The method according to claim 1 further comprising:

examining each image data value in the frame for values outside of a lower and upper limit; and

flagging the image data values outside the predefined lower and upper limits for non-use.

3. The method according to claim 2 wherein the ultrasound imaging data comprises RF data, IF data, baseband signal data, or line data.

4. The method according to claim 3 wherein the representative signal value for each section is calculated using histograms, percentile value, mean, median and mode.

5. The method according to claim 4 wherein each section includes the same number of image data values, a different number of image data values, or image data values shared with an adjacent section.

6. The method according to claim 1 wherein calculating the gain variation between representative signal values of each pair of adjacent sections further comprises:

for gain variation calculations proceeding in the distribution direction, subtracting the representative signal value of the reference section from the representative signal value of the adjacent section if the adjacent section is next to the reference section; and

for gain variation calculations not proceeding in the distribution direction, subtracting the representative signal value of the section from the representative signal value of the reference section if the adjacent section is next to the reference section.

7. The method according to claim 6 wherein calculating the gain variation distribution series values comprises:

using the representative signal value of the reference section as one gain variation distribution series value; and

creating a new gain variation distribution series value by adding a gain variation to a previous gain variation distribution series value if in the distribution direction, or by subtracting a gain variation from a previous gain variation distribution series value if not in the distribution direction.

8. The method according to claim 7 wherein the gain variation curve is calculated by a curve fit or interpolation of the gain variation distribution series values in order.

9. The method according to claim 8 wherein a gain compensation curve is calculated by changing the polarity of the gain variation curve.

10. The method according to claim 6 further comprising comparing an absolute value of each gain variation value with a predetermined limit wherein if an absolute gain variation value is greater than the predetermined limit, substituting a zero for that gain variation value.

11. The method according to claim 6 further comprising comparing an absolute value of each gain variation values with a predetermined limit wherein if an absolute gain variation value is greater than the predetermined limit, substituting a predetermined value for that gain variation value.

12. The method according to claim 6 wherein the plurality of sections are axial sections.

13. The method according to claim 6 wherein the plurality of sections are lateral sections.

14. A method for automatically deriving gain compensating data for an ultrasound image volume comprising:

receiving ultrasound image data corresponding to a plurality of consecutive image scans, wherein the ultrasound image data is based on ultrasound signals attenuated by tissue;

assembling an image volume from the plurality of image scans, the image volume having three dimensions of image data values where columns represent lateral position, rows represent axial position, and frames represent elevation position;

partitioning the volume into a plurality of volume sections including associated image data values;

for each of the plurality of volume sections, calculating a representative signal value based on the image data values associated with the volume section;

calculating a gain variation between representative signal values of each pair of adjacent volume sections by:

choosing one of the plurality of volume sections as a reference volume section;

choosing a distribution direction from a position of the reference volume section to perform gain variation calculations;

for each of the plurality of volume sections, for gain variation calculations proceeding in the distribution direction, subtracting a representative signal value of a volume section from a representative signal value of an adjacent volume section, distance from the adjacent volume section to the reference volume section being greater than a distance from the volume section to the reference volume section; and

for each of the plurality of volume sections, for gain variation calculations not proceeding in the distribution direction, subtracting a representative signal value of a volume section from a representative signal value of an adjacent volume section, a distance from the adjacent volume section to the reference volume section being less than a distance from the volume section to the reference volume section;

calculating gain variation distribution series values from the calculated gain variations based on the distribution direction;

calculating a gain variation curve from the gain variation distribution series values; and

calculating a gain compensation curve from the gain variation curve,

wherein a value of the gain compensation curve corresponds with a position.

15. The method according to claim 14 further comprising:

examining each image data value in the volume image for values outside of a predefined lower and upper limit; and

flagging the image data values outside the lower and upper limits for non-use.

16. The method according to claim 15 wherein the ultrasound imaging data comprises RF data, IF data, baseband signal data, line data or image data.

17. The method according to claim 16 wherein the representative signal value for each volume section is calculated using histograms, percentile value, mean, median and mode.

18. The method according to claim 17 wherein each volume section includes the same number of image data values, a different number of image data values, or image data values shared with an adjacent volume section.

19. The method according to claim 14 wherein calculating the gain variation between representative signal values of each pair of adjacent volume sections further comprises:

for gain variation calculations proceeding in the distribution direction, subtracting the representative signal value of the reference volume section from the representative signal value of the adjacent volume section if the adjacent volume section is next to the reference volume section; and

for gain variation calculations not proceeding in the distribution direction, subtracting the representative signal value of the volume section from the representative signal value of the reference volume section if the adjacent volume section is next to the reference volume section.

