Abstract: A process for selective graphic representation and/or evaluation of the Doppler spectrum of objects limitedly resistant to sonic intensity, for example biological organs and tissues, by an ultrasonic process wherein a material is introduced in the examination area to be acoustically irradiated, nonlinear oscillations are produced in the examination area by irradiated ultrasonic waves and the signal is evaluated by an ultrasonic converter. Also, a circuit for carrying out the above process is disclosed.

Abstract: Apparatus for imaging an object underwater. A detector array of operationally independent transducers is deployed in a medium such as water. Each transducer generates an electrical signal across independent first and second electrodes corresponding to impinging acoustic energy. Each of the positions in the detector array is identified in sequence along with the identification of a corresponding pixel position or display position in a display structure. A first multiplexer connects to all the first electrodes and a second multiplexer connects to all the second electrodes to enable the identification circuit to select corresponding electrodes for each detector position. A single amplifier circuit couples the signals from the multiplexer to a circuit for controlling the illumination of a selected display position.

Abstract: An ultrasonic imaging system for displaying color flow images includes a receiver which demodulates ultrasonic echo signals received by a transducer array and dynamically focuses the baseband echo signals. A color flow processor includes a time domain adaptive wall filter which automatically adjusts to changes in frequency and bandwidth of the wall signal components in the focused baseband echo signals. The mean frequency of the resulting filtered baseband echo signals is used to indicate velocity of flowing reflectors and to control color in the displayed image.

Abstract: An annular array scanner utilizes a synthetic focusing approach to improve imaging results. Image sharpening methods include corrections for the speed of sound of the image, phased array misregistration and separate view misalignment as well as inverse filtering for the scanning system point spread function.

Abstract: An array of acoustic sensors is positioned near the object to be imaged so that an array of detection beams impinge upon the surface of the object. The ambient noise in the ocean which is generated by both natural and manmade phenomena is reflected off of the target object and collected by the acoustic sensors. Each beam corresponds to a single pixel of an image of the object. The amplitude and frequency differences between the signals derived from each beam permit contrast to be developed between the pixels so that an image is formed. A first embodiment utilizes a parabolic or spherical reflector to focus the noise reflected from the object onto one or more sensors. A two dimensional array of sensors is required to produce an image. A second embodiment uses a phased array of acoustic sensors to form an image, with the phased array of sensors being used to generate a large number of scanned beams, each beam corresponding to one pixel of the image.

Abstract: A synthetic Mill's Cross scanner array is provided for a sonographic system. The array includes orthogonal lines for which projector and hydrophone are respectively provided. During a scan of a target volume, the projector and the hydrophone elements are moved from first paired positions to second paired positions, etc. to n paired positions. Data from the scan is processed to provide three-dimensional data for displaying the target volume.

Abstract: An apparatus and method for clutter elimination from signals which digitizes a signal to generate n samples of the signals. M basis functions (such as various levels of filters) are fit to the n samples. An i+1 basis function of the m basis functions is iteratively subtracted from each of the n samples, and the difference is stored in an i difference signal until the i+1 difference signal is less than a threshold. In various embodiments, the threshold may be an absolute noise floor (R.sub.O.sup.min) preset by a manufacturer or a user. In other embodiments, the threshold may be based upon an absolute or relative predictor error of the signal once the basis function (filter) has been removed. The i difference signal may be used for performing a frequency estimate of the signal.

Abstract: An acoustic search device comprises an ultrasonic transducer with a plurality of elements for transmitting acoustic signals toward a viewed search area and for receiving echo signals therefrom, a display, an electronic unit and an optical viewing device. The electronic unit controls the transducer and the display which shows a display image of the viewed search area based on the echo signals reflected from the viewed search area. The display image is seen by means of the optical viewing device. The optical viewing device, the display, and the ultrasonic transducer are arranged to form a part of the protective cap of a diver and are situated in a protective cap, substantially in succession in the direction of sight of the diver.

Abstract: An apparatus for the examination of an object by ultrasonic echography, includes an array of n ultrasonic transducers which is associated with a stage for the emission of signals for scanning the object and with a stage for receiving and processing echographic signals retumed to the transducers, by the obstacles encountered in the object scanned. The emission stage is configured for the focusing of m simultaneously emitted ultrasonic beams, by virute of n emission modules, each of which, for example, the i.sup.th emission module, itself contains m signal generators (201a.sub.1, . . . , 201m.sub.1) which are connected in parallel (or a single signal generator followed by m parallel-connected delay circuits), a stage (202i) for combining the m signals thus generated, and an amplifier (203i) for applying the amplified combined signal to the transducer (10i) corresponding to the relevant emission module.

