Abstract: The present invention relates to an ultrasonic synthetic aperture diagnostic apparatus which detects information concerning an internal structure of an object to be examined by making each of a plurality of arranged transducers sequentially emits an ultrasonic pulse signal into the object in turn, receiving each ultrasonic echo reflected by the internal structure of the object by the plurality of transducers in each ultrasonic scanning cycle, and obtaining information concerning the internal structure of the object on the basis of input signals provided by the plurality of transducers. The present invention is intended to provide an ultrasonic synthetic aperture diagnostic apparatus capable operating at a high frame rate and of forming a clear picture of high quality even if the object is moving.

Abstract: A non-destructive, non-invasive arrangement is provided for detecting defects, such as voids, or poorly adhering layers in solid objects and laminated materials. A sensing signal is emitted by one transducer and received by two others. All of the sensors are disposed in a housing unit. The difference between the received signals is used to indicate a defect in the work piece proximate one of the transducers.

Abstract: An ultrasonic inspection system uses a submerged ultrasonic transducer to provide an ultrasonic beam focused to a small spot on a submerged surface of a member to be internally inspected. By use of a focused beam projected through a fluid, such as water, to a submerged surface, the ultrasonic energy is efficiently coupled to a surface area which may be small and/or of irregular or curved shape. Systems and methods for inspecting turbine rotor blade tenons permit a turbine rotor with hundreds of blades to be rotated past a submerged transducer with automatic recording and processing of ultrasonic echoes to develop two-dimensional color images of internal portions of tenons at which cracks may typically occur. Automated adjustment of beam focusing of a transducer including an array of elements and threshold monitoring of fault-indicative echo returns are provided for.

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: The present invention provides a medical ultrasonic imaging device with dynamic focusing that is capable of operating at high frequencies and providing high resolution. One embodiment of the device includes a plurality of transducers, arranged in either a linear or curved array, for converting an ultrasonic signal received by the device into a plurality of electrical signals. This embodiment of the device also includes a plurality of vector modulators for phase-shifting the plurality of electrical signals to achieve fine focusing. A delay line array is further included in the device that allows each of the phase-shifted electrical signals to be delayed by a selected amount to achieve coarse focusing of the electrical signals. Further included in the device is a summer of summing the time delayed and phase-shifted electrical signals to provide focused image data.

Abstract: Apparatus and method for compensating for differences in time at which an incoming acoustic wave is received by an array of acoustic signal receivers to take account of the shape of the incoming wave and the non-zero incidence angle of its approach. Each receiver is provided with a time delay module that introduces a large or coarse scale time delay .DELTA.t.sub.L plus a small or fine scale time delay .DELTA.t.sub.S, where .DELTA.t.sub.L is an integral multiple of a coarse scale time interval length .DELTA.t.sub.c and .DELTA.t.sub.S may be varied continuously from 0 to a predetermined time interval length (.DELTA.t.sub.S).sub.max that may be made at least as large as .DELTA.t.sub.c.

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: 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 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: An ultrasonic imaging apparatus for obtaining a tomogram image of an object to be diagnosed on a monitor includes electroacoustic transducers, a phasing unit, a phase detection unit, and an adding unit. The electroacoustic transducers are positioned in aligned relationship along a surface of the object, emit ultrasonic waves which penetrate the object, detect the ultrasonic waves reflected from the object and convert the reflected and detected waves to electrical detection signals. A phasing unit is connected to the electroacoustic transducers and receives the detection signals, delays them in accordance with delay amounts previously set therein and determined in accordance with the respective distances between the electroacoustic transducers and the object, and phase adjusts same to produce phase-matched detection signals.

Abstract: A phased array sector scanning (PASS) ultrasonic imaging system produces a fixed focus, steered transmit beam with an array of transducer elements. A receiver forms the echo signals received from an ultrasonic energy reflecting object at the array elements into a receive beam steered in the same direction as the transmit beam and dynamically focused. A midprocessor in the receiver makes corrections to the receive beam samples to offset errors caused by the transmit beam being out of focus at all but its fixed focal range.

Abstract: A PASS ultrasonic system includes a receive channel for each element in an ultrasonic transducer array which imparts a delay to the echo signal produced by each element. The delayed echo signals are summed to form a steered and dynamically focused receive beam. Each receive channel is formed as an integrated circuit. The integrated circuit calculates the required time delay for dynamic focussing in the receive channel as a function both of elapsed time in unit increments related to unit phase rotation increments of the carrier frequency and of previously calculated time delay values, in order to control a phase rotator and delay FIFO in the receive channel to implement echo signal delay control.