20. The method according to claim 19 wherein calculating the gain variation distribution series values comprises:

using the representative signal value of the reference volume section as one gain variation distribution series value; and

creating a new gain variation distribution series value by adding a gain variation to a previous gain variation distribution series value if in the distribution direction, or by subtracting a gain variation from a previous gain variation distribution series value if not in the distribution direction.

21. The method according to claim 20 wherein the gain variation curve is calculated by a curve fit of the gain variation distribution series values in order.

22. The method according to claim 21 wherein a gain compensation curve is calculated by changing the polarity of the gain variation curve.

23. The method according to claim 19 further comprising comparing an absolute value of each gain variation value with a predetermined limit wherein if an absolute gain variation value is greater than the predetermined limit, substituting a zero for that gain variation value.

24. The method according to claim 19 further comprising comparing an absolute value of each gain variation values with a predetermined limit wherein if an absolute gain variation value is greater than the predetermined limit, substituting a predetermined value for that gain variation value.

25. The method according to claim 19 wherein the plurality of volume sections are elevation volume sections.

26. The method according to claim 19 wherein the plurality of volume sections are axial volume sections.

27. The method according to claim 19 wherein the plurality of volume sections are lateral volume sections.

28. An automatic gain compensation system for deriving gain compensating data for ultrasound systems having amplifiers configured to adjust a received signal's gain while acquiring ultrasound image data, the automatic gain compensation system comprising:

an automatic gain processor configured for:

receiving ultrasound image data corresponding to an image scan, wherein the ultrasound image data is based on ultrasound signals attenuated by tissue;

assembling an image frame from the ultrasound image data, the image frame having columns and rows of image data values where columns represent lateral position and rows represent axial position;

partitioning the image data frame into a plurality of sections including associated image data values;

for each of the plurality of sections, calculating a representative signal value based on the image data values associated with the section;

calculating a gain variation between representative signal values of each pair of adjacent sections by:

choosing one of the plurality of sections as a reference section;

choosing a distribution direction from a position of the reference section to perform gain variation calculations;

for each of the plurality of sections, for gain variation calculations proceeding in the distribution direction, subtracting a representative signal value of a section from a representative signal value of an adjacent section, a distance from the adjacent section to the reference section being greater than a distance from the section to the reference section; and

for each of the plurality of sections, for gain variation calculations not proceeding in the distribution direction, subtracting a representative signal value of a section from a representative signal value of an adjacent section, a distance from the adjacent section to the reference section being less than a distance from the section to the reference section;

calculating gain variation distribution series values from the calculated gain variations based on the distribution direction;

calculating a gain variation curve from the gain variation distribution series values; and

calculating a gain compensation curve from the gain variation curve, wherein a value of the gain compensation curve corresponds with a position.

29. An automatic gain compensation system for deriving gain compensating data for ultrasound systems having amplifiers configured to adjust a received signal's gain while acquiring ultrasound image data, the automatic gain compensation system comprising:

an automatic gain processor configured for:

receiving ultrasound image data corresponding to a plurality of consecutive image scans, wherein the ultrasound image data is based on ultrasound signals attenuated by tissue;

assembling an image volume from the plurality of image scans, the image volume having three dimensions of image data values where columns represent lateral position, rows represent axial position, and frames represent elevation position;

partitioning the volume into a plurality of volume sections including associated image data values;

for each of the plurality of volume sections, calculating a representative signal value based on the image data values associated with the volume section;

calculating a gain variation between representative signal values of each pair of adjacent volume sections by:

choosing one of the plurality of volume sections as a reference volume section;

choosing a distribution direction from a position of the reference section to perform gain variation calculations;

for each of the plurality of volume sections, for gain variation calculations proceeding in the distribution direction, subtracting a representative signal value of a volume section from a representative signal value of an adjacent volume section, distance from the adjacent volume section from the reference volume section being greater than a distance from the volume section to the reference volume section; and

for each of the plurality of volume sections, for gain variation calculations not proceeding in the distribution direction, subtracting a representative signal value of a volume section from a representative signal value of an adjacent volume section a distance from the adjacent volume section to the reference volume section being less than a distance from the volume section to the reference volume section;

calculating gain variation distribution series values from the calculated gain variations based on the distribution direction;

calculating a gain variation curve from the gain variation distribution series values; and

calculating a gain compensation curve from the gain variation curve,

wherein a value of the gain compensation curve corresponds with a position.