Abstract: Ultrasonic apparatus and methods for detecting defects in a part include a plurality of transducer channels, at least one of which is dedicated to determining the thickness of the part. An initial thickness value is determined and stored, and then subsequent thickness estimates are compared to the original thickness value and, if the estimates bear a predetermined relationship with the stored thickness value, then the thickness estimates become the new thickness values.

Abstract: An echography probe wherein homogenization of the directivity of the points of the strip. The material constituting the strip possesses a coefficient of absorption which depends on the frequency. The profile of the strip is determined by the knowledge of the law of the variation of this coefficient of absorption as a function of the frequency. It is shown that the pattern of directivity of a probe fitted with a strip of this type is independent of the working frequency.The invention finds particular application in medical echography for tissue characterization.

Abstract: An ultrasonic imaging apparatus and method of forming an image of an acoustic image of an object employing the aperture synthesis technique, in which at least one partial aperture for accommodating a predetermined number of successive transducers is established and applied to a transducer array to select the predetermined number of successive transducers accommodated in the partial aperture so that the selected transducers serve to transmit ultrasonic acoustic signals to an object and receive signals reflected from the object, and the at least one partial aperture is specifically moved along the arrayed transducers for similar signal transmission to and/or signal reception from the object, whereby the apparatus and the method do not suffer substantial noise caused during changeover between transmitting and receiving operation modes and/or enjoy and enlarged aperture for signal transmission or enlarged aperture for signal reception with a suppressed decrease of the frame rate.

Abstract: Ultrasonic inspection apparatus includes a linear array of transmitting transducers and a linear array of receiving transducers providing TTU mode ultrasonic inspection. One to four transmitting transducers may be simultaneously pulsed as a group, and one to four receiving transducers may be simultaneously connected in common in a group by operation of a connection circuit. The connection circuit includes a plurality of multiplexor circuits having their signal inputs connected in common to respective receiving transducers and their address terminals connected to the data output terminals of programmable read only memory devices. Calibration means are provided for correcting the output signals produced by the receiving transducers to compensate for variations in the response of individual transducers.

Abstract: A dark field ultrasonic transducer is constructed with an outer annular spherical or conical transducer element and an inner spherical element. The outer annular element is excited and insonifies a small portion of a part surface near a discontinuity or crack with longitudinal waves or with surface waves. The inner dark field element is not focused to be sensitive to either reflected sound or waves reradiated from the surface waves, but detects sound scattered from surface discontinuities such as a crack edge. When surface waves strike a crack edge and restrike it after reflection from the bottom of the crack, two pulses are received and the time delay between them is a measure of crack depth. The crack shape and crack depth profile are determined as the part is scanned.

Abstract: An improved ultrasonic inspection system is provided which allows ultrasonic inspection to be performed using either of two ultrasonic frequencies and which also provides improved system sensitivity and dynamic range. In operation, the system produces two signals, one an amplified receive transducer signal and the other an attenuated receive transducer signal. Each signal is converted into a logarithmic representation. The two logarithmic representations are selectively provided to a read-only memory, which operates to output a signal corresponding to the receive transducer signal. Means are also provided which allows the system to use either of two ultrasonic frequencies.

Abstract: An ultrasonic inspection apparatus and method in which a linear array of acoustic transmitters and receivers are disposed adjacent to a workpiece, and alternating potential source is connected to some of the acoustic transmitters to project a side lobe of an acoustic wave toward a specific zone of the workpiece. Thereafter, the connections between some of the acoustic transmitters and the potential source are automatically changed, to move the specific zone as many times as may be necessary to provided scanning of the workpiece.

Abstract: An ultrasonic array having a number of juxtaposed transducer elements is used for imaging. The reception aperture of the array is divided into individual sub-arrays. Each of these sub-arrays receives, after emission of an ultrasonic signal correlated with it into the object, echo signals reflected therefrom. The echo signals received by the respective sub-array and which are reflected from a common focal point are added up to form a sum signal. For this purpose, at least for some of the transducer elements the delivered output signals are time-delayed according to given patterns. This procedure is repeated for various points along each scan line. The sequentially obtained sum signals are superimposed at each point of the scan line to form a received signal. With this line-oriented method, the same processing channels (time-delays) can be used several times, i.e. successively for each sub-array. This leads to cost-effective production.