Abstract: Disclosed is an ultrasonic receiving apparatus for use with an ultrasonic diagnosis system, the apparatus containing digital delaying means and/or digital adding means. The delaying means provides delays of sufficiently high accuracy using a clock signal of a reasonably high repeat frequency on a reasonable scale of circuit construction, while the adding means allows for larger probe aperture.(1) The delaying means has delay circuits each offering a delay in units of the clock signal cycle, and infinitesimal delaying circuits each multiplying two signals derived from a single reception signal, one of the two signals being delayed relative to the other before the two are added.

Abstract: An ultrasonic imaging apparatus for obtaining a tomogram image of an object to be diagnosed on a monitor is provided. The apparatus includes electroacoustic transducers, a phasing unit, a phase detection unit, a reference signal generating unit, and an adding unit. Electroacoustic transducers are provided in a lie along a surface of the object, emit ultrasonic waves to the object, detect the ultrasonic waves reflected therefrom, and convert them to electric signals as detection signals; a phasing unit is operatively connected to the electroacoustic transducers for receiving the detection signals, delaying them in accordance with distance between the electroacoustic transducers and the object, and phasing them to match the phase of detection signals.

Abstract: A beam former in a PASS ultrasonic imaging system includes a set of sigma-delta modulators which operate to separately digitize the received echo signal from each transducer element. The oversampled one-bit digital representations of each echo signal are delayed as required for beam steering and focusing, and are summed together. A decimator filter reduces the sample rate of the digitized receive beam prior to display of the image resulting from the receive beam.

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: An ultrasonic search system comprises a hollow nozzle block including a plurality of radial nozzle openings, and a probe holder disposed in coaxial relation to the nozzle block and cooperating with the nozzle block to define an annular passage therebetween. A plurality of probes are mounted within the probe holder in radial alignment with the nozzle openings and extend radially from the inner surface of the probe holder toward the nozzle openings, respectively. Water is supplied to the annular passage and injected from the nozzle openings to a test piece of a circular section such as a steel pipe. The test piece passes through the hollow nozzle block while the nozzle block and the probe holder are rotated by an electric motor. Ultrasonic waves are transmitted from the probes through the nozzle openings into the test piece so as to detect flaws in the test piece by reflections.

Abstract: The object of the invention is a device for ultrasonic inspection of cylindrical objects. A transmitting ultrasonic transducer generates ultrasonic waves that are acoustically irradiated into the respective object via a coupling medium. At least three ultrasonic transducers are arranged in a row next to one another along a line. The outer ultrasonic transducers are receiving ultrasonic transducers. The other ultrasonic transducers are transmitting or transmitting/receiving ultrasonic transducers. The line is inclined against the longitudinal axis of the object by an angle which is between 0.degree.and 45.degree..

Abstract: A method and device for imaging three dimensions with a single pulse of energy is described. An embodiment is disclosed which uses a single monopolar transmitted pulse which radiates through a wide solid angular volume. Echoes caused by objects in this volume are detected by a large diameter, sparse circular array of receiver elements. The time history of each element is stored in a digital memory. A reconstruction processor uses this stored time history to reconstruct an image of the reflecting objects. A simple time of flight algorithm, based on Huygens principle, is used in the reconstruction. The algorithm automatically takes into account transmitted wave front curvature and makes no approximations such as fresnel or fraunhofer in the reconstruction. A circular array of receiver elements can be used, which is axicon, and is focused throughout the imaged volume. A perspective processor controls the reconstruction processor such that the volumetric image may be viewed from various perspectives.

Abstract: An ultrasonic diagnostic device according to the present invention in which a driving mechanism for driving vibrators in an opening port for the transmission of ultrasonic waves with weighting can be the one of low cost and low heat loss is characterized in that a plurality of driving signals for driving a plurality of vibrators in an opening port for the transmission of ultrasonic waves are made to have different waveforms from each other for weighting.

Abstract: This invention provides an ultrasonic transducer probe for medical scanning and a lens assembly for use therein. The probe has a housing in which an ultrasonic transducer array is mounted, there being an opening in the housing adjacent the transducer array. A first lens subassembly is mounted to the transducer and moves therewith if the transducer is rotated. A second lens subassembly is mounted to the housing to fill the opening therein, and includes, for example, a thin plastic film covering the opening and bonded to the housing to seal the opening and a film backing lens or layer. The first lens subassembly is preferably a compound lens. The lens subassemblies are formed of materials having relative acoustic properties, and having mating surfaces which are shaped, to selectively focus ultrasonic signals from the transducers.

