Abstract: During testing of a panel-like workpiece by means of ultrasonic penetration and at least one inspection channel comprising an ultrasonic transmitter and an ultrasonic receiver on opposite-lying sides of the workpiece, diverse test signals and test information are accumulated at the ultrasonic receiver. Each ultrasonic receiver is connected to an evaluation system, in which the test signals and the test information are combined, evaluated and reduced to a single piece of result-information which describes the tested workpiece. If at least two inspection channels are provided, it can also be provided that a reduction to a single piece of result-information is performed in each case for each ultrasonic receiver.

Abstract: A method and apparatus for determining stress levels of membrane masks that may be used in membrane-based lithographic techniques is presented. A piezoelectric plate (30) is used to induce vibrations into the membrane mask (35), where the frequency and amplitude of the vibrations induced in the membrane layer (50) are optically sensed. By comparing the stimulus applied to the piezoelectric plate (30) with the response sensed optically in a gain phase analyzer (80), a frequency graph (110) associated with the membrane layer (50) is constructed such that resonant frequencies are easily determined. These resonant frequencies can then be used to calculate the stress associated with the membrane layer (50).

Abstract: An ultrasonic detection method and apparatus are suited for real-time collection of three-dimensional ultrasonic data.

Abstract: Ultrasonic techniques are applied to the measurement of wooden members to detect splitting during sawing operations and thereby allow modification of a sawing technique or change in saw cut placement.

Abstract: A contaminant sensor is provided which has an ultrasonic guided wave transducer that is bonded to a wall in which the ultrasonic energy is transmitted. A detector reflector is provided at a selected distance from the transducer, which will reflect signals that are affected or changed by contaminants collecting on an exposed surface of the wall. A self test reflector is positioned closely adjacent to the transducer and provides a reflected signal that is substantially unaffected by contaminants on the exposed surface of the wall, but which reflects signals only when the transducer assembly is functioning properly, and is properly bonded to the wall. The signal that is reflected by the self test reflector changes when the bond loosens. The receiver is activated right after transmission ceases to determine if the transmitter is operating.

Abstract: A method of and apparatus for discriminating among ultrasonic echoes reflected from various objects in a tank containing liquid is disclosed. Ultrasonic signals are generated from an ultrasonic transducer into liquid contained in a tank. Ultrasonic echoes are received by the transducer from various objects in the tank including a surface of the liquid in response to the generated ultrasonic signal and are converted into electrical echo signals representative thereof. Data samples of the electrical echo signals are generated and processed by a signal processor using wavelet function processing to generate wavelet coefficients thereof in a wavelet domain. The wavelet coefficients of the echo data samples are used to discriminate the ultrasonic echoes reflected from the various objects in or part of the tank. In one embodiment, echoes reflected from the liquid surface are discriminated from echoes reflected from other objects based on the wavelet coefficients of the echo data samples of each.

Abstract: Ultrasonic techniques are applied to the measurement of wooden members to detect splitting during sawing operations and thereby allow modification of a sawing technique or change in saw cut placement.

Abstract: In a cylindrical transducer constructed of a plurality of ultrasonic transducer arrays arranged in a circular form, the ultrasonic transducer arrays is divided into a plurality of groups, and tilt angles of transmitting and receiving beams are controlled to compensate for swing motions of the cylindrical transducer depending on which group the individual ultrasonic transducer arrays belong. Provided that the uncompensated tilt angle of the beam is a and the angle of inclination of the cylindrical transducer in a particular direction is b, the tilt angle of the beam formed by a transducer array in the inclining direction should be adjusted to &agr;−&bgr; and the tilt angle of the beam formed by a transducer array in the opposite direction should be adjusted to &agr;+&bgr;.

Abstract: A vehicle interior monitoring system to identify, locate and monitor occupants, including their parts, and other objects in the passenger compartment and objects outside of a motor vehicle, such as an automobile or truck, by illuminating the contents of the vehicle and objects outside of the vehicle with electromagnetic, and specifically infrared, radiation and using one or more lenses to focus images of the contents onto one or more arrays of charge coupled devices (CCD arrays). Outputs from the CCD arrays are analyzed by appropriate computational means employing trained pattern recognition technologies, to classify, identify or locate the contents or external objects. In general, the information obtained by the identification and monitoring system is used to affect the operation of some other system in the vehicle.