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 Frensnel 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 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: An ultrasonic imaging apparatus comprises first and second ultrasonic transducers and a driver circuit for alternately driving the first and second ultrasonic transducers to transmit ultrasonic beams in directions crossing at a given target. A receiver fetches from the echo signals of the first and second ultrasonic transducers echo components corresponding to echoes reflected in the same direction as the ultrasonic transmission direction and at a predetermined angle with respect to the target. An arithmetic logic circuit processes the echo signal components to obtain an angular dependency of scattering. A monitor displays the information representing the angular dependency of scattering.

Abstract: This invention relates to an ultrasonic angle test probe comprising at least two ultrasonic transducers for respectively generating and receiving ultrasonic waves propagating in different directions. According to the invention, in order to obtain relatively small wedge shaped coupling members and small coupling surfaces on the side of the probe contacting the workpiece, a plurality of transducers are disposed above one another instead of side by side. In a typical embodiment, a first transducer is disposed on a first wedge-shaped coupling member and second transducer is disposed on a second wedge-shaped coupling member superposed upon said first coupling member for providing different angles of propagation of sound waves responsive to energizing one or the other transducer.

Abstract: Ultrasonic imaging equipment comprising ultrasonic transducers (A, B, etc.) which are sequentially and repetitively triggerable by equally spaced triggers (Z) to give echoes which can be read, stored and processed in a computer-based recording device is characterized in having means to inhibit the triggers under control of the recording device so that, after one transmission, further transmissions do not take place prior to the recording device reading the echo from said one transmission.

Abstract: A device for examining objects by ultrasonic echography comprising a focusing network of n ultrasonic transducers and in which the ultrasonic transducers (a,b,c, . . . i, . . . , n-1,n) are made of an electrostrictive material with non-remanent polarization, and the said polarization is effected by a polarization stage comprising: (1) a source (501) of p polarization direct voltages, (2) a demultiplexing and branching circuit (502) receiving, on the one hand, the p polarization voltages and, in the other, combinations of m bits selecting the said voltages in order to supply them to the transducers, (3) a circuit for the determination of a law of sensitivity (503), consisting of a counter (522) whose number of states corresponds at least to the numbers of directions to be explored and of a memory (521), intended to provide the n respective digital combinations corresponding to each state of the counter, and (4) a sequencer (520).

Abstract: A system for achieving inspecting and/or positioning of an object that includes: an array that is operable to generate acoustic or low-frequency electromagnetic wave energy of a single or narrow band of frequencies, to transmit the wave energy to an interaction region where it interacts with the object and to transmit the wave energy, after interaction, to sensing means, sensors of the array being disposed to receive the wave energy and being operable to convert the wave energy to electric signals representative of the received wave energy; a processor connected to receive the electric signal and adapted to process the signals into amplitude and/or phase information for each sensor; and an analyzer to interpret the amplitude and/or phase information to derive therefrom a characteristic of the object, e.g., a geometric characteristic or an electromagnetic characteristic.

Abstract: Method and system for detecting defects in the structure of a composite laminate material are described which comprise a first transducer for directing an ultrasonic beam of preselected frequency along a transmission axis onto a surface of the laminate at a preselected angle to generate Lamb waves in the laminate and leaky Lamb waves reflected therefrom; a second transducer for detecting the reflected leaky Lamb waves and for providing an output signal corresponding to the amplitude of the reflected waves; a fluid sonically coupling the laminate with the transducers; a positioning system for selectively positioning the transducers along the surface of the laminate to produce a set of output signals characterizing the laminate; and suitable electronics for receiving and processing the output signals and comparing them with signals characteristic of a defect free sample of the laminate.

