Acuson Corporation

J Nelson Wright

Albert Gee

Christopher R Cole

Samuel H Maslak

David J Finger

Donald R Langdon

Ismayil M Guracar

Gregory L Holley

Jay Sterling Plugge

D Grant Fash, Iii

Brian M Normand

Hugh G Larsen

An ultrasonic imaging system and method form first and second transmit beams characterized by a complex phase separation angle (e.g. 90&deg;) that differs from an integer multiple of 180&deg; along the same steering angle. First and second backscattered signals are received in response to these transmit beams, and the first and second backscattered signals are combined in a weighted sum. By properly selecting the weighting factors and the separation angle, the resulting combined signal can be provided with various advantageous features, such as a selective reduction in negative frequency components, a selective enhancement of fundamental frequency components, or a selective enhancement of harmonic frequency components.

Medical diagnostic ultrasonic imaging transmit/receive method and apparatus

The present invention includes a fully programmable plurality of multi-channel receivers, each receiver having a digital multi-channel receive processor and a local processor control. Each receive processor includes a first decimator, time delay memory, second decimator, and complex multiplier. The receive beamformer is a computationally efficient system which is programmable to allow processing mode trade-offs among receive frequency, receive spatial range resolution, and number of simultaneous beams received. Each local control receives focusing data from a central control computer and provides final calculation of per-channel dynamic focus delay, phase, apodization, and calibration values for each receiver signal sample. Further, this invention includes a baseband multi-beam processor which has a phase aligner and a baseband filter for making post-beamformation coherent phase adjustments and signal shaping, respectively. The phase aligner maintains scan-line-to-scan-line coherency, such as would be required for coherent image formation. Accordingly, the present system can operate under multiple imaging formats, using a variety of transducers and a variety of modes such as B-mode, M-mode, and color Doppler flow mode.

Method and apparatus for receive beamformer system

This invention presents a multi-beam baseband processor for making post-beamformation adjustments to the complex (in-phase/quadrature) pre-detection scan line samples acquired from a receive beamformer of an ultrasound imaging system. Specifically, the invention includes a programmable finite impulse response (FIR) filter and a programmable complex multiplier. The programmable filter performs signal shaping and sample-rate conversion. The signal shaping capability may be used to compensate for transducer and analog signal path responses, to increase signal-to-noise ratio (SNR) by rejecting out-of-band noise frequencies, to operate as a matched filter to the transmitted waveform shape, and to act as both a smoothing and anti-aliasing filter during rate-conversion operation. The programmable multiplier permits both amplitude and phase adjustments of the complex data that assures amplitude and phase coherency between acquired scan lines, compensating for the effects of a selected scan format or the differences in ultrasound frequencies used to produce each scan line.

Method and apparatus for a baseband processor of a receive beamformer

A method and apparatus are provided for imaging an object using a transducer array for transmitting one or more beams that are steered and/or translated to transmit scan lines for multiple excitation events so as to scan a field of view of the object, for sensing received signals reflected from the object after each excitation event on one or more receive beams on receive scan lines, and for transducing those sensed received signals into corresponding electrical signals. The method and apparatus is additionally for acquiring and storing coherent samples retaining both phase and amplitude information of those electrical signals obtained on the receive scan lines throughout at least a portion of the field of view, and for combining stored coherent samples associated with distinct receive beams to synthesize new coherent image samples aligned on synthetic scan lines which are distinct from any one of (1) receive scan lines on which a signal was sensed, (2) transmit scan lines on which a signal was directed, or (3) transmit scan lines and receive scan lines. The method and apparatus is further for detecting the synthesized coherent image samples and displaying or recording the resulting image field.

Method and apparatus for coherent image formation

This invention presents, a multi-beam baseband processor for making post-beamformation adjustments to the complex (in-phase/quadrature) pre-detection scan line samples acquired from a receive beamformer of an ultrasound imaging system. Specifically, the invention includes a programmable finite impulse response (FIR) filter and a programmable complex multiplier. The programmable filter performs signal shaping and sample-rate conversion. The signal shaping capability may be used to compensate for transducer and analog signal path responses, to increase signal-to-noise ratio (SNR) by rejecting out-of-band noise frequencies, to operate as a matched filter to the transmitted waveform shape, and to act as both a smoothing and anti-aliasing filter during rate-conversion operation. The programmable multiplier permits both amplitude and phase adjustments of the complex data that assures amplitude and phase coherency between acquired scan lines, compensating for the effects of a selected scan format or the differences in ultrasound frequencies used to produce each scan line.

The invention provides a method and system for adaptive persistence processing in an ultrasound imaging system. Acoustic signals are temporally filtered using an adaptive persistence filter, having a recursive stage followed by a nonrecursive stage. A set of filtering coefficients for each stage are supplied by a look-up table in a memory, addressed or indexed in response to a plurality of input or output pixel values. The look-up table may therefore embody any selected function of its input variables. The input variables for the look-up table function are a current input pixel value X.sub.n and a previous intermediate pixel value W.sub.n-1, and the function embodied by the look-up table includes a relative first difference function for selecting a filter coefficient. A recursive filtering coefficient .alpha. is held constant over time, while a nonrecursive filtering coefficient .gamma.is adjusted dynamically in response to the current input pixel value X.sub.n and the previous intermediate pixel value W.sub.n-1. The non-recursive stage filter has a frequency response that attenuates higher frequency components without attenuating a broad range of lower frequency components, relative to the recursive stage frequency response. The step response or settling time of the non-recursive stage filter always spans one frame interval, independent of the nonrecursive filtering coefficient, while the step response or settling time for the recursive stage filter is generally longer and is dependent on the recursive filtering coefficient.

Adaptive persistence processing

A method and an apparatus are provided for storage and retrieval of measured aberration correction values used in adaptive focus ultrasound imaging. The aberration correction values, corresponding to an aberration region in an imaged subject, are measured at a transmit focal depth. The measured aberration correction values, typically delays, from a measurement depth are stored in a geometric aberration transform (GAT.TM.) table and transformed to aberration correction values at other focal depths for correcting the focus of both transmit and receive beamformers. The transformation is accomplished by using a geometric aberration transform (GAT.TM.) index table which retrieves one or more aberration correction values in the table for any desired depth.

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Menlo Park, CA, United States of America

J Nelson Wright