Abstract: A method to quantify the distortions caused by near filed variations in the propagation medium of pulse echo imaging systems. By estimating the phase lags induced by the aberrator at each point on the aperture, appropriate electronic delays might be applied to the signals associated with each array element in order to restore the system to focus. The method is capable of estimating the set of aberrating delays in an imaging phased array by using appropriate data from a single two or three dimensional pulse echo scan.

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: A preferred embodiment of a large diameter solid ultrasonic imaging transducer is illustrated in FIG. 5 with alternate embodiments illustrated in FIGS. 6-9. The large diameter solid ultrasonic imaging lens 100 has a diameter preferably greater than six inches with a focal length-to-diameter ratio of between 1 and 2. The lens 100 has concave surfaces 108 and 110, and is composed of a homogenous material that has an ultrasonic impedance of less than twice that of water and has a density less than the water. Preferably, the velocity of the ultrasonic sound through homogenous plastic material is less than twice that of water. One or both of the concave surfaces 108 and 110 have surfaces that are without a constant radius and curvature, but however are composed of separate radius of curvatures for each small increment of lens surface to properly focus the ultrasound at a desired focal length "L".An alternate embodiment is illustrated in FIG.

Abstract: Signal processing apparatus and methods for elimination of undesirable clutter signals from desirable signals. This is performed without the use of filters by subtracting orthonormal basis functions from signal samples until the appropriate degree of clutter removal is achieved. Estimates of frequency information such as Doppler shifts due to fluid flow may thus be achieved with superior discrimination of true flow signals from sources of clutter or artifact, greater sensitivity to low flow rates, minimal computational effort and with fewer samples than the prior art.

Abstract: Coherent light is projected through a scattering medium. The light emerging from the medium is a superposition of a multitude of scattered wavelets, each of which represents a specific scattering path. These wavelets are projected onto a diffuse reflecting surface (the viewing plane of a two-dimensional photodetector array) where they interfere with each other, giving rise to a speckle pattern. By introducing a focused ultrasound pulse into the medium, the position of the scatterers are changed at a known location (probe region) in the medium, and this causes a change in the speckle pattern. By comparing speckle images before and after the scatterers are moved, the light absorption properties of the probe region can be measured even though multiple scattering interferes with direct imaging of the region.

Abstract: For reducing speckle in echo signals derived from reflections of pulsed coherent waves, the echo signals are subjected to amplitude and phase/frequency demodulation and the resultant amplitude and phase/frequency data are multiplied to generate an image signal. Selective control of the multiplication process may be provided in accordance with signal amplitude and/or signal-to-noise ratio.

Abstract: A foreground image is overlaid over a background image on a visual display. Specifically, an ultrasound signal is transmitted toward a target to be displayed in two dimensions. Echoes of the ultrasound signal are received from the target. Two-dimesional target data acquired from the received echoes are stored. The two-dimensional target data are presented on the visual display as a background image. Part of the target data are overlaid over the background image as a foreground image on the visual display. The size of the foreground image vis-a-vis the background image is changed by the user to permit better observation of an area of interest. Preferably, the size of the foreground image is changed without changing the area occupied by the foreground image on the visual display, which permits the invention to simulate the action of a magnifying glass. The user moves a cursor on the visual display to the center of an area of interest.

Abstract: A PASS ultrasonic system performs a scan in which phase errors due to aberrations in the sound media are corrected prior to the acquisition of each beam. Phase errors are measured by cross correlating each of a set of reference beams with the desired beam to produce beam forming errors as a function of beam angle. This function is Fourier transformed to produce phase corrections that are employed by the ultrasonic system to offset the phase errors.

Abstract: A system for radiation imaging of an object in response to echo signals from a target area of the object, such as a region of the anatomy of a body. Data is obtained by time domain measurements at monostatic transducers which can be disposed in different locations. The data is processed by two-dimensional Fourier transformations reconstructed using a mapping function and which compensates for variation in the radiation pattern at the various detector locations by using a phase correction function which avoids the need for Fresnel or plane wave approximations.