Abstract: The invention combines a plurality of ultrasonic ranging transducers (11) arrayed proximate the end (12) of a movable robot arm (13), all transducers (11) being mounted to a common base so as to be pivotally movable both horizontally and vertically relative to the robot arm (13) by stepping motors (17 and 20). By controlling the pivotal movements of the transducer array (10) by a microcomputer (22) so as to look in the direction of intended travel of the robot arm end (13), and as to the robot arm end (13) moves, unexpected objects in the path of the robot (14) or aberrant motion by the robot (14) become easily detected. Upon the sensing of an obstruction to the direction of motion of the robot arm (13), or aberrant motion thereof, a signal from the microcomputer (22) to the robot (14) controls will halt further operation until the obstruction is removed or the problem corrected.

Abstract: An electronic scanning apparatus ultrasonic imaging adapted to converge or deflect an ultrasonic beam by controlling the amplitude and phase of the vibration of each transducer in a transducer array consisting of a plurality of regularly-arranged transducers, and adapted to move the ultrasonic beam by selecting from all of the transducers constituting the transducer array at least one transducer forming a transmitting and receiving aperture.

Abstract: An ultrasonic scanning apparatus includes a transducer array made up of a plurality of ultrasonic transducer elements and delay lines connected through individual switch elements to the transducer elements. The transducer array, the switch elements and the delay lines are each divided into two blocks. The ultrasonic echo signals derived from these blocks are summed through the corresponding delay lines. One of the summed signals of both the blocks is applied through a fixed delay line to an adder. The other of the signals is directly applied to the adder. The adder adds together these echo signals.

Abstract: The present invention is a multiline beamformer for use in a medical ultrasound scanner using a phased array transducer. Lines of ultrasound energy are generated having a pressure at the array aperture corresponding to sin (.pi.x)/.pi.x, where x is the normalized distance of the array element measured from the center of the array. This transmitted energy creates a flat field in space which can then be received in multiple receive lines, using bundled, parallel time delays.

Abstract: An ultrasonic inspection apparatus is shown for locating multiple defects in eccentric wall tubing or goods. A plurality of transducers are arranged in mated pairs, each of the pairs including a sender element for transmitting an ultrasonic shear wave and a receiver element for receiving a reflected ultrasonic wave component from the tubular goods being inspected. Each sender element is a point focus transducer having sufficiently high resolution to maintained detectability of defects in the tubular goods. Each receiver element is a wide focal width transducer having a large effective beam width area to compensate for eccentricity in the wall of the tubular goods.

Abstract: An ultrasonic testing method and apparatus stores the reflected ultrasonic signals from each of a plurality of locations along a scan path over a piece of material to be tested. For each individual location, the reflected signal at that location is added to contributing signals from each other location to produce a composite signal which has a good signal-to-noise ratio. The contributing signals from each other location is formed by multiplying the signal of those other locations by a corrective phase shift factor which is a characteristic of a time delay for a reflected signal from the other locations to the individual location of interest. The contributing signal from each other location thus represents a rotated reflected signal from the other locations.

Abstract: A method for the ultrasonic testing of bolts for incipient cracks emanating from a wall thickness discontinuity between thinner and thicker parts of the bolt, which includes placing an ultrasound transmitter and receiver in the form of a piezo-electric transducer on the periphery of the thicker part of the bolt with the discontinuity located in the near-field region, radiating longitudinal waves at an angle of 55.degree. to 70.degree. and transversal waves at an angle of 25.degree. to 35.degree. from the transducer in direction toward the discontinuity, and comparing the intensity of reflected transversal and longitudinal waves with an echo characteristic obtained from a test body corresponding to the bolt to be tested, having slots formed therein simulating incipient cracks of different depths, and an apparatus for carrying out the method.

Abstract: An ultrasonic transducer system is disclosed consisting of a support body (2), a radiating layer (8,9), a first .lambda./4 matching layer (10,11) and a second .lambda./4 matching layer (12,13). According to the invention, at least two ultrasonic transducers (4,6) with different and predetermined mid-frequencies are attached to a common support body (2) and have natural foci which overlap if the ultrasonic transducers (4,6) are mechanically separated. The ultrasonic transducer (4), having the higher mid-frequency, is provided with a larger radiating surface (4). This configuration, through the appropriate selection of the mid-frequencies, allows compensation for the frequency dependent damping of the transmission medium by frequency related weighting during radiation. In this manner, substantial improvements with respect to bandwidth of the total transmission path, from transmitting transducer through transmission media to receiving transducer, and the image quality can be realized.

