Abstract: An acoustic imaging apparatus and method that achieves desired delays with coded signals. Linear, curved linear and sector scanning is provided in 1-D arrays and planar, curved planar and sector scanning is provided in 2-D arrays. Composite and non-linear implementations are presented. Dynamic and discrete dynamic focusing is disclosed for the relevant arrays. The 2-D array makes possible 3-D imaging.

Abstract: An ultrasound imaging system enables 1.5D image information to be generated from a single firing of a linear transducer array by permitting dynamic control over the receive aperture. The imaging system comprises a transducer having a linear array of piezoelectric elements arranged in a plurality of distinct rows of the elements. The transducer is operable to provide acoustic pulses from elements of a first one of the rows in response to respective driving signals and to provide corresponding return signals in response thereto at elements of additional ones of the plurality of the rows and at the first one of the rows. A receiver is coupled to the transducer to receive a summed signal corresponding to the return signals from the elements. The receiver comprises a plurality of low voltage switches that couple to respective ones of the additional ones of the plurality of the rows, and a high voltage switch disposed in series with the low voltage switches.

Abstract: An array of ultrasonic transducers, where each of the ultrasonic transducers has a matching layer end and a driving layer/individually isolated end. A bump bond connects each one of the ultrasonic transducers to a substrate. A high voltage electrical conductor is connected to at least one driving layer/individually isolated end to provide a drive signal to at least one of the ultrasonic transducers. A conductive/matching layer is disposed to electrically connect each matching layer end. An outer matching layer is connected to the conductive/matching layer. The bump bond is an indium or solder bump bond having a contact area for contact with an ultrasonic transducer less than 20 percent of the driving layer/individually isolated end for the contacted ultrasonic transducer so as to provide mechanical stability while reducing cross talk among the plurality of ultrasonic transducers.

Abstract: An ultrasonic receive beamformer includes transducers forming receive signals that are applied to sub-array processors. Each sub-array processor includes at least one phase shifter and a summer, and each phase shifter is responsive to at least one of the transducer signals to shift the transducer signal by a respective phase angle and to apply the phase shifted transducer signals to the summer. Each of the summers supplies a summed sub-array signal to a respective beamformer processor. The phase angles for any one of the sub-array processors form a sum substantially equal to zero. Furthermore, the phase angles for any one of the sub-array processors are independent of the time delay of the respective digital beamformer processor. The time resolution of the time delay of the digital beamformer processors is substantially as fine as the time resolution of the phase angles of the phase shifters.

Abstract: An image display apparatus, which is used to display a plurality of images on one display image by carrying out a filtering operation, comprises a memory unit, a filter unit, a write control unit, a delay unit, and a switching unit. The write control unit controls the writing of the display data at a region having a specific address length between adjacent display-regions, when storing the display data into the memory unit. The filter unit applies a filtering operation to the display data read out from the memory unit along the display scanning direction, and the delay unit gives a different delay value to the display data output from the filter unit. The switching unit switches the display data having a different delay value output from the delay unit at a boundary line of the adjacent display-regions. Therefore, the length between the adjacent display-regions can be shortened, and an image having a preferable length between the adjacent display-regions without an intervention can be displayed.

Abstract: An acoustic imaging device for providing an image of a body in a medium, includes a plurality of acoustic transmit elements and a plurality of acoustic receive elements, an apparatus for activating one of the transmit elements to generate an ultrasonic signal, an apparatus to selectively receive and record from each of the receive elements a set of data representing a phase, amplitude and transit time of the ultrasonic signal, a first computing apparatus for calculating a velocity map of propagation velocity values in each of a plurality of volume elements including the body and the medium using the data set, and a second computing apparatus for calculating a reflectance map, including a coherent sum of reflectance values at selected points in the plurality of volume elements using the data set.

Abstract: An apparatus for generating the required beamforming delays for an ultrasound imaging system with minimal hardware and software. The apparatus performs an algorithm which allows the required computations to be separated into three groups. The first group includes transducer array geometry computations which are beam independent. The second group includes a small number of beam-dependent computations which are channel independent. The final group includes the channel- and beam-dependent calculations which combine the results of the first two groups to generate the required beamforming delays. This last computation is distributed to logic and simple real-time state machines per channel. This approach reduces the required computations and takes advantage of simple parallel processing to reduce the required hardware and computational time relative to conventional beamformer designs.