Abstract: The invention relates to a simple, cheap sonar system with high image rate, for the detection of objects and the imaging of sea bottoms. It consists in transmitting n uncorrelated successive codes in a sector of angular width exactly equal to n times the angular width of the reception sector .theta..sub.R, the reception antenna continuing to turn during this time whilst the first signal transmitted has not yet reached the maximum range dmax, and in receiving, in the sector of angular width .theta..sub.R, the echoes of these n codes, coming from n propagation regions which are adjacent in relation to the reception axis, and lying between 0 and dmax in space, each of them having a depth equal to dmax/n.

Abstract: Optical radiation is propagated through an attenuating medium to a target om which it is reflected and picked up by an echo receiver system to provide ranging and imaging data during one mode of operation. The optical radiation is transformed into acoustical pulse energy alternatively radiated to and reflected from the target in another mode of operation. The operational mode is selected so as to optimize the data extracted from the echo receiver system under different conditions affecting receiver reception.

Abstract: A method of locating objects in sonar images so that matching algorithms can be used to determine if the same objects appear in two images. Information from the matching algorithms can then be used to upgrade the position of the vehicle and objects recorded in the vehicle's navigation system. Images are improved by normalizing brightness and contrast and then convolving the image with at least one filter. The image is normalized by dividing the image into vertical strips, creating a histogram to represent the grayness values for columns of pixels in each strip and applying an algorithm to each strip to change its grayness value.

Abstract: A phased array sector scanning (PASS) ultrasonic imaging system produces a steered transmit beam with an array of transducer elements that are driven with separate carrier frequencies. A receiver forms the echo signal into a receive beam steered in the same direction as the transmit beam and is dynamically focused. A transmit beam processor Fourier transforms this receive beam to produce a signals corresponding to the separate carrier frequencies which can be delayed to retrospectively dynamically focus the transmit beam or alter the direction in which it is steered.

Abstract: The train of echoes received in an ultrasound imaging system having an array of ultrasound transducers is shaped and/or focused by first and second programmable beam focusing modules (16-24) in a dynamic receive focus mode. The elemental ultrasound echo signals from a plurality of channels connected to the elements of the transducer array are selectively attenuated and/or phased shifted according to the programs prescribed for the focus zones and combined by each module. The combined echo signals are further processed in conventional fashion (34-38). The modules operates alternately. One module is being programmed, while the other module is combining the elemental echo signals for processing. Each beam focusing module comprises a delay line (56-60) having a plurality of input taps and a cross point switch (52) selectively connecting the channels to the input taps. The module is programmed by selectively closing the individual cross points of the cross point switch. Beam shaping i.e.

Abstract: This invention relates to low transient switching apparatus, and more particularly to switching arrays of low transient switching circuits which are adapted for use to substantially continuously focus transducer channel outputs in an ultrasonic scanning system. A separate switching array is provided for each channel. Each array has a switching circuit with an output for each focusing delay line tap to which a signal on the channel may be applied. Each switching circuit provides a substantially constant D.C. current output regardless of the state of the circuit. Array outputs for each delay line tap are summed, and the summed outputs are applied as the input to the tap. The DC current inputs to all taps are maintained substantially equal, preferably at zero DC current.

Abstract: The train of echoes received in an ultrasound imaging system having an array of ultrasound transducers is shaped and/or focused by first and second programmable beam focusing modules in a dynamic receive focus mode. The elemental ultrasound echo signals from a plurality of channels connected to the elements of the transducer array are selectively attenuated and/or phased shifted according to the programs prescribed for the focus zones and combined by each module. The combined echo signals are further processed in conventional fashion. The modules operates alternately. One module is being programmed, while the other module is combining the elemental echo signals for processing. Each beam focusing module comprises a delay line having a plurality of input taps and a cross point switch selectively connecting the channels to the input taps. The module is programmed by selectively closing the individual cross points of the cross point switch. Beam shaping i.e.