Abstract: A method for evaluating echo signals transmitted and received by an ultrasonic transducer in a sensor of a movable mechanical element, such as an arm of an industrial robot, has the steps of receiving and storing the arriving echo signals in chronological sequence in a memory, the chronological sequence of the signal being converted into a corresponding sequence of memory positions, with successive sequences of echo signals of successive transmit pulses being stored in the same sequences of the memory positions. Integration of the echo signals of the successive sequences stored in the memory positions are undertaken such that the local shift of the ultrasonic transducer disposed on the moveable element which occurs between respective transmit pulses is compensated relative to chronologically adjacent pulses and the pulses reflected from a target are more easily identified.

Abstract: Sound heads (SK1 to SK3) are fixed, distributed peripherally, on the part of the body, e.g. an arm or leg. Each of the sound heads is able to transmit ultrasonic signals along a measuring section (MS1 to MS3) leading to another sound head, which signals are received by the other sound head. The sound heads can consist of angularly arranged sound members (14). In this way, all three sides of a polygon formed by the sound heads are measured, from which measurements the surface area of the polygon can be determined.

Abstract: A pulsating sound wave beam is transmitted into an object using an array-type ultrasonic wave transducer which consists of a plurality of elements; the reflected sound waves are received using said transducer while electronically focusing the reflected sound waves depending upon an estimated speed of sound in the object, and the beam width of sound waves is measured repeatedly near a particular reflector while successively changing the estimated speed of sound. The estimated speed of sound of when the beam width is minimal is the mean speed of sound of the object in practice, and the beam width at that moment serves as an indication of acoustical homogeneity of the object.

Abstract: In a transmitter section of ultrasonic imaging apparatus, a digital delay circuit is provided. The digital delay circuit includes a clock pulse selector for selecting one phase-shifted clock signal from the plurality of phase-shifted reference signal trains based upon delay time information of the control data signals of the timing control device, a clock counter for counting a pulse number of one phase-shifted clock signal derived from the clock pulse selector based upon the delay time information of the control data signals, thereby obtaining a digitally-delayed phase-shifted clock signal, and a wave number counter for counting a wave number of said digitally-delayed clock signal derived from said clock counter based upon wave number information of the control data signal, thereby finally obtaining a digitally-delayed phase-shifted signal having the desired wave number for the exciting phase.

Abstract: An ultrasonic flaw detecting technique in which reflection echoes of ultrasonic waves transmitted from a plurality of vibrator elements are received, and a composite signal obtained by composing the reception signals is supplied to a composite signal reception processing circuit. A method and an apparatus in which the existence of the composite signal is detected at a first time point at which the composite signal based on the reflection echoes from an inspection target in a main lobe can be detected and at a second and a third time point which are in advance of and later than the first time point respectively and at which the composite signal based on the reflection echoes from an inspection target in the main lobe can not be detected, so that when the existence of the composite signal is detected only at the first time point, it is determined that the composite signal is that based on the reflection echoes from the inspection target.

Abstract: The disclosure is directed to a method and apparatus for non-destructive inspection of a solid workpiece, such as a steel workpiece. In accordance with the method of the invention, ultrasound is generated at an annular ring or portion thereof and focused into a hollow substantially cone-shaped beam, or sector thereof. The beam is directed at the surface of the workpiece so as to establish shear mode ultrasound energy in the workpiece. Ultrasound energy is then received from the workpiece (e.g. by reflection or transmission) and characteristics of the internal structure of the workpiece can be determined from the received ultrasound energy. In the preferred embodiment of the invention, the beam is configured such that the ultrasound energy impinging on the surface of the workpiece is at a sufficiently large angle with respect to the normal to the surface such that primarily shear mode of ultrasonic energy will be established within the workpiece.