Abstract: An ultrasonic diagnostic imaging system is provided for scanning with a linear transducer array and displaying an image area which is truncated with respect to a conventional triangular image sector to take the form of a trapezoid. Uniformity of image resolution and ease of signal processing enhancement is provided by transmitting adjacent ultrasonic beams at equal angular increments over the sector area. The ultrasonic beams transmitted are focused around predetermined transmit focal points and the transmit aperture employed for each transmission is determined by a transducer sensitivity criterion applied to the focal point. Means are provided for delaying signal components received from the beam directions so that the sum of the components will form a coherent echo signal.

Abstract: A method for generating an ultrasound image of a plane of a section of an examination subject having a non-uniform speed of sound distribution near the surface of the subject includes the steps of scanning the section plane line-by-line with a transducer array in an adaption phase and calculating values from the received, focussed echo signals which deviate from anticipated values which would arise given a uniform speed of sound distribution, the calculation being undertaken by a cross-correlation function of neighboring elementary transducers. Correction values are formed from the deviating values depending on the angle of incidence of the echo signals on the elementary transducers. In an imaging phase following the adaption phase, the delay values for focussing are modified dependent on the incident angle of the echo signals and dependent on the correction values for this incident angle.

Abstract: A method and device for imaging three dimensions with a single pulse of energy is described. An embodiment is disclosed which uses a single monopolar transmitted pulse which radiates through a wide solid angular volume. Echoes caused by objects in this volume are detected by a large diameter, sparse circular array of receiver elements. The time history of each element is stored in a digital memory. A reconstruction processor uses this stored time history to reconstruct an image of the reflecting objects. A simple time of flight algorithm, based on Huygens principle, is used in the reconstruction. The algorithm automatically takes into account transmitted wave front curvature and makes no approximations such as fresnel or fraunhofer in the reconstruction. A circular array of receiver elements can be used, which is axicon, and is focused throughout the imaged volume. A perspective processor controls the reconstruction processor such that the volumetric image may be viewed from various perspectives.

Abstract: An ultrasonic echography apparatus, comprising a device for forming M channels which comprises, for each channel an analog-to-digital converter a delay line for introducing a delay with a step of 1/f.sub.e, and a circuit for interpolation and selection from N samples for each input sample, which circuit is formed by:N parallel processing chains (j=1, . . . , N), N-1 of the chains comprising a respective digital filter for interpolation with a shift j/Nf.sub.e with respect to the non-interpolated signal of the N.sup.th chain, the N.sup.th chain comprising a compensation delay line to compensate for the delay introduced by the interpolation filter,and a multiplexer (422.sub.i) for the N parallel chains.

Abstract: An ultrasonic imaging apparatus comprises an ultrasonic transducer for propagating ultrasonic beams to a subject, and converting echo beams reflected from the subject into an echo signal, a focus switch circuit for setting a plurality of focal depths, and a focus control circuit for outputting delay signals corresponding to the focal depths set by the focus switch circuit. The focus control circuit changes the delay signals corresponding to the preset focus depths to signals corresponding to the focus depths that are located within a display range, especially when the ultrasonic image is enlarged and shifted with at least one of the preset focus depths out of the display range.

Abstract: So as to control parts of any form, such as panels made of a composite material, a control head (10) is used comprising a small bar made of an elastic material, aligned ultrasonic transducers (18) being placed in said control head which functions by reflected light. The small bar bears contact blocks (22,24) which are brought into support on the surface of the part to be controlled, which has the effect of deforming the small bar and orientating each of the transducers perpendicular to the surface. As regards parts having a non-uniform shape, a uniform quality of the control is thus ensured, the same applying for a reduction of the control time. A precise control of the evolution of the structure of parts during production is also rendered possible. Advantageously, the transducers are mounted on the small bar so as to be disassembled, said mounting being effected by means of wedging members, such as screws and metal wire clips.

Abstract: An ultrasonic flaw inspecting apparatus is provided in which the transmission signals comprising N number of the binary code sequences having sharp autocorrelation functions are input to an object to be inspected by a single transducer for transmission and the reflected signals are received by N number of transducers for reception. The N number of transducers for reception are connected and placed over each other so that the direction of respective polarization is inverted in terms of the time order of the binary code of the sequence.