Abstract: In the present invention, a control system uses acoustic data produced by an ultrasound system to assess whether the acoustic environment presented to the ultrasound system's transducer is an imaging environment, such as patient's body, or a nonimaging environment, such as air. Various operating parameters of the ultrasound system may be controlled based on the assessment. In the nonimaging environment, the control system reduces the amplitude of a drive signal applied to the transducer, substantially reducing power dissipation in the transducer. The control system detects a transition to the imaging environment and returns the drive signal to the amplitude used in the previous imaging environment. If the nonimaging environment persists for greater than a predetermined time period, the control system initiates a standby mode which substantially reduces power consumption by the ultrasound system. The control system is readily integrated into the imaging stream of an ultrasound system.

Abstract: A system and a method for generating an ultrasound image of an interrogation region in an object with a transducer with a two-dimensional array of transducer elements, includes the steps of generating an ultrasound beam by activating many transducer elements of the two-dimensional array; electronically controlling the beam to illuminate substantially the same region from at least two orientations; capturing the echoes generated with the beam illuminating the object at different orientations; and analyzing the echoes from all directions to produce an image of the region of the object. The aperture of the transducer generating the beam is at least substantially equal to the aperture generated by a linear array of transducer elements extending across the substantially shortest distance between two opposite edges on the two-dimensional array. The ultrasound power emitted from the transducer elements is not spatially uniform, and the multiple echoes reduce speckle in the image.

Abstract: Apodization parameters for respective transducer elements are generated, for example, at a beam-former, by accessing a select look-up table. An apodization parameter generator circuit includes respective look-up tables for each of multiple window algorithms. The same look-up table is used for a given window algorithm regardless of (i) aperture size; (ii) whether performing transmit or receive beam-forming; and (iii) whether deriving elevation or azimuthal apodization parameters. Each of the multiple tables has a common, fixed number of entries. Such number is at least as big as the number of transducer elements along the longest axis of the host transducer array. For symmetrical tables, the number of entries is halved. A pointer into a look-up table is calculated from the elevational or azimuthal aperture size in elements ("N") and the location of the transducer element of interest ("n") along the aperture.

Abstract: The invention provides a method and system for estimating missing Doppler signals and spectra in an ultrasound imaging system: (1) parameters representative of a Doppler data model are matched to actual Doppler data that is received; (2) the parameters are interpolated or extrapolated (possibly after normalization, smoothing, or other manipulation) for regions where actual Doppler data is missing ("Doppler gaps"); and (3) a set of synthesized Doppler spectra are constructed, using the model and the interpolated or extrapolated parameters, for those Doppler gaps. The Doppler data model is an autoregressive model, or another model in which the Doppler data may be approximated by supplying a source signal to an autoregressive filter. The parameters of the model comprise a set of autoregressive filter coefficients and a .sigma..sup.2 (variance) value. The reflection coefficients of these autoregressive filter coefficients are determined. The reflection coefficients and .sigma..sup.

Abstract: An ultrasound ellipsoidal backprojection device includes a receiver element array with each element related to an image reconstruction point angle of a receiver apodizer, the apodizer having an apodization weighting amplitude function generator for weighting echoes received by the elements as a function of the image reconstruction point angle of thereceiver elements, and an ellipsoidal backprojection image reconstruction processor for reconstructing images from the weighted echoes.