Abstract: Ultrasonic testing methods and units for characterizing planar flaws in hard-to-inspect materials such as welded and cladded pipes containing intergranular stress corrosion cracks. The invention characterizes flaws with pitch-catch transducers positioned front to back on a single module. One module uses a bimodal transducer to transmit longitudinal and shear waves to produce, through surface wave mode conversion, reflection and diffraction, a triplet of associated longitudinal and shear wave signals received by another bimodal transducer. Other modules use pitch-catch transducers to produce a doublet of associated shear wave signals from diffraction of an incident longitudinal and/or shear waves at the upper and lower extremities of underclad fatigue cracks and buried cracks. The signals are enchanced by multiple one sided cross focusing on preselected target areas in the test specimen and are cognizable by pattern recognition.

Abstract: Seismic exploration method and apparatus in which interference signals received by the sensing geophones from the seismic vibration source are cancelled by employing a signal representative of the seismic vibration source and combining it with the output from the sensing geophones.

Abstract: A transducer array and excitation circuitry for producing ultrasonic waves in a controlled pattern and for causing the waves to be scanned along the array. The array comprises a plurality of transducer elements coupled to each other in such a way as to produce a desired wave pattern when selected elements are activated. The array may be constructed from plural transducer elements or from a single plate of transducer material comprising a plurality of elements that can be individually activated, the plural elements being intercoupled to produce the desired wave pattern. The arrangement is such that a minimum number of electrical connections to the transducer elements are required to create the desired wave pattern and to scan that pattern across the face of the array.

Abstract: An ultrasonic non-destructive testing apparatus of the electronic scanning type comprising transmitter for producing exciting pulses in response to a predetermined timing pulse, a probe coupled to said transmitter, having a plurality of transducers for transmitting ultrasonic waves into a body to be tested and for receiving ultrasonic echo waves, signal processor coupled to said probe for processing said ultrasonic echo waves received by said probe to generate an echo wave signal, a memory coupled to said signal processor for storing reference data on an amplitude attenuation of an ultrasonic echo coming through each beam propagating path which is obtained by transmitting the ultrasonic waves into a calibration body at the time of a calibration, calculator coupled to said memory for calculating a predetermined correction value on the basis of said reference data stored in said memory, said predetermined correction value being at each crossing points on a two dimensional coordinate by applying a linear interpo

Abstract: An annular array ultrasonic transducer is provided which comprises a plurality of concentric rings of piezoelectric material having widths chosen for operation at different depths of focus. The total aperture of the transducer is divided into a plurality of contiguous focal depths. In the near field only the inner element or elements are activated, and rings of increasing radius are added as the depth of focus is increased. The widths of the rings are chosen to keep phase errors across each ring within acceptable limits over the depth of field for which they are energized. The transition depths at which the aperture is changed are chosen to allow rings of manufacturable widths to be employed while maintaining aperture transitions which prevent banding in the ultrasonic image.

Abstract: A system for testing the fabrication of objects utilizes echo-sounding techniques. A transmit transducer and a receive transducer which provide a conversion between electric and sonic energies are acoustically coupled to the object under test. A single cable connects the transducers to a single processor which generates, receives and analyzes the signals utilized in the test process. A coupling circuit connects one end of the single cable to the two transducers and isolates a transmitted signal from a received signal so as to permit their communication by the single cable. Within the coupling circuit, a transmitted signal is communicated by a set of serially connected diodes wherein the forward voltage drop is much less than the voltage of the transmitted signal, but greater than the voltage of an incoming signal such as a reverberation of the transmitted signal or a received echo signal.

Abstract: An ultrasound device for sector scanning which includes an ultrasound transmitting/receiving system. The system is housed in a compact cylindrical applicator housing which contains ultrasound transducer heads and associated ultrasound transducer elements at both ends of the applicator housing. Each of the two ultrasound transducer heads is rotatable within the applicator housing for performing sector scanning. A single drive mechanism rotates or swivels reciprocally both transducer heads so that undesirable inertial forces are cancelled or compensated. A guiding element pivotally supports the applicator housing so that the housing can be rotated and one or the other of the two ultrasound transducer heads be used. The guiding element also provides the enclosure for the electronics associated with the ultrasound applicator.