Abstract: A quality assurance inspection system utilizes a plurality of ultrasonic transducers to probe an elongated tube for both dimensional and structural integrity. The transducers are pulsed in rapid succession, and echo signals are conducted over separate RF channels and through a multiplexor to a lesser number of detector signals channels, each including a discriminator. Inspection windows are opened in these discriminators to permit detection of echo signals and the generation of time mark signals for stopping a plurality of clocks which then register pulse-echo time intervals. These data are computer processed to provide tube dimension and flaw information.

Abstract: An ultrasonic imaging system has a probe with an even-numbered plurality of N of transducer elements, with one transducer element being present in each of a like plurality N of signal-processing channels, and with successive ones of the transducers polarized in alternating directions. The transducers require channel excitation drive signals which are either a positive-polarity pulse or a negative-polarity pulse, with signal polarity being dependent upon the polarity of the transducer in the particular channel. The processed outputs of each odd channel is connected directly to an associated input of a coherent summer while the processed output of each even channel is individually amplitude-inverted before connection to an associated summer of input. The summation means output is the sum of all channel transducer outputs, with suppression of any common-mode signal appearing anywhere in the system channels, from the transducer to the summation means inputs.

Abstract: An ultrasonic diagnostic apparatus which has a probe including a plurality of transducer elements made of an electrostrictive material arranged on a plane in two-dimensional directions, a bias applying unit for selecting the transducer elements in an arbitrary row in the horizontal direction to be in an operative condition by applying the same with a bias voltage, and a switching unit for selecting the transducer elements in at least one arbitrary column in the vertical direction by applying the same with a bias voltage, and controls the bias voltage applying unit and the switching unit to scan an ultrasonic beam in the two-dimensional directions to collect three-dimensional information on a body under inspection.

Abstract: According to the present invention, a cursor is displayed on a screen of display of an ultrasonic image obtained by scanning the surface of an inspection object by use of a probe formed by arrangement of array elements and, further, the cursor is moved to a desired position of the ultrasonic image so that ultrasonic waves are emitted to a position of the surface of the object corresponding to the aforementioned position and the reflection wave signals are displayed in another display portion. Accordingly, not only ultrasonic flaw detection (C-scope) in a plane of the object can be conducted, but also ultrasonic flaw detection (B-scope) in the direction of depth in a desired position of the object can be conducted simultaneously. Consequently, detailed flaw information, such as a flaw type, a flaw position, a flaw size and a flaw shape, in the object can be detected quickly.

Abstract: A method and device for imaging three dimensions with a single pulse of energy is described. An embodiment is disclosed which uses a single monopolar transmitted pulse which radiates through a wide solid angular volume. Echoes caused by objects in this volume are detected by a large diameter, sparse circular array of receiver elements. The time history of each element is stored in a digital memory. A reconstruction processor uses this stored time history to reconstruct an image of the reflecting objects. A simple time of flight algorithm, based on Huygens principle, is used in the reconstruction. The algorithm automatically takes into account transmitted wave front curvature and makes no approximations such as fresnel or fraunhofer in the reconstruction. A circular array of receiver elements can be used, which is axicon, and is focused throughout the imaged volume.A perspective processor controls the reconstruction processor such that the volumetric image may be viewed from various perspectives.

Abstract: In the ultrasonic imaging apparatus according to the present invention, ultrasonic transducers provided in a probe for corresponding channels are driven and caused to propagate ultrasonic waves by a standard signal generating circuit, transmission delay circuits and pulsers. Then, receiving signals obtained from the ultrasonic transducers are delayed in an analog manner by analog delay circuits. The resulting delayed signals are A/D converted by analog/digital converters. The outputs of the A/D converters are delayed in a digital manner by digital delay circuits composed of semiconductor memory elements. The resulting delayed outputs are summed by a summing circuit. The output of the summing circuit is detected. Predetermined imaging data is produced based on the detected output and displayed. In order to enhance delay precision of the analog/digital converters and digital delay circuits, the delay amount of the analog delay circuits can be continuously varied in small steps.

Abstract: A method for imaging a sample with a beam of vibratory energy from an array of transducers excites the array with successive ones of a plurality M of coded excitation signal sets with each set occurring in a different one of successive excitation time intervals. Each different set has signals with a different code. An excitation beam, produced by the array, is focused into the sample at successively smaller distances, along a selected ray path from the array, during each successive excitation time interval. A reception beam is focused along the ray path at successively greater distances from a minimum distance away from the array during each successive one of a like plurality of reception time intervals, for receiving, during each reception time interval, return response signals reflected from the sample.