Abstract: An ultrasound signal processor for receiving an ultrasound signal from a testing body by a plurality of electro-magnetic transducer elements and processing a plurality of received signals to obtain information of the interior of the testing body is provided with analog-digital converters for sampling at least two of received analog signals, multipliers for multiplying the outputs of the analog-digital converters by first complex digital reference signals, first low-pass filters for limiting the signal bands of the outputs of the multipliers, first complex multipliers for multiplying the outputs of the first low-pass filters by second complex digital reference signals, adders for performing the addition of the outputs of the first complex multipliers for real signals and the addition thereof for imaginary signals, memory devices for storing the outputs of the adders, second complex multipliers for multiplying signals read from the memory devices by third complex digital reference signals, and second low-pass f

Abstract: The invention includes a method and system for multiple transmit zone splicing in an ultrasound imaging system. Acoustic signals from a pair of adjacent transmit zones are crossfaded in a region where the two transmit zones overlap (an "overlap region"), to produce a set of combined acoustic signals that transition from one transmit zone to the next with little or no delineation between transmit zones. The crossfade is linear and for the entire overlap region; however, the crossfade may alternatively employ a nonlinear function, or may encompass regions near to the overlap region. When a scan line comprises more than two transmit zones, pairs of transmit zones are crossfaded, preferably at each overlap region. When overlap regions are close to each other, a crossfade employing more than two transmit zones may be employed, such as a linear crossfade in which acoustic signals from three or more transmit zones are weighted and summed.

Abstract: A method and an apparatus are provided for dynamic, real-time adaptive focusing for ultrasound imaging. Aberration delay correction values, corresponding to an aberration region in an imaged subject, are measured concurrently during B-mode imaging scan lines and updated at the scan line rate. The measured aberration delay correction values are then applied concurrently to correct the focus of all transmitted and received ultrasound scan lines, regardless of the imaging mode, scan geometry, or imaging frequencies.

Abstract: A method and a device for imaging an object using ultrasound. Transducer elements of a two-dimensional array are interconnected to form sub-arrays. The transducer elements of each sub-array are driven in the transmit mode with the same time delay and read out jointly in the receive mode. In this manner, the number of required time delays is reduced, and parasitic capacitances on the signal lines are diminished.

Abstract: 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.

Abstract: A phased array ultrasonic imaging system performs a scan in which beamforming time delay errors due to nonuniformity in ultrasound speed within the transmission medium are corrected by estimating and correcting phase aberrations in accordance with the maximum likelihood theory. The system employs a multiple-channel transmitter and receiver, and estimates phase values, not phase difference values, thereby eliminating any need to perform an integration to produce the phase aberration profile. The method can be implemented in real-time, allowing correct data to flow out of the circuit which at the same time can be receiving new input data. Delays can be added to allow for phase aberration correction of past measurements. The method allows tracking, to some extent, of variations that may occur in the phase aberrations. Depending on the number of channels that are simultaneously considered, different closed loop circuits can be employed.

Abstract: A method and an apparatus for increasing the apparent acoustic frame rate of ultrasound images. Frames of acoustic data are acquired at the acoustic frame rate, stored in double-buffered acoustic frame buffers and scan converted one after the other. For each pair of successive frames, the first acoustic frame is stored in a frame delay buffer while the other acoustic frame is being scan converted. In accordance with this scheme, the scan converter is always reading from an acoustic frame buffer that contains a single complete frame of acoustic data, thereby eliminating the swirl artifact. To increase the apparent acoustic frame rate, the scan-converted acoustic data is input to a scan-converted frame interpolator, which incorporates the frame delay buffer, a frame interpolator programmable read only memory (PROM) and a software-programmable inter-polator bank select look-up table.

Abstract: An ultrasonic diagnostic method and apparatus are provided for enhancing real-time performance, enlarging visual field, and improving S/N ratio without sacrificing any of real-time performance, visual field and S/N ratio by field into two or more sections; generating sounding waves forming a main lobe and grating lobes to scan the sections of the visual field respectively by the main lobe and the grating lobes; separately and directively processing an echo wave received along the direction of the main lobe and echo waves received along the directions of the grating lobes to form images of the sections separately; and combining the images of the sections to display an image of the visual field.

Abstract: A method and apparatus for controlling multiplexing of a transducer having more elements than the imaging system has receive channels. The active aperture is shifted in increments of a predetermined number of transducer elements, e.g., eight. While the active aperture is maintained constant for a predetermined number of vectors, the phase center of the vectors in the group is shifted so that offset is minimized. In the case wherein the active aperture is successively shifted by eight elements, the offset is varied between +4 and -4 during the interval between shifts of the active aperture.