Abstract: An ultrasonic sensor for determining objects in air or other gaseous media is disclosed. The sensor comprises a first ultrasonic transducer having a piezoelectric transmitter. A reflector is provided having a concave surface facing the first ultrasonic transducer which forms a segment of an ellipsoid. The reflector has two focal points, the first of which is closer to the reflector and the second of which is near the object to be detected. Between the first ultrasonic transducer and the reflector, a second ultrasonic transducer is provided which is arranged at the first focal point of the reflector. Preferably, the surface of the second ultrasonic transducer facing the reflector forms a spherical segment. By this arrangement, an increase of the receiving aperture is achieved, and objects can be determined which have a normal to the reflection surface inclined with respect to the axis of the sound lobe by an object position angle which is substantially larger than .+-.3.degree..

Abstract: A method and an apparatus of ultrasonic flaw detection suitable for detecting internal cavern defects of a material, the method involving the mounting on a rotary body of a plural number of skew probes in equidistant positions in the circumferential direction of the rotary body to provide a corresponding number of channels for transmitting and receiving ultrasonic beams in a direction intersecting the axis of rotation of the rotary body at different depths in an inspection zone of a material positioned opposingly to the probes. The rotary body is turned to revolve the probes through 360.degree. about the axis of rotation while transmitting and receiving the ultrasonic pulses. Selected flaw patterns are produced from the peak values of the echoes received at the detection gates of the respective channels in relation with the direction of incidence of the ultrasonic beams.

Abstract: A first array (A) of ultrasonic transducers transmits ultrasonic shear waves circumferentially around an examined cylindrical object (110). A second array (B) transmits ultrasonic shear waves axially along the examined object. Triggering pulses from a triggering amplifier (22) are switched by a multiplexer (24) to each individual transducer of the first and second arrays. As one of the transducers assumes the role of a transmitting transducer and transmits an ultrasonic wave, the other transducers of the first and second arrays assume a receiving mode to receive reflected ultrasonic components. A wave travel timer (26) measures the duration for an ultrasonic wave to be transmitted from the transmitting transducer to a defect and for a reflected component to propagate from the defect to the receiving transducer.

Abstract: An ultrasonic method and apparatus are described for determining the depth of cracks 12 in a pipe or conduit 14. The apparatus 10 includes a transmitting transducer 30 and a receiving transducer 40 that are placed on the outside surface of the pipe to one side of the pipe. The transmit transducer 30 is energized to direct a shear wave beam 34 of ultrasonic energy at the crack to generate a complex reflected wave front from the crack 12 which contains information as to the size of the crack in relation to the wall thickness. The recovery transducer 40 is moved relative to the transmit transducer until a peak or maximum amplitude reading is found. When the maximum amplitude is found, the distance between the transducers is measured. The measured distance is then correlated with information obtained from specimens 80 of the same material and wall thickness as the on-site pipe to determine the depth of the crack 12.

Abstract: Ultrasonic diagnosis apparatus including a plurality of transducer elements in a probe actuated by electric pulses for emitting ultrasonic pulses, for receiving echo ultrasonic pulses, and for issuing electric pulses corresponding to the echo pulses; a pulse generator; apparatus for processing the electric pulse information issued by the probe; a photo transmission line interconnecting the pulse generator and the probe and interconnecting the probe and the processing apparatus; and devices for converting electric pulses to photo pulses for conveyance on the photo transmission line and devices for reconverting the photo pulses to electric pulses after conveyance on the photo transmission lines are utilized with M number of multiplexers. Each multiplexer has L number of taps to drive N number of transducer elements where N=M.times.L.

