Abstract: A portable, configurable and scalable ultrasonic imaging system uses a phased ultrasonic transducer array coupled to a portable, configurable and scalable ultrasonic processor to develop ultrasonic images. When used in conjunction with a sector phased array, the portable, configurable and scalable ultrasonic imaging system uses a processing channel associated with each element in the transducer array to develop the ultrasonic image. When used with a linear or curved linear transducer array, the portable, configurable and scalable ultrasonic processor uses fewer processing channels than transducer elements to develop the ultrasonic image. Since the portable, configurable and scalable ultrasonic processor is scalable, it is able to use a variety of processors, software and transducer arrays to develop a number of different ultrasonic output images.

Abstract: A sub-beamforming method and apparatus are applied to a portable, one-dimensional ultrasonic imaging system. The sub-beamforming circuitry may be included in the probe s assembly housing the ultrasonic transducer, thus minimizing the number of signals that are communicated between the probe assembly and the portable processor included in the imaging system. Including the sub-beamformer in the probe assembly also relieves the portable processor of some of the signal processing tasks. The sub-beamforming apparatus may be implemented digitally or may be implemented using analog components.

Abstract: A flow velocity processor for use in a color flow imaging system having reduced dynamic range requirements with an improved segmentation scan conversion on a pixel by pixel decision using velocity data derived from an autocorrelation vector after conversion to a unit vector, a compressed magnitude of the autocorrelation vector, and the two dimensional magnitude information. An autocorrelation vector processor generates autocorrelation vectors between pairs of N complex samples of at least one set of complex samples, each autocorrelation vector having amplitude and phase information. A unit vector convertor generates a corresponding unity amplitude autocorrelation vector for each processed input set of N complex samples, the phase of each unit amplitude autocorrelation vector being the same as the resultant autocorrelation vector, and the two components of the unit amplitude autocorrelation vector are used for subsequent calculation of the velocity and segmentation into a final color flow image.

Abstract: A method and apparatus are provided for utilizing a digital front end in a phased array system such as an ultrasonic scanning system to simultaneously perform both digital beam formation and scan conversion. Echo signals from each of the N channels of the array aperture are sampled at selected points along returning echo signals. The samples are preferably used to determine a value for each channel for each pixel utilized in the display by, for example, determining a transmit time for such point. The values for each pixel for the N channels are then summed to obtain the value for the pixel. Alternatively, the samples may be taken at uniform intervals along each channel line and the sample values interpolated to obtain values at Y-boundary crossings or sampling may be taken at times determined so that each sample is at a Y-boundary crossing. The Y-boundary crossing sample values are stored and are then summed to obtain coherently enhanced sample values at the crossings.

Abstract: A method and apparatus are provided for gain control in a Doppler or other scan system which projects a plurality of scan lines at a given angle to determine velocity of movement of a predetermined medium at the angle. A training line is generated at the angle of the scan lines, the training line being utilized to determine portions of the scan line which are in a flow medium of interest, such as blood, and portions of the scan line which are in clutter. Information from the training line is then utilized to control the gain of the scan lines so that the gain is substantially maximized when scan lines are in the flow medium, while being reduced so as not to saturate the system in general, and A/D converters in particular, when in clutter. When an image line is utilized in the system, this line may also function as the training line.

Abstract: A medical Doppler ultrasound imaging system with improved filtering to separate blood flow information from clutter due to heart wall and vessel motion. In combination with a clutter rejection filter and velocity determination system as in the prior art, a velocity sample rejection system implements a velocity-dependent (i.e., frequency-dependent) threshold for rejecting velocity values, or samples, based on too weak echoes. That is, the acceptance/rejection threshold is a function of frequency. Optimally, the shape of the velocity-dependent thresholding function closely matches that of the attenuation transfer function of the clutter rejection filter. Thuys, for low velocity samples (corresponding to low Doppler frequency shifts), the rejection threshold is substantially lower than it is for high velocity samples. The rejection level increases monotonically as the signal deviates from the I.F.

Abstract: Estimates of the average velocity and turbulence of blood flow are determined by weighting the instantaneous frequencies of a returning Doppler signal. The weighting can be chosen so that the estimates are optimized. The weighting can be chosen so as to duplicate the algorithm of other ultrasound flow imaging systems.

Abstract: Apparatus for controlling the amplitude of a signal applied to an FFT system in accordance with the overflows occurring in the various butterfly operations.

Abstract: Apparatus for interpolating data along radial lines so that it can be displayed at display points arranged in orthogonal rows and columns by recursively adding stored values to derive signals indicative of the radial position of each display point along the radial data lines and its angular position between the radial data lines. Interpolation is done along each radial line to derive first and second intermediate interpolated values, and these values are interpolated so as to derive the final data value for the display point at its angular position. Alternatively, the intermediate interpolated values can be attained by angular interpolation and the final data value by radial interpolation.

Abstract: Apparatus for displaying the information represented by data samples occurring along radial lines at display points arranged in rows and columns wherein intermediate interpolated data values are derived at the intersections of a row containing a display point for which a final data value is sought with radii on either side of the display point and interpolating the first and second intermediate interpolated data values so as to derive a final interpolated data value at the angular position of the display point with respect to the radii.