Abstract: Elongated arrays of individual ultrasonic transducer elements at spaced locations emit wedge-shaped beams of ultrasonic energy such that energy emitted by corresponding elements of the arrays travels into a common region of the object to be imaged. Energy emitted by the elements of both arrays is reflected by the same structure within the object. The relative distances of the reflecting structure from the corresponding elements of the arrays are compared to determine the elevation of the reflecting points with respect to an image plane, and a three-dimensional image of the reflectors is generated. A virtual image including information responsive to the elevation of the points can be derived, and used to recalculate the visible display corresponding to a user-selected image plane. The transducer may include a parallel pair of arrays.

Abstract: An ultrasonic imaging system for performing a scan in which beamforming time delay errors due to nonuniformity in ultrasound propagation speed within the transmission medium are corrected. The system employs a multiple-channel transmitter and receiver. The method estimates and corrects phase aberrations in phased array imaging systems, taking into account additional information associated with array elements which are not necessarily adjacent to each other. The method uses Kalman filtering to obtain an estimate of the phase differences associated with complex samples of pairs of adjacent receive channels. The method incorporates a scheme to detect and correct for the 2.pi. phase slips that may occur in the data. Because the method provides information on measurement variances, better estimates are obtained by weighting the measurements according to their variances.

Abstract: An ultrasound imaging system is provided which produces gray scale images of the anatomy simultaneous with Doppler signal processing so as to provide a single real-time image that shows not only the vascular anatomy and surrounding tissue but also flow events in the vascular compartment. A phased linear array having near-continuous focus over the scanning field provides high resolution and very small Doppler sample volumes. The system tests incoming signals from throughout the scanning field for amplitude, phase and frequency so as to determine B-mode data, motion presence and direction, and echo source velocity.

Abstract: An ultrasonic imaging system beamforming architecture comprises a fixed wideband preprocessor section followed by a reduced number of dynamically adjusted delay channels. The preprocessor includes a transform beamformer with spatial filtering followed by a delay beamformer. Each transform preprocessor provides transformation of the local array space data into beam space. One, or combinations, of these beams may then be selected as input signals to an inverse transform which converts the beam space data back into array space data. This re-establishes the spatial array, but with a reduced directional view, allowing an inverse transform of reduced size to be used for the reconstruction. The result is a decrease in the number of channels required by the remainder of the beamformer.

Abstract: A three dimensional object under test is measured to obtain shape data representing a shape of the three dimensional object. The object under test is measured using, for example, an ultrasonic probe LED to obtain defect test data. A processing mechanism forms a three-dimensional graphic image of a defect zone from the defect test data and a three-dimensional graphic image of the object under test from the shape data. A display mechanism is provided for displaying the three-dimensional graphic image of the defect zone superimposed over the three-dimensional graphic image of the object under test.

Abstract: A phased array digital ultrasound beamformer for use with an ultrasound transducer array. The beamformer includes a processing channel for each element of the transducer array. Each processing channel includes a digitizing circuit for converting the received signal to digital samples and a time multiplexed digital delay circuit responsive to delay coefficients for delaying the digital samples by time multiplexed delays to produce delayed, time multiplexed samples for forming two or more receive beams. The ultrasound beamformer further includes a summing circuit for summing the delayed, time multiplexed digital samples from each processing channel to form a stream of time multiplexed output samples that is simultaneously representative of two or more receive beams. A coefficient generator supplies the delay coefficients to the time multiplexed delay circuit in each of the processing channels.

Abstract: An ultrasound imaging system of the type including a 2D transducer array which has first and second types of transducer elements. Each element of the first type occupies an area of the array which is an integral fraction of the area occupied by each element of the second type. A connection arrangement comprising a plurality of multiplexer/summation circuits is provided for electrically connecting the array elements to the remainder of the ultrasound imaging system. Each multiplexer/summation circuit has a plurality of signal inputs individually connected to a respective plurality of the elements of the first type for selectively combining a given number of the elements of the first type together, the given number being an inverse of the integral fraction.

Abstract: The ultrasonic transducer (5) is moved along the axial direction of elements of elongate shape (1), and is electrically excited for the emission of ultrasonic waves. Electrical measurement currents originating from the transducer (5) are collected and analyzed. The transducer (5) comprises a support having a concave active surface having curved generatrices and a plurality of piezoelectric elements fixed to the active surface of the support in adjacent dispositions.