Abstract: The invention relates to an ultrasonic measuring instrument comprising a housing which contains a transducer for transmitting and receiving ultra-sound waves, and a rotatable mirror placed inside the housing for directing ultra-sound waves coming from the transducer through a tapering window comprised in the housing to an object of measuring outside the housing, and for directing ultra-sound waves which are reflected by the object of measuring and which enter the housing through the window to the transducer. Around, and rotating with the mirror a tube is provided, comprising a recess for the passage of ultra-sound waves.

Abstract: A flaw detection system using acoustic Doppler effect for detecting flaws in a medium wherein there is relative motion between the medium and system includes a transducer, spaced from the medium to be inspected, for introducing to and sensing from the medium an acoustic signal that propagates in the medium at a predetermined frequency; and a detector, responsive to the sensed propagating acoustic signal, for detecting in the sensed acoustic signal the Doppler shifted frequency representative of a flaw in the medium.

Abstract: An apparatus and method for the remote, noncontact evaluation of structures and containers at large distances (on the order of several meters) in air is described. The invention utilizes an air-coupled, parametric acoustic array to excite resonance vibrations of elastic, fluid-filled vessels and structural members. A nonlinear mixing process in the air medium transforms highly directional, narrow beamwidth higher acoustic frequencies into lower acoustic frequencies suitable for vibrational excitation of common structures. The parametric array also has an advantage for nondestructive evaluation applications in that it is capable of producing a broader bandwidth than typical linear devices, such as speakers and ultrasonic transducers. Typical carrier frequencies are in the 200 kHz range, and the sound field 3 m from the array has been demonstrated to have a bandwidth of greater than 25 kHz at a center frequency of 15 kHz.

Abstract: In order to determine the nature of fluid passing through a pipe, for example whether material being pumped through a pipe is sludge or liquid phase, high frequency ultrasonic pulses from a generator are caused to propagate around a peripheral wall of the pipe to produce ringing in the pipe, and the characteristics of the ringing are measured and compared in a controller with stored data to determine the nature of the fluid content of the pipe. A sludge pump may be controlled according to whether the data obtained shows that the material passing through the pipe is sludge or liquid tunnelling through the sludge.

Abstract: A plate (12) or pipe wall is inspected by coupling an ultrasonic transducer (14, 16) to its surface so as to generate a compression wave or lateral wave (26) along the surface and a shear wave or head wave (28) along the surface and a shear wave or head wave (28) at the shear-compression critical angle (.theta..sub.c) The same transducer (14, 16), or an additional transducer (15, 16) also coupled to the surface, detects a series of ultrasonic peaks corresponding to each generated ultrasonic pulse. Each such detected peak corresponds to ultrasonic energy traveling, partly as lateral waves (26, 32) on one surface or the other, and partly as head waves (28, 30) crossing a certain number of times between the surfaces. The transducers (14, 15) may be over 0.5 m apart, and substantially all the intervening parts of the plate (12) are inspected.

Abstract: Apparatus (10) for processing a return waveform generated by directing an ultrasonic pulse at an object (S) under test. A signal converter (12) converts the return waveform from an analog to a digital signal. The analog-to-digital conversion rate is approximately four times the operating frequency of the ultrasonic pulse. A signal processor includes a plurality of digital signal processors (14,16,18) each of which is separately controllable to process the converted digital signal. A communications network (20) directs the analog signal, converted digital signal, and an output signal from the signal processor to a visual display (28) and to various peripheral equipment (A1,A2) connected to the apparatus. A process controller (22) controls routing of these signals to and from the signal processor over the communication network. By processing a return waveform, peak amplitude values representing flaws or imperfections in the object can be determined and the processed waveform, including peak values, displayed.

Abstract: Ultrasonic apparatus determines the fluid depth, volume, and temperature in a storage tank. A system description for monitoring an underground storage tank containing gasoline is described. The system determines the water's and gasoline's depth, volume, and temperature. The apparatus consists of a remote console, ultrasonic probe, and interconnecting cable. The remote console contains a display to report tank information and a computer to operate the probe. The probe consists of an ultrasonic transducer above the bottom of the probe facing upwards to transmit and receive ultrasonic signals, vertically spaced reflectors and a temperature sensor to measure fluid temperature.