Abstract: The train of echoes received in an ultrasound imaging system having an array of ultrasound transducers is shaped and/or focused by first and second programmable beam focusing modules (16-24) in a dynamic receive focus mode. The elemental ultrasound echo signals from a plurality of channels connected to the elements of the transducer array are selectively attenuated and/or phased shifted according to the programs prescribed for the focus zones and combined by each module. The combined echo signals are further processed in conventional fashion (34-38). The modules operates alternately. One module is being programmed, while the other module is combining the elemental echo signals for processing. Each beam focusing module comprises a delay line (56-60) having a plurality of input taps and a cross point switch (52) selectively connecting the channels to the input taps. The module is programmed by selectively closing the individual cross points of the cross point switch. Beam shaping i.e.

Abstract: A conical ultrasonic wave deflection system has an ultrasonic transducer for ultrasonic microscopy using surface waves and/or Lamb waves in an object. A conical wave front is directed onto the object via a deflection element. An inactive axial circular disk is provided between the ultrasonic transducer and the object to minimize unnecessary interference from undeflected waves. A frustoconical lens with a blocked top face, or a conical metal reflector with a ring transducer on the transducer side can be provided as the deflection element. The arrangement is highly compatible with ultrasonic microscopes. Matching to a critical angle .theta. of the object is achieved by selection of the appropriate ultrasonic frequency.

Abstract: The present invention is generally directed to an apparatus and method of echo identification wherein the sources of echoes generated from interface boundaries in a medium may be more effectively identified in the processing of obtained waveform data to generate higher resolution in the obtained data. The method of the present invention is particularly useful for performing ultrasound reflectometry and medical sonography by obtaining data representative of a medium being studied and suppressing signals from overlapping echo waveforms generated from obstacles adjacent an object under test. More particularly, the method of the invention enables the sources of such echo waveforms to be more effectively identified to yield an indication of the contribution of overlapping echoes to generate higher resolution data signals. The processing includes generating a power spectral estimate of the data which is utilized to obtain a phase estimate thereof.

Abstract: An acoustic imaging method for nondestructive evaluation of materials comprises the steps of measuring the temperature dependence of the acoustic wave transmittance of the material in advance, cooling the material to a temperature at which its acoustic wave transmittance is high, and carrying out acoustic imaging.

Abstract: An acoustic microscope in which acoustic energy is focused onto a membrane which includes an aperture which is a fraction of the size of the focal spot of the acoustic beam at the membrane to form fringing fields on the other side of the membrane. Acoustic energy reflected from the membrane is detected. An object to be examined is placed in cooperative relationship with the fringing fields.

Abstract: A beam former method and an apparatus therefor in an ultrasonic imaging system, in which switching of delay elements is performed by means of delay switches in a section in which no ultrasonic wave transmission/reception is performed and switching noise generated in this section is stored as a noise signal into a memory. The stored noise signal is subtracted from a reception signal which is obtained through ultrasonic wave transmission/reception and which contains switching noise superimposed thereon to thereby obtain a reception signal from which the noise has been eliminated.

Abstract: A probe for an ultrasonic microscope is disclosed. The probe has an element for radiating and receiving an ultrasonic wave and an acoustic lens for causing an ultrasonic wave, which has been generated by the element, to converge at a point into an ultrasonic beam, whereby the ultrasonic beam is radiated against a sample and a reflected wave of the thus-radiated ultrasonic beam is received by the element to convert the reflected wave into an electrical signal proportional to the reflected wave. A mask is provided on a side of the sample relative to the acoustic lens. The mask is composed of an ultrasonic wave transmitting portion and an ultrasonic wave blocking portion. The transmitting portion permits the transmission of first beam components, which take part in producing an elastic surface wave in one direction in a surface layer of the sample, and second beam components which take no part in the production of any elastic surface wave.

Abstract: Disclosed is an ultrasonic probe for use in medical diagnostic systems for examination within a human body. The ultrasonic probe comprises an array of transducer elements for transmission of ultrasonic wave into an examined body and for reception of echo waves returning from the examined body. Further included in the ultrasonic probe is an ultrasonic propagation medium which is provided between the transducer element array and the examined body. The ultrasonic propagation medium is made of a synthetic rubber having an acoustic impedance close to that of the examined body and having a low acoustic attenuation coefficient. Preferably, the synthetic rubber is one of butadiene rubber, butadiene-styrene rubber, ethylene-propylene rubber, and acrylic rubber.