Abstract: A probe in an ultrasound imaging system uses electrostrictive transducer elements that exhibit little or no piezoelectric properties when in an unbiased state, but do exhibit them when a bias is applied. A linear array of a large number of electrostrictive transducer elements in a probe are provided with an aperture that is shifted across the probe by biasing on and off banks of interconnected electrostrictive transducer elements. The progression of transducer elements from one end of the probe to the other is divided or grouped into adjacent banks of consecutive transducer elements. Each bank has the same number (n) of transducer elements. Each of the n-many transducer elements within a bank has a bias terminal, a signal return or ground terminal and a driven terminal. All the ground terminals are common and connected to a signal return, or ground. The driven terminal of each transducer element in a bank is connected in parallel with the corresponding transducer element in every other bank.

Abstract: A technique for scanning an image field with adjacent beams of ultrasonic energy is provided in which initially transmitted beams are transmitted along beam directions down the center of the image field. Subsequent beams are alternately transmitted on either side of the initially transmitted beams and at increasing lateral locations in said field with respect to the locations of the initially transmitted beams until the full image field has been scanned. In a preferred embodiment a waiting period is added to the pulse repetition interval of each transmission to allow time for multipath reflections to dissipate. The waiting periods are longer during initial transmissions in the vicinity of the center of the image field, and decline as beams are transmitted at increasing lateral locations of the field. The scanning technique provides a reduction in multipath reflection artifacts while maintaining a smoothly varying or uniform temporal disparity in the transmission times of adjacent beams.

Abstract: In a method for obtaining temporal equity of multiple images for ultrasound imaging equipment, a vector set is determined for each of the multiple images, representative of vectors to be aligned. A plurality of independent weights is then calculated for each image based on the vector sets. The plurality of calculated independent weights is used to determine a firing sequence which provides temporal equity of the multiple images.

Abstract: In an ultrasonic diagnostic apparatus which uses at least part of an array of a plurality of ultrasonic vibrators as an aperture for ultrasonic beam formation, sends ultrasonic waves into an object, receives echoes from the object, delays the output echo signals of a plurality of vibrators participating in receiving the echoes by a given quantity, adds up the delayed echo signals for echo beam forming, and forms a picture of an internal structure of the object by using the signals obtained by echo beam forming, the echo beam forming is characterized by forming a plurality of partial apertures in an aperture of an array of ultrasonic vibrators, delaying the echo signals provided by groups of vibrators included in the plurality of partial apertures by a given quantity determined so that a plurality of echo beams having a common focal point are formed, adding up the delayed echo signals of each group, detecting the respective sums of the delayed echo signals of the groups, and adding up the respective detected s

Abstract: A method for reducing speckle artifact in an ultrasound image using a two-dimensional median filter having a diamond-shaped five-point kernel. The entire pixel image data is passed through the filter in a manner such that the center point of the kernel is effectively stepped down each range vector in sequence. The magnitudes of the pixel data at each of the five points in the kernel are compared and the value which has the middle magnitude is adopted as a new pixel value, which is substituted for the old pixel value at the center point. After a new filtered vector has been formed from the new pixel values produced at successive center points by stepping down one acoustic vector, the kernel is shifted by one vector and stepped down range again. This process continues through the entire set of vectors until a new set of filtered vectors is formed. This filter will remove speckle holes on the order of one pixel in size while preserving good edge definition.

Abstract: An acoustic imaging system includes pairs of variable gain amplifiers for deriving essentially pairs of signals from respective signals generated in respective ultrasonic vibrators and the pairs of signals are superimposed on each other in a time difference corresponding to a phase angle of .pi./2 in frequency of ultrasonic waves. Amplification factors of the variable gain amplifiers are controlled so that the desired phase shift of the superimposed signals is obtained to attain dynamic focusing. Another acoustic imaging system includes a switch circuit having a two stage matrix switches construction that performs matrix switch functions in a smaller number of switch elements. Still another acoustic imaging system includes constituents for the aforementioned phase control for fine adjustment of delay time, the aforementioned switch circuit for rough adjustment of delay time, and variable gain amplifiers that perform smooth switching of the delay time.