Abstract: A sensor plate is formed as an acoustic channel on which an acoustic transducer is mounted to send ultrasonic waves along a surface of a base wall of the acoustic channel which is exposed to contaminants to be detected. An insert plate encloses the channel to protect the surface opposite the surface exposed to contaminants from the environment. Thus, dirt, moisture, installation adhesives or other materials that might degrade the performance of the sensor are prevented from contacting the backside of the plate carrying the acoustic waves. Such acoustic channel sensors are useful in applications on aircraft surfaces, road surfaces, bridge surfaces and the like for detecting ice.

Abstract: An apparatus for aiming an ultrasonic beam to nondestructively test an object has an ultrasonic transducer for generating the ultrasonic beam having a beam axis and impinging the ultrasonic beam upon the object. The apparatus includes a laser aiming apparatus for directing at least one laser beam having a laser sight line substantially coaxial with the ultrasonic beam axis.The laser aiming apparatus, in one embodiment of the invention, includes a cross-hair apparatus for generating a laser beam cross-hair having a center along the laser sight line. Another embodiment of the present invention provides an ultrasonic mirror apparatus for bending the ultrasonic beam and which has a mirror made of a material that is substantially transparent to the laser beam.

Abstract: Acquired signals representing samples of propagating wavefields are processed using space-time linked variable methods to form images having better definition and resolution than may be obtained by conventional methods. Frequencies accessed include those anticipated as well as some apparently beyond those deemed feasible according to Nyquist criteria as well as those present in the wavefield source.The signals and physical features may be obtained in tomography (medical CT scans), echo location (radar or sonar) or seismic imaging for example. Signals are processed maintaining interrelation of the linked variables of time and space, rather than following the conventionally accepted current techniques which treat the time and space variables independently.Definition and resolution of images are obtained beyond those normally considered possible with earlier techniques by understanding and correctly interpreting the information content of a sampled wavefield.

Abstract: The number of transducers in the scanning of an ultrasonic field from an object is reduced by providing ultrasonic collectors at spaced apart locations in the medium and transmitting the ultrasonic waves which are collected to a transducer through waveguides or paths having different transit times. The waveguides can be individually of different lengths or can be of equal length and terminate at different distances along a common collecting waveguide.

Abstract: An inspection apparatus and associated method includes a sensor housing defining an internal cavity in which a sensor is at least partially disposed for inspecting the surface of a structural part and for detecting defects in the surface and the substructure of the part. The inspection apparatus includes a plurality of compliant fibers extending outwardly from a first end of the sensor housing and circumferentially about an opening defined by the first end of the sensor housing. The compliant fibers support the sensor housing above the surface of the part and maintain the sensor in a predetermined position relative to the surface of the part. The plurality of compliant fibers are adapted to flex laterally to accommodate obstructions on the surface of the part, such as raised fasteners, doublers or lap joints while maintaining the sensor in the predetermined position relative to the surface of the part.

Abstract: A method and apparatus for sizing a surface-connected planar crack through a gas- or liquid-filled gap. Ultrasonic energy having a frequency equal to the resonant frequency of the gap is emitted toward the crack edge. A first portion of the energy is back-scattered by the crack edge toward the emitter in a detection mode and a second portion is scattered by the crack edge toward a surface to which the crack is connected, which reflects the second portion toward a detector. The difference between the respective times-of-flight from emission to detection of the first and second portions is measured and used to determine the depth of penetration of the surface-connected crack. The paths traveled by the first and second portions of said emitted ultrasonic energy substantially intersect at the gap. A similar method also applies in sizing buried planar cracks across fluid-filled gaps.

Abstract: A method and apparatus for detecting pipe penetration by the bore head of horizontal boring machine utilizes acoustic and seismic sensors. A sensitive acoustic microphone is placed in the bottom of the nearest sewer manhole to the location of the bore head to detect acoustic signals transmitted through the ground by the bore head for producing a first output signal. A seismic pickup device is placed in the vicinity of the bore head to detect vibrations of the ground caused by the bore head, as it moves through the ground, to produce a second output signal. These first and second signals produced, respectively, by the microphone and the seismic pick-up device, then are supplied to a two-channel strip chart recorder, which provides an output indicia permitting simultaneous comparison of the two signals. Particular patterns of these detected signals are indicative of the penetration of a sewer pipe.

