Hewlett-packard Company

Raymond A Beaudin

Joseph R Fallon

Leslie I Halberg

Sydney M Karp

Jerome F Witt

Michael P Anthony

A delay generator for a beamformer in a phased array ultrasound imaging system is provided. The beamformer processes received signals from an array of transducer elements to form a receive beam. The beamformer includes a delay generator corresponding to each transducer element for delaying the received signal. The delay generator includes a delay unit and a delay controller. The delay is variable in response to a change delay signal supplied by the delay controller at discrete times during reception of ultrasound energy. According to one feature of the invention, the delay represents an exact solution, within the quantization error of the delay unit, to the delay equation for the delay at a given steering angle, transducer element and focal depth. According to another feature of the invention, the delay controller generates a change delay signal that steers the receive beam to a dynamically variable steering angle and dynamically focuses the receive beam during reception of ultrasound energy.

Delay generator for phased array ultrasound beamformer

An ultrasound imaging system where a location in the image has associated with it an amplitude and a velocity derived from a doppler shift assigns a detection strength to each location. Detection strength is a mapping from each possible combination of the amplitude and velocity into a scalar value that represents the likelihood that the velocity is not an artifact of the noise in the environment. The detection strength values are spatially filtered and then used to determine whether to accept or reject the measured velocity. A more optimistic filtering strategy for the measured velocity is now possible, and cooperates with a filtered detection strength to trim away suspicious regions in the image. The filtered detection strength signal can be used to compensate for unwanted side effects of other filtering done during the processing of the measured parameters. When the number of input bits exceeds the address space of a ROM filtering digital representations of measured parameters, the input values can be bifurcated into MSB's and LSB's, with the MSB's applied to the ROM as the address. The LSB's are sent to a MUX. The output value produced by each input combination can include two fields, one of which is the filtered or transformed value of the applied MSB's, and the other of which is a selector field. The selector field is pre-encoded to direct the MUX to select the LSB's that ought to be associated with the filtered or transformed value produced by the ROM in the other field. These recovered LSB's are then conjoined or otherwise used with that filtered or transformed value. The corduroy artifact of parallel flow operation can be removed by incorporating into the lateral detection strength filter a weighting scheme wherein the sum of the weights for the odd numbered radials in the filter's aperture equals the sum of the weights for the even numbered radials in the filter's aperture.

Method and apparatus for a detection strength spatial filter in an

A system for displaying selected images on a video display device is provided. One or more sources of image frames are included which sources may be digital or analog and which sources may present pixel data in different selected formats. A frame memory is provided which is adapted to store a plurality of memory frames each of which may store one or more image frames to be displayed. Image frames are selectively stored in the memory frames of the frame memory in the format in which they are received. The images may be stored in full size or may be compressed for windowing display and selected information concerning image frames may be utilized to control the mapping of values stored for the pixels of the image frames. A display frame may be formed of two or more compressed image frames with each image frame being read out from a selected memory frame which memory frame may be independent of or the same as the memory frame for other read out images. Certain images may contain two or more different types of information which may be selectively processed when read out from a frame memory to cause the content of such multiple information images to be displayed as multiple separate images containing the content of the image frame in various permutations and combinations. Color mapping using the same or different criteria may also be provided, with the color mapping being independent for each of the image frames being simultaneously displayed.

Method and apparatus for the simultaneous display of one or more

An asymmetric finite impulse response digital filter, typically used in an ultrasound imaging system, includes forward and reverse sections. In the forward section, a group of input data samples is multiplied by a set of filter coefficients in a forward order to provide first intermediate results. The first intermediate results are summed to provide a first output sample. In the reverse section, the group of input data samples is multiplied by the set of coefficients in a reverse order as compared with the forward section to provide second intermediate results. The second intermediate results are summed to provide a second output sample. The process is repeated to provide multiple first and second output samples. A signal estimation unit estimates a characteristic of the input data samples, such as the frequency of a Doppler ultrasound signal, based on the first and second output samples. The filter provides twice as many output samples as prior art filters for a given set of input data samples. The filter is preferably used as a clutter filter to remove low frequency clutter from a Doppler ultrasound signal.

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Windham, NH, United States of America

Raymond A Beaudin