Abstract: Method for scanning a field of view using a scan format, wherein the carrier frequency of the imaging pulse is higher in the center of the field of view than at the edges. The frequency variation can be accomplished on transmit by modulating appropriately delayed programmable initial waveform information samples with a programmable carrier frequency. This results in a pulse transmitted into the body whose frequency is highest in the center portion of the scan, and is reduced in a controlled fashion as the steering angle is increased in order to mitigate grating lobe artifacts. The technique preserves signal energy because modulation merely translates the signal in frequency substantially without modification of the pulse shape itself.

Abstract: An acoustic scanning method and apparatus implemented by transmitting ultrasonic pressure waves and receiving return echoes on a set of spatially non-overlapping acoustic lines scanned along a transducer array with the active acoustic lines shifted and steered so that each acoustic line originates at an arbitrary point on and at an arbitrary angle to the face of the array. In a preferred embodiment, an extension of each acoustic line may also pass through a substantially common vertex that is not on the face of the transducer array, but preferably behind it a selectable distance to provide an extended field of view. The extended field-of-view is defined by the selectively variable location of the common vertex of the acoustic lines and the physical ends of the array, may use the entire transducer array in the near-field, has high quality resolution in both near and far fields, and may simultaneously transmit and receive two or more ultrasound beams from the same transducer aperture.

Abstract: An acoustic scanning method and apparatus implemented by transmitting ultrasonic pressure waves and receiving return echoes on a set of spatially non-overlapping acoustic lines scanned along a curved linear transducer array with the active acoustic lines shifted and steered so that each acoustic line originates at an arbitrary point on and at an arbitrary angle to the face of the array. In a preferred embodiment, an extension of each acoustic line may also pass through a substantially common vertex that is a selectable distance behind the array to provide a field-of-view defined by the selectively variable location of the common vertex and the physical ends of the array, may use the entire transducer array in the near-field, has high quality resolution in both near and far fields, and may simultaneously transmit and receive two or more ultrasound beams from the same transducer aperture.

Abstract: A dual mode color Doppler imaging system using a linear array of transducer elements generates and transmits into an organism, such as the human body, an acoustic imaging beam optimized for B-mode imaging and a separate acoustic Doppler beam which is steered at preselected angles relative to the imaging beam and is optimized for Doppler data acquisition. Acoustic imaging echos are acquired and displayed as a B-mode gray-scale image. Doppler data are acquired from multiple sample volumes along the direction of each Doppler beam. The Doppler information acquired along multiple lines is displayed as a color-encoded image that is spatially coordinated with, superimposed upon and simultaneously displayed with, the B-mode gray-scale image.

Abstract: An acoustic scanning method and apparatus implemented by transmitting ultrasonic pressure waves and receiving return echoes on a set of spatially non-overlapping acoustic lines scanned along a transducer array with the active acoustic lines shifted and steered so that each acoustic line originates at an arbitrary point on and at an arbitrary angle to the face of the array. In a preferred embodiment, an extension of each acoustic line may also pass through a substantially common vertex that is not on the face of the transducer array, but preferably behind it a selectable distance to provide an extended field of view. The extended field-of-view is defined by the selectively variable location of the common vertex of the acoustic lines and the physical ends of the array, may use the entire transducer array in the near-field, has high quality resolution in both near and far fields, and may simultaneously transmit and receive two or more ultrasound beams from the same transducer aperture.

Abstract: A dual mode color Doppler imaging system using a linear array of transducer elements generates and transmits into an organism, such as the human body, an acoustic imaging beam optimized for B-mode imaging and a separate acoustic Doppler beam which is steered at preselected angles relative to the imaging beam and is optimized for Doppler data acquisition. Acoustic imaging echoes are acquired and displayed as a B-mode gray-scale image. Doppler data are acquired from multiple sample volumes along the direction of each Doppler beam. The Doppler information acquired along multiple lines is displayed as a color-encoded image that is spatially coordinated with, superimposed upon and simultaneously displayed with, the B-mode gray-scale image.

Abstract: An acoustic imaging system having an array of N transducers arranged for transducing transmit electrical signals into acoustic pulses and for transducing acoustic pulse echos into electrical receive signals has a transducer multiplexer that connects in substantially cyclic order any one of a selected group of M adjacent transducer elements to one of a plurality of substantially identical transmit or receive channels. Each channel includes phase changing means for dynamic focusing, such as a mixer driven by one of a plurality of individually phased clocks. A control demultiplier orders connection of an appropriate one of the differently phased clocks to the mixer of each channel in an order precisely corresponding to the cyclic ordering of the transducer connections by the transducer multiplexer as groups of M adjacent transducer elements are selected to form acoustic scan lines stepped across the entire array.

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.