Abstract: An acoustic receiving array synthesized using a single stationary receiving lement and a rotating target. Echoes from a highly repeatable transmit pulse are digitized and recorded as the target is rotated. Controlled geometry and essentially stationary channel characteristics eliminate the need for adaptive beamforming techniques. Subsequent to acquisition of the desired data set conventional time delay beam-forming and steering techniques for multi-dimensional arrays are used to focus the array at desired locations. Energy level in a time gate is computed and recorded for each image location. Finally a raster image is generated using the thresholded energy levels.

Abstract: An ultrasound probe for a medical imaging system, comprising an ultrasound absorber and a piezoelectric vibrator mounted on the ultrasound absorber, cut in the direction from the surface of the piezoelectric vibrator to the ultrasound absorber into an array by a plurality of cutting grooves. The cutting depth d of each cutting groove in the ultrasound absorber is determined as an integer multiple of a quarter of a wave length .lambda. corresponding to a center frequency f.sub.0 of ultrasound waves radiated from the piezoelectric vibrator. Consequently, symmetrical electro-acoustic conversion characteristics of the ultrasound probe can be obtained in the frequency domain.

Abstract: An ultrasonic microscope includes a sample rod for supporting a sample and an acoustic lens positioned to face the sample. The lens is moved in two directions in a plane perpendicular to each other to scan the sample. During the scanning operation, the lens is also moved in a vertical direction so that the distance between the sample and acoustic lens is changed, by a piezoelectric actuator for supporting the lens.

Abstract: An ultrasound apparatus has a transducer array which includes a number of individual transducer, each transducer having a channel exclusively associated therewith. In an input stage for the ultrasound apparatus, an analog stage is provided in each channel to which the echo signals for a transducer associated with that channel are supplied. This analog stage concludes with an analog-to-digital converter in each channel. The output of the analog-to-digital converter is connected to a further processing circuit in each channel for the acquisition of Doppler signals of moving target echoes. A combined ultrasound imaging device and Doppler device is thus achieved, which allows the acquisition of Doppler signals with the digital input technology of the ultrasound imaging processing circuit. This permits expansion of digital operating RF input components of imaging devices to include Doppler signal processing.

Abstract: An ultrasound system for investigating a subject comprises a probe, a signal processing module, and an interconnecting cable. The probe includes an annular phased array transducer defining multiple signal processing channels. The signal processing module includes a controller, a transmitter, a receiver, delay circuitry, and a video section. Within the delay circuitry, each signal processing channel includes an inphase branch and a quadrature branch. Each branch includes an analog-to digital converter (ADC) and a delay first-in-first-out (FIFO) memory. Dynamically variable delays are implemented by varying the sampling and FIFO input rates relative to constant FIFO output rates. The variable clock rates are derived by switching between phase-staggered replicas of a master clock MCLK, which has a rate at the nominal center frequency of the ultrasound signal prior to sampling.

Abstract: An ultrasonic imaging apparatus includes an ultrasonic transducer for outputting an ultrasonic beam and converting the echo of the ultrasonic beam into an echo signal, a transmitter section for supplying a drive signal to the ultrasonic transducer, a receiver section for receiving the echo signal output from the ultrasonic transducer and converting the echo signal into an image signal, and a coaxial cable for coupling the ultrasonic transducer to the transmitter and receiver sections. The ultrasonic transducer is constituted by a two-layer ultrasonic transducer having an impedance smaller than an impedance of the coaxial cable.

Abstract: An ultrasonic diagnostic apparatus for obtaining ultrasonic images of a body to be inspected by selectively using a plurality of ultrasonic vibrating elements having different frequency characteristics, including a chirp signal generating circuit for generating a chirp signal selected from a plurality of chirp signals each corresponding to respective ultrasonic vibrating elements, a plurality of pulse compression circuits each having a reference wave signal corresponding to respective chirp signals and compressing the echo signal by deriving a correlation of the echo signal with the selected reference signal, and a switching circuit for selecting one of the pulse compression circuits in accordance with the selected chirp signal corresponding to the ultrasonic vibrating element to be used.

Abstract: An electronic signal processing device which forms a compound image for any pulse-echo ultrasound imaging system using a two-dimensional array transducer. The processing device obtains the detected sum of a series of cross-shaped apertures within the transducer in order to form a spatial compound image with the output of each cross-shaped aperture consisting of the product of the output signals from the orthogonal arms of the cross.

