Ultrasound imaging with multiple single-element transducers and ultrasound signal propagation correction using delay and sum beamforming based on a cross-correlation function

A method for ultrasound imaging with a first single-element transducer and a second single-element transducer, wherein the first and second single-element transducers are disposed on an ultrasound probe shaft, which has a longitudinal axis, with transducing sides disposed transverse to and facing away from the longitudinal axis, the first and second single-element transducers are angularly offset from each other on the shaft by a non-zero angle, the method, comprising:

• operating the first and second single-element transducers at first and second different cutoff frequencies;
• concurrently translating and rotating the shaft, moving the first and second single-element transducers along a helical path while the first and second single-element transducers acquire first and second echo signals;
• receiving first electrical signals from the first single-element transducer, wherein the first electrical signals are indicative of the first echo signals, and receiving second electrical signals from the second single-element transducer, wherein the second electrical signals are indicative of the second echo signals;
• delay and sum beamforming, with first and second adaptive synthetic aperture focusing beamformers, the first and second electrical signals, respectively via different processing chains, employing adaptive synthetic aperture focusing, producing first and second images,
• wherein the adaptive synthetic aperture focusing corrects calculated first and second delays for transducer position errors with first and second corrections, weights and delays the first and second electrical signals with first and second weights and the corrected calculated first and second delays, and adaptively sums the weighted and delayed first and second electrical signals respectively based on first and second adaptive weight coefficients, producing the first and second images,
• wherein the delay and sum beamforming includes:
• delaying the first electrical signals with first delays determined by a first beam model to generate delayed first electrical signals, wherein the first electrical signals include jitter, determining first deviations in propagation between the delayed first electrical signals and first reference signals that do not include jitter by cross-correlating central signals of the first reference signals with the delayed first electrical signals, determining the first corrections based on the first deviations, delaying the second electrical signals with second delays determined by a second beam model to generate delayed second electrical signals, wherein the second electrical signals include jitter, by cross-correlating central signals of the second reference signals with the delayed second electrical signals, and
• wherein the delay and sum beamforming is based on a cross-correlation function:
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• 〉
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• y
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• where y0 is a central signal, yn is a signal of the delayed electrical signals, ·;· is an inner product, and ∥·∥ is a norm;
• combining the first and second images, creating a final image, which has reduced speckle noise and higher contrast resolution relative to the first and second images;
• and
• displaying the final image.