Row-column addressed 2-D array with a double curved surface

1. An ultrasound imaging system, comprising:

a transducer array, comprising:

a row-column addressed 2-D array of transducer elements, wherein the row-column addressed 2-D array comprises:

a first array of 1-D arrays of elements;

a second array of 1-D arrays of elements, which is orthogonal to the first array; and

a double-curved surface;

transmit circuitry configured to convey an excitation pulse to the transducer array;

receive circuitry configured to receive a signal indicative of an ultrasound echo from the transducer array;

a beamformer configured to generate ultrasound image data with the received signal and time-of-flight distances for each of the elements of the transducer elements,

wherein the beamformer is configured to compute, for each of one of the first array or the second array, a time-of-flight distance from each of the elements to an imaging point P, for all imaging points of interest, as BP + PA , where BP =√{square root over ( BP TX proj 2 + P TX proj P 2 )}, P TX proj P is a line segment from the imaging point P to a perpendicular projection P TX proj ( 1014 ) of the imaging point P and BP TX proj is a line segment computed by subtracting a vector pointing from a curved surface center to the perpendicular projection P TX proj by a fixed radius of the curved surface, and where PA =√{square root over ( AP RX proj 2 + P RX proj P 2 )}, P RX proj P is a line segment from the imaging point P to a perpendicular projection P RX proj ( 1026 ) of the imaging point P and AP TX proj is a line segment computed by subtracting the line segment from the curved surface center to the perpendicular projection P RX proj by the fixed radius of the curved surface; and

a display configured to display the ultrasound image data.

2. The ultrasound imaging system of claim 1 , wherein the double-curved surface is a lens.

3. The ultrasound imaging system of claim 2 , wherein the lens is a convex lens.

4. The ultrasound imaging system of claim 3 , wherein the convex lens is a spherical lens.

5. The ultrasound imaging system of claim 2 , wherein the lens has a same curvature in two orthogonal directions.

6. The ultrasound imaging system of claim 2 , wherein the lens has a first curvature in a direction of the first array and a second curvature in a direction of the second array, wherein the first and second curvatures are different.

7. The ultrasound imaging system of claim 2 , wherein the lens has a first thickness at a periphery and a second thickness at a center region, and the first thickness is greater than the second thickness.

8. The ultrasound imaging system of claim 2 , wherein the lens is centered over the 2-D array.

9. The ultrasound imaging system of claim 2 , wherein the lens is disposed off-center with respect to the 2-D array.

10. The ultrasound imaging system of claim 2 , wherein the 2-D array has a first imaging region and the combination of the 2-D array and the lens has a second imaging region, and the second imaging region is larger than the first imaging region.

11. The ultrasound imaging system of claim 2 , wherein the lens is a Fresnel lens.

12. The ultrasound imaging system of claim 1 , wherein the transducer elements include triangular shaped elements that provide integrated apodization that linearly scales an output pressure transmitted by the elements of a periphery and electrical signal generated by the elements of the periphery.

13. The ultrasound imaging system of claim 1 , wherein the curved surface is an active transducing surface of the 2-D array.

14. The ultrasound imaging system of claim 1 , wherein the 2-D array includes piezoelectric or capacitive micromachined ultrasonic transducer transducing elements.

15. The ultrasound imaging system of claim 1 , further comprising:

a controller configured to control the transmit circuitry for two-way focusing to focus the set of 1-D column array elements or the set of 1-D row array elements.

16. The ultrasound imaging system of claim 1 , wherein the beamformer is configured to determine a shortest distance from a source to a point to a drain for each column and each row for a plurality of points in an imaging field of view.

17. The ultrasound imaging system of claim 16 , wherein the beamformer sums coherently low resolution beamformed images for a point for all transmissions.

18. The ultrasound imaging system of claim 16 , wherein the point is from a group consisting of inside the planes, outside of the planes and on a plane.

19. A method, comprising:

transmitting an ultrasound signal with a first array of a 2-D row-column addressed transducer array with a curved surface;

receiving an echo signal with a second array of the 2-D row-column addressed transducer array with the curved surface, where the 2-D row-column addressed transducer array includes transducer elements and the first and second arrays are perpendicular;

beamforming the echo signal to create ultrasound image data with the received signal and time-of-flight distances for each of the elements of the transducer elements, wherein the beamforming includes computing, for each of one of the first array or the second array, a time-of-flight distance from each of the elements to an imaging point P, for all imaging points of interest, as BP + PA , where BP =√{square root over ( BP TX proj 2 + P TX proj P 2 )}, P TX proj P is a line segment from the imaging point P to a perpendicular projection P TX proj of the imaging point P and BP TX proj is a line segment computed by subtracting a vector pointing from a curved surface center to the perpendicular projection P TX proj by a fixed radius of the curved surface, and where PA =√{square root over ( AP RX proj 2 + R RX proj P 2 )}, P RX proj P is a line segment from the imaging point P to a perpendicular projection P RX proj of the imaging point P and AP TX proj is a line segment computed by subtracting the line segment from the curved surface center to the perpendicular projection P RX proj by the fixed radius of the curved surface; and

displaying the image.

20. A computer readable medium encoded with computer readable instructions, which when executed cause a processor to:

transmit an ultrasound signal with a first array of a 2-D row-column addressed transducer array with a curved surface;

receive an echo signal with a second array of the 2-D row-column addressed transducer array with the curved surface, where the 2-D row-column addressed transducer array includes transducer elements and the first and second arrays are perpendicular;

beamform the echo signal to create ultrasound image data with the received signal and time-of-flight distances for each of the elements of the transducer elements, wherein the beamforming includes computing, for each of one of the first array or the second array, a time-of-flight distance from each of the elements to an imaging point P, for all imaging points of interest, as BP + PA , where BP =√{square root over ( BP TX proj 2 + P TX proj P 2 )}, P TX proj P is a line segment from the imaging point P to a perpendicular projection P TX proj of the imaging point P and BP TX proj is a line segment computed by subtracting a vector pointing from a curved surface center to the perpendicular projection P TX proj by a fixed radius of the curved surface, and where PA =√{square root over ( AP RX proj 2 + P RX proj P 2 )}, P RX proj P is a line segment from the imaging point P to a perpendicular projection P RX proj of the imaging point P and AP TX proj is a line segment computed by subtracting the line segment from the curved surface center to the perpendicular projection P RX proj by the fixed radius of the curved surface; and

displaying the image.