Abstract: On emission and/or on reception, circuits impose on the signals emitted and/or received, delays in accordance with a random or pseudo-random delay law. On emission, just as on reception, this delay law is superposed on that for focusing and angulation of the signals. On emission, the law is obtained, for example, by causing variation of the instants of triggering of the generators of signals for the excitation of the transducers. On reception, either parallel random delay lines or conditional inversion circuits are included. These circuits permit the breakdown of the coherence of the ultrasonic waves on emission, on reception, or on both simultaneously, may be used in an analogue version, as well as in a digital version.

Abstract: A method and device for imaging three dimensions with a single pulse of energy is described. An embodiment is disclosed which uses a single monopolar transmitted pulse which radiates through a wide solid angular volume. Echoes caused by objects in this volume are detected by a large diameter, sparse circular array of receiver elements. The time history of each element is stored in a digital memory. A reconstruction processor uses this stored time history to reconstruct an image of the reflecting objects. A simple time of flight algorithm, based on Huygens principle, is used in the reconstruction. The algorithm automatically takes into account transmitted wave front curvature and makes no approximations such as fresnel or fraunhofer in the reconstruction. A circular array of receiver elements can be used, which is axicon, and is focused throughout the imaged volume. A perspective processor controls the reconstruction processor such that the volumetric image may be viewed from various perspectives.

Abstract: An improved annular array sensor [10] that facilitates hermetic sealing and uses optimum acoustic matching layers is disclosed. The key to the performance improvement obtained in the present invention is the method of forming the annular elements [38,40] of the array. In one approach, the elements [38,40] are not quite separated from one another at the concave side [14] of the sensor shell [12]. A series of cuts [34] are made into a shell [12] of piezoelectric material from its convex side [16]. These cuts [34] are made almost entirely through the shell [12] so that a small amount of material [20] remains between the cut and the concave side [14]. After poling, the resulting ultrasonic sensor [10] has the basic electrical properties of a conventional sensor in which the cuts are made completely through the shell [12]. However, the continuous concave side [14] of the ultrasonic sensor [10] need not be sealed.

Abstract: An elastic pulse generator including a piezo-electric or magnetrostrictive transducer which is focussing or associated with a focussing device, having a plurality of elementary emitting surfaces generating elastic signals. These signals are superimposed, after propagation over a certain distance, in a focal region. Several groups of elementary emitting surfaces are periodically exciting at a predetermined rate with respective separate electric signals. The emitting surfaces belong to transducer elements electrically isolated from each other and having different transfer functions. Delay lines are provided for phase shifting the elastic signals emitted by the transducer elements.

Abstract: A method for iterative phase conjugation adaptive reduction of phase aberration effects upon the time delays necessary for formation of a beam of coherent energy focused within non-homogeneous medium at a selected range R from, and at an angle .theta. with respect to the normal to, the surface of an array of a plurality N of transducers, each for providing a portion of the energy of the beam when excited and for converting energy reflected thereto to a signal therefrom, first bounces from a large collection of scatterers, contained in a portion of the medium to be investigated, a probe beam for that beam angle .theta.. The received signals from each of the (N-1) pairs of adjacent transducers are cross-correlated to drive a like number of phase conjugation correction signals, which are then arithmetically operated upon to provide a time correction for the time delay associated with each probe beam transducer, for that range R and angle .theta..

Abstract: An ultrasonic imaging system probe with an even-number of transducer elements, has a transformer for coupling the received signal from each transducer to an associated cable. The polling of the transformer primary windings are identical while the polling of the secondary windings of the transformer alternate, i.e. are reversed for all even-numbered channels, with respect to odd-numbered channels. All odd channel outputs are conected to a first signal bus, while all even channel outputs are connected to a second signal bus. The signal busses are connected to inputs of a differential-input amplifier, having an output which provides the sum of all channel transducer outputs, with suppression of any common-mode signal appearing in the system from the channel transformer secondary windings to the differential amplifier inputs.