Abstract: Ultrasonic imaging apparatus and method are shown which include electronic correction of focus defects produced by acoustic refractive index inhomogeneities within an object (14) being imaged. The region of interest (38) within which focus correction takes place is selected by the operator using control (42 or 84). The imaging system includes adjustable time delays (28-l through 28-c) through which return signals from transducers (10-l through 10-n) pass. Outputs from the delays are summed (30) and the resultant signal is envelope detected (32). The envelope detector output is prepared for display at display (36) by scan converter (34). The output from a focus correction delay control circuit (64) is used to control delay times of individual delays (28-l through 28-c) to provide for a delay profile across operative elements of transducer array (10), which delay profile includes delay profile components that correspond to low order terms of a series expansion, such as a Fourier series (FIG. 4).

Abstract: An ultrasonic diagnostic apparatus including ultrasonic transducers. The ultrasonic diagnostic apparatus performs calculations for respective ultrasonic transducers to determine at which focal position a signal having just been received by the transducers is reflected in accordance with a lapse of time from a time when ultrasonic waves are transmitted. A delay time of respective received signals obtained from the transducers are determined in accordance with the results of the calculations. According to the present invention, control data which determines the delay time is stored in a first stored apparatus, compensation data which compensates the control data is stored in a second storage apparatus. The control data and compensation data read out respectively from these first and second storage apparatuses are added to one another, and the delay time for transmission and reception is determined according to the sum of the control data and compensation data.

Abstract: An ultrasonic diagnostic apparatus has a probe having a plurality of channels, a receiving circuit for dividing receiving signals from the probe to deliver them in the form of "K" (K being an integer which is 2 or more) blocks each having a predetermined number of channels, a selector circuit for selecting signals corresponding to respective ones of the blocks from output signals of the receiving circuit and delivering the selected signals, a signal distributor for selecting the output signals of the receiving circuit in the mode of single beam reception and selecting the output signals of the selector circuit in the mode of simultaneous parallel beam reception, "K" delay circuits connected to outputs of the signal distributor and each having the predetermined channels, and a switch for switching the "K" delay circuits to series connection in the mode of single beam reception and switching the "K" delay circuits to parallel connection in the mode of simultaneous parallel beam reception.

Abstract: The present invention relates to an improvement of a delay control circuit of an ultrasonic diagnostic apparatus and is intended to provide a circuit configuration capable of utilizing a cyclicity of combination of signal lines, to absorb variations of a delay amount in accordance with a probe frequency by changing over a plurality of input ports corresponding to the frequencies of the probe which are provided for each of partial assemblies (delay control blocks) of delay lines at an input part of each assembly (delay control block), to confine crossings of signal lines within the partial assemblies of delay lines (delay control blocks) and to allow connection between partial assemblies of delay lines (delay control blocks) with a single signal line.

Abstract: A low cost phased array sonic transducer is described in which an array of transducer elements separated by spacers are held within a frame which applies a compressive force transverse the length of the elements.

Abstract: A frequency transfer type phase adjustment apparatus for frequency-transferring a plurality of reception signals derived from arrayed ultrasonic transducer elements into low frequency components by mixing these reception signals with a reference signal, and for applying delays to these low frequency components so as to be summed with each other, comprises small delay circuits for applying very short delays to the respective reception signals before being frequency-transferred; and a quantizing delay circuit for applying delays obtained by multiplying a delay time unit by an integer, to the respective reception signals after being frequency-transferred. A ratio of the delay time unit to one-cycle period of the reference signal is equal to an integer ratio. Phase shifters are inserted into either the output sides or the input sides of the mixers for the respective signal channels used for the frequency transfer operation.

Abstract: A phase adjustment circuit for use in an ultrasonic apparatus which respectively time-adjusts a plurality of received signals from an ultrasonic transducer array and sets wave fronts of the reflected waves from particular positions into an in-phase state and adds the in-phase signals, thereby obtaining a received beam. The received signals are mixed with phase-controlled reference signals. The low frequency component of the mixed wave is sequentially sampled and stored in a memory which is controlled by a clock signal of a predetermined period, and thereafter, the stored sampled signals are read out. Most of the necessary time adjustment results from the difference between the writing time and the reading time. The remaining micro time adjustment is performed by phase control of the reference signals.