Abstract: In a pulse compression apparatus for use in an ultrasonic diagnostic apparatus in which an ultrasonic chirp pulse whose frequency is increased or decreased in time is emitted toward a body under inspection, an ultrasonic wave reflected by the body is received to generate an echo signal, a correlation between the echo signal and a reference wave is derived to compress the echo signal, and an ultrasonic image is formed in accordance with the compressed echo signal, the reference wave is formed by processing an echo signal reflected from a reference body having a known acoustic property or an ultrasonic wave permeable window of a cap which surrounds an ultrasonic vibrating element, and the thus formed reference wave is stored in a memory.

Abstract: This invention relates to a method and apparatus for automatically controlling scan line direction in a linear array ultrasonic Doppler scanning system. More particularly, this system determines an ideal scan line angle and point of origin for a given sample volume having fluid flow in a given direction. The system then determines left and right limiting angles for the given sample volume taking into account the geometry of the viewing area relative to the sample volume and the maximum steering angle of the transducers of the transducer array being utilized. Where, because of pulse repetition rate considerations, a maximum depth from the sampling aperture of the linear array to the sample volume exists, this maximum depth is also taken into account in determining the limiting angles.

Abstract: An ultrasonic imaging apparatus comprises an ultrasonic probe, a transmitter/receiver circuit for driving the ultrasonic probe to emit an ultrasonic beam and processing an echo signal output from the ultrasonic probe and junction unit coupled between the ultrasonic probe and the transmitter/receiver circuit and including an impedance transforming circuit having a high input impedance and a low output impedance for taking in an echo signal output from the ultrasonic probe at high impedance and outputting the taken-in echo signal at low impedance.

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: An echo ultrasound imaging system comprising at least one array of elementary transducers, and further comprising an emission stage and a stage for the reception and for the processing of echoes reflected back towards the said array, said reception and processing stage having means for the simultaneous focusing of M ultrasonic beams originating from M different directions; the emission stage has means for the focusing of M ultrasonic beams emitted sequentially in the said M different directions, and during a total duration defined by the sum of the M maximum delays of the M delay laws forming the said M focused beams emitted.

Abstract: A volume is scanned with a raster scan about a center of rotation using a transmitter/receiver at a selected range while gating a range window on the receiver with a selected range differential. The received signals are then demodulated to obtain signals representative of a property within the volume being scanned such as the density of a tumor. The range is varied until the entire volume has been scanned at all ranges to be displayed. An imaging display is synchronously scanned together with the raster scan to display variations of the property on the display. A second transmitter/receiver with associated equipment may be offset from the first and variations displayed from each of the transmitter/receivers on its separate display. The displays may then be combined stereoscopically to provide a three-dimensional image representative of variations of the property.

Abstract: An acoustic sensing system to measure a geometry parameter such as, for example, position, orientation and/or shape of an object. The system includes a transmitter for transmitting acoustic wave energy at a single frequency, which acoustic wave energy, in an operating system, interacts with the object in a sensing region to provide reflected or scattered wave energy. A sensor mechanism consisting of many acoustic transducers is positioned to receive the reflected or scattered wave energy, each transducer being operable to convert the received acoustic wave energy to an electrical signal. A processor is connected to receive the electrical signals from the plurality of acoustic transducers; the processor is operable to obtain amplitude and phase information with respect to the electrical signal from each of the transducers, the amplitude and phase information from each of the plurality of transducers being combined and analyzed to derive a geometric parameter of the object.

Abstract: A contact ultrasonic transducer head assembly. A stationary housing is adapted to be fitted to a remotely operated manipulator. A movable assembly slidably received by the stationary housing has a plurality of independently suspended ultrasonic transducers mounted thereon. A position encoder mounted in the movable assembly monitors movement within the stationary housing. A limit switch is used to electrically disable the remotely operated manipulator when the movable assembly slides a predetermined distance into the stationary housing to prevent damage to the transducers or the surface being inspected.

Abstract: Imaging apparatus including an array of transmitters for simultaneously transmitting more than two coded signal beams in different directions to cover different regions of a field of view, said beams being modified by objects within said field of view, signal means for providing individual coded signals to respective transmitters, at least one receiver for simultaneously receiving plural coded modified signals derived from the coded signal beams, and a processor for separating the plural coded modified signals of different codes and processing them into an image signal.