Abstract: An ultrasonic imaging system for transmitting ultrasonic pulses into an object and detecting reflected ultrasonic waves therefrom. The system is provided with delay lines for real time imaging. The system comprises a probe means having a transmitting bundle of acoustic waveguides for transmitting ultrasonic pulses into an object. The transmitting bundle includes the delay lines which consists of having cladded acoustic waveguides of different lengths for introducing different delays in the ultrasonic pulses carried by each waveguide.

Abstract: A method for receiving a return signal from each of plurality M of different beam directions in media excited by a single excitation event, is to: assign each of the M directions to be substantially equally separated, by a small angular displacement from a central beam; excite the media with a single energy beam transmitted to be focused at the central beam; receive a return signal from the central beam; and for each of the M different beam directions, independently rotating the phase of the received return signal by an amount predetermined to displace the apparent focus of the response beam to the associated direction.

Abstract: Ultrasonic imaging is effected using a line focused transmitter 1 and a line focused receiver 3 arranged with their focal lines (f.sub.T, f.sub.R) crossing, and controlled such that the crossing point P of the focal lines scans a target to be imaged.

Abstract: A transmit focus generator circuit for pulsing an array of transducers in an ultrasound pulse echo imaging system for transmission of a focused beam of coherent ultrasound energy. A system clock is separated into eight phases. Focusing is achieved by controlling the clock phase delay and burst delay of transmission from each transducer element. Precalculated waveform parameters are stored in a system memory. For each line scan, registers in a transmit focus block for each transducer driver circuit are loaded with the waveform parameters. For each transducer element within the aperture for a particular line scan, the circuit controls the output of pulses to achieve a focused wavefront.

Abstract: An improved piezoelectric transducer permitting linear scanning along two intersecting planes. The transducer is fabricated from a cross shaped piezoelectric plate covered on both faces with metallic electrodes. First and second linear arrays are formed by the partial dicing of the opposite faces of the electrodes and plate. The two segments of the orthogonal arrays are integrated in the crossed area. An aperture may be disposed in the central area so as to permit a surgical implement, such as a biopsy needle, to be inserted into the tissue under ultrasonic visualization. Scanning electronics are alternately connectable to each of the arrays by means of a multiple pole switch under the control of a clock.

Abstract: An ultrasonic phased array imaging system is provided which includes a normal mode and an adaptive mode of operation. The adaptive mode adjusts the delay associated with each element in the transducer such that the average image brightness of the region of interest is maximized. A motion detector is provided for determining when the transducer has been moved a distance sufficient to render the previous adaptive measurements possibly invalid whereupon the system automatically reenters the normal mode. A method of operating the ultrasonic phased array imaging system is also provided.

Abstract: An apparatus for the inspection of a nuclear reactor fuel assembly in a water-filled pool having fuel rods with spaces therebetween includes an encapsulated housing having walls and being disposed in the water-filled pool. A lever drive mechanism is disposed in the housing. A rotary transmission connected to the lever drive mechanism extends through one of the walls of the housing toward the surface of water in the pool. A plurality of stationarily disposed lever linkages jut out from the rotary transmission outside the housing. Each of the lever linkages has an end facing away from the rotary transmission. Carriers are each connected to a respective one of the ends of the lever linkages. Probes are each disposed on a respective one of the carriers. Ultrasonic test heads are each disposed on a respective one of the probes for insertion into the spaces between the fuel rods.

Abstract: A robot positioning apparatus for use with robot devices having a movable portion, wherein the movable portion may be spatially oriented to, and controllably spaced from, a reference surface. Initial locating of the reference surface is accomplished by an approximate positioning subsystem using multiple, angularly oriented units which send and receive acoustic orientation positioning signals in search of the reference surface. Once a return signal is received, switching logic indentifies the necessary reorienting of the movable portion to achieve approximately the proper facing relationship of the movable portion to the surface. For precise positioning and ranging after the facing relation is established, a precision positioning subsystem emits an acoustic signal toward the surface, and a response signal is received back from the surface by at least two, and preferably three, receivers mounted upon the movable portion of the robot device.

Abstract: A system and method for measuring the acoustically induced vibrations within a living organism. The object is ensonified to set it into low frequency vibration. A continuous wave beam of ultrasonic energy is transmitted along one path and focused at the tissue to be investigated. A focused transducer receives the reflected beam along a second axis such that the intersection of the transmitted and received beams define a small, concentrated region positioned at the object under investigation. The received beam is phase modulated by the amplitude of vibration of the object producing sidebands whose amplitude can be ratioed to the amplitude of the high frequency peak to determine the absolute amplitude of the low frequency vibration.