Abstract: An ultrasonic transmitter (10) and at least two ultrasonic receivers (12, 16) are mounted on a carrier (18) which traverses the surface (22) of a solid material (24). The sound beam (30) from the transmitter (10) passes beneath the surface (22) and enters a zone of interest disposed about a point (36) located a fixed distance (40) beneath the surface (22). Reflected sound beams (42, 46) emanating from flaws (54, 58, 60) located within the zone of interest are detected by the receivers (12, 16). The orientation and positioning of the transmitter (10) and the receivers (12, 16) for maximizing the detection and differentiation of the detected flaws (54, 58, 60) are also disclosed.

Abstract: A method and apparatus for ultrasound tomography for use in clinical diagnostics, the apparatus comprising paired couples of transmission transducers (3) and reflection transducers (5,6), the paired couples of transducer means being independently operable within a container (1) of ultrasound transmission medium to provide data capable of processing by computational methods for mathematical reconstruction of the distribution of specific values of acoustic data to permit separate comparative and synergistic examinations of the data thus obtained to classify the internal structure of a body.

Abstract: An ultrasound visualization system, and certain aspects of the electronics that are incorporated therein. A scan conversion system which includes means for converting the ultrasound scan signal into a stream of single bit digital data in which each bit is indicative of the relative amplitude of the ultrasound scan signal as compared to the amplitude indicated by previously converted digital data. The single bit digital data is inputted and stored alternately into two full screen buffers. As the data is read into one of the two full screen buffers, the stored data in the other buffer is being simultaneously converted into an analog television video signal. The digital to analog conversion is accomplished by varying an analog television video signal in response to the relative amplitude indicated by each bit in comparison with the amplitude indicated by previously converted digital data.

Abstract: A method for non-destructive, qualitative testing of properties of materials, whereby ultra-sonic waves are transmitted in the direction of the material. Ultra-sonic waves reflected by the material are received. The orientation of the material relative to the direction in which the ultra-sonic waves are transmitted is changed in a predetermined way, such that the transmitted ultra-sonic waves arrive at the material under varying angles of incidence and from different directions.

Abstract: An acoustic microscope comprising a transducer for transmitting acoustic signals towards the surface to be studied, and means for receiving at least one reflected signal from the surface; in many embodiments of the invention, signals are received from two separate points. The signals received are passed to a synchronous phase detection system for analysis. The signals may be received at the same phase detector input and separated according to their expected time of receipt relative to their time of transmission, or they may be received at separated points on the transducer related to their separated points of transmission. The separated return signals are compared on the basis of phase (and in certain embodiments, magnitude) differential either to each other or to an internally generated reference signal to analyze the surface characteristics of the material.

Abstract: An acoustic polarimeter is provided for measuring the acoustic birefringence of a plate with parallel faces.The plate to be measured is fixed to one face of an acoustically isotropic body and to the other face are fixed transducers having their linear transfer axis at 90.degree. from each other transmitting waves at pulsation .omega. modulated respectively by cos .OMEGA.t and sin .OMEGA.t. After reflection from the rear face of the sample, the signals X.sub.1 and Y.sub.1 received by the transducers are processed in processing circuits. The signals x.sub.1 and y.sub.1 are multiplied by a signal cos (.omega.t+.phi.) supplied by a phase-shifter controlled by a signal S.sub.1. After filtering, signals X and Y are obtained which are used for generating two signals A and B. A microprocessor receiving the amplitudes of these signals A and B controls the phase-shifter and supplies the birefringence angle .phi.. The direction of the first axis is obtained by synchronous detection of signal A.sub.1 by sin 2 .OMEGA.t.

Abstract: A phased array ultrasonic testing apparatus includes: an array probe for ultrasonic transmission and reception; a transmitter for sequentially exciting transducers of the probe in a predetermined order; a circuit for preparing a composite signal from reception output from the probe; and a circuit for preparing an image signal indicating an internal flaw of a tested body in synchronism with the composite signal in accordance with a transmission beam index point and a steered angle of an ultrasonic main beam.

Abstract: A transducer assembly is provided which performs simultaneous imaging and flow measurement. Separate imaging and Doppler transducers are mounted on one face of the assembly. Each transducer type is backed by backing material which provides damping in accordance with the performance criteria of the different transducer types. The transducer types may be mechanically focused in the same direction so that flow measurements are made in the center of the area being imaged.