Abstract: An ultrasound transceiver providing enhanced imaging by selective filtering of the received signal to provide a variable frequency, constant bandwidth filtering of the received echo signals. The resulting signals are then detected to produce a signal, which when displayed, has a reduced number of false multiple images and enhanced signal quality from the deeper tissue discontinuities. Additionally, the received signal is detected in quadrature by reference to a simulated carrier pilot tone having a nonconstant frequency relationship to the transmitted signal The resulting signal is post-processed to provide information which is used to display structural features, and in addition, the velocity profile of blood flow. The structure and velocity image information is superimposed to provide a composite signal wherein the static and dynamic characteristic of a patient is completely reported to the observer.

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 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.

Abstract: In ultrasonotomography, ultrasonic transducers are divided in the scanning direction and in a direction (elevation direction) orthogonal to the scanning direction and by changing the aperture in the elevation direction through focus in elevation direction, a tomogram and a Doppler signal of a blood flow can be obtained and displayed two-dimensionally. Doppler data is obtained by effecting slight angle scan of the ultrasonic beam mechanically or electronically in the elevation direction. Data pieces for the same raster of a plurality of Doppler data pieces obtained through the slight angle scan in the elevation direction are added/averaged or added to improve the S/N ration. By effecting the slight angle scan of the ultrasonic beam in the elevation direction orthogonal to a tomogram plane, a vessel at a position deviant form the tomogram plane can be found.

Abstract: A real time 3D medical ultrasound imaging machine is disclosed. Large extended transmitters are used with a great range of different pulse types, giving improved signal to noise ratio. Image reconstruction is done by filtered ellipsoidal backprojection. The filter is an inverse triplet filter. Sparse arrays may be used. The imaging machine additionally promises higher resolution, greater sensitivity 2D real time images displayed simultaneously with the real time 3D image.

Abstract: The present invention relates to an acoustic microscope system having an ultrasonic probe that is driven with a high-frequency burst signal to radiate an ultrasonic signal and that detects the resulting reflected and irradiated waves, a Z-axis moving device that updates the vertical distance Z between the probe and a material of interest for each sampling position, and device for constructing a V(z) curve from the reflection signals obtained at respective sampling positions. The ultrasonic probe of the invention is provided with an acoustic lens, a first ultrasonic transducer for receiving a leaky surface skimming compressional wave reflected from a sample material on one side of the acoustic lens, and a second ultrasonic transducer also provided on the side of the acoustic lens for receiving a leaky surface acoustic wave.

Abstract: In an ultrasonic diagnostic apparatus in which ultrasonic echo beams is focused three-dimensionally, a probe employs plural transducers arranged in two directions, lateral and azimuth directions. The transducers arranged in each azimuth direction are connected to a transmitting-receiving channel in a transmitting-receiving portion via a switch circuit. The switch circuit operates on the control of a switching controller and can connect a transducer selected by the controller in the azimuth direction to the transmitting-receiving channel. Output signals from the transmitting-receiving portion are supplied to a signal processing portion, in which beam forming for three-dimension echo beams is carried out by using a beam former. Thus, transducers arranged on each line in the lateral direction can be driven simultaneously, resulting in a more compact circuit and a reduced number of transmitting and receiving for better real-time processing.

Abstract: A three-dimensional imaging system for obtaining a three-dimensional image of an object being scanned ultrasonically comprises a source arrangement for sequentially transmitting ultrasonic energy toward the object in successive directions in a first scanning plane, followed by sequential transmission of ultrasonic energy toward the object in successive directions in successive scanning planes parallel to the first scanning plane, a detector arrangement for receiving reflected energy and converting the reflected energy to electrical signals, and a processor for processing the electrical signals to develop reconstructed image data of the object, the reconstructed image data comprising forward projections of the object into a left image plane and a right image plane to form left and right images, respectively, the left and right images forming a stereo pair for composite display by a display unit.