Abstract: A method for internal inspection of pieces having an interface with a propagation medium, is described. The steps include: illuminating a reference piece with an ultrasound beam from a first array of transducers excited by stored excitation signals; sensing reflected echo signals received by transducers, which may be the transducers of the first array, and storing the waveforms and time distribution thereof; simultaneously sensing refracted signals, received by transducers belonging to a second array placed opposite to the the first relative to the piece and storing the waveforms and time distribution of the signals received by the transducers of the second array; replacing the reference piece with a piece to be inspected having the same shape and occupying the same location, and applying, to each of the transducers, energization signals obtained by time reversal of the stored waveforms and time distribution; and sensing the signals received by the transducers of the second network.

Abstract: An ultrasonic wave is applied to an anisotropic sample material in an initial direction and the intensity of the ultrasonic wave is measured on an opposite surface of the sample material by two adjacent receiving points located in an array of receiving points. A ratio is determined between the measured intensities of two adjacent receiving points, the ratio being indicative of an angle of flux deviation from the initial direction caused by an unknown applied load. This determined ratio is then compared to a plurality of ratios of a similarly tested, similar anisotropic reference material under a plurality of respective, known load conditions, whereby the load applied to the particular anisotropic sample material is determined. A related method is disclosed for determining the fiber orientation from known loads and a determined flux shift.

Abstract: A measurement system for measuring the time for a signal to pass between two transducers TDR1,2 to allow fluid speed or flow to be determined in a gas meter for example. Each transducer can transmit or receive signals. The system is controlled by a microcontroller 31 and a signal with a phase change acts as a marker which is transmitted from transmitter 21 via matching stage 22,23 from one transducer and is received by the other. On receipt via the matching stage and amplifier 24 it is sampled by capacitor array 25 and detected in detector 29. Amplitude information from array 25 is made available to the microcontroller to compute time of signal travel and hence flow rates.

Abstract: A system and method for determining the condition of one or more parameters of a valve, e.g., particularly a check valve in a fluid carrying pipe, by monitoring fluid turbulence downstream of the valve. An ultrasonic transmitter-receiver transducer pair provides a signal modulated by the fluid turbulence, which signal is demodulated and processed to obtain a signature or other signal indicative of the valve condition. The processes signature signal may additionally be compared with a measure of flow rate determined just upstream from the valve. By operating the ultrasonic system at high frequency and using appropriate detecting circuitry, low frequency interference from mechanical shocks and vibrations is avoided, yielding a reliable detection of the flow turbulence caused by the valve.

Abstract: The disclosure is directed to a circuit for producing electrical discharges in response to trigger signals, and a form of the disclosure is directed to an apparatus, which includes such a circuit, for determining the transit time of acoustic energy travel between a transmitter location and a receiver location.

Abstract: The ultrasonic echograph comprises at least one piezoelectric transducer (10, 13) for the transmission and/or reception of an ultrasonic scanning beam (20). With at least one piezoelectric transducer (10) there is associated a random phase screen (11) which is arranged in the ultrasonic scanning beam (20) and which is displaceable with respect to the axis of this beam. Means are provided for the recording of an echographic line e(t) for each position (.alpha.) of said random phase screen. The major technical effect of the presence of the random phase screen in the ultrasonic beam path is the disturbing of the coherence of the wave traversing the screen.Applications can be found notably in medical ultrasonic echography and non-destructive testing of materials.

Abstract: An ultrasonic signal processing system that includes flaw gates that process signals from an inspection transducer is disclosed. The flaw gates operate in pairs where each pair is dedicated to a time window corresponding to, for example, flaw depth or transducer angle. The time window for a pair of flaw gates is indicated by a channel code produced by a timing control unit. One flaw gate in each pair processes incoming digitized transducer signals during a scan to produce reflector indications while the other gate in each pair transfers data from a previous different position scan to a main computer. The main computer determines flaw locations from the reflector indications and transducer positions provided by the flaw gate.

Abstract: An automation control apparatus for determining whether there is an article within a target area, and, if so, whether the article meets certain predefined acceptability criteria. The control apparatus emits a beam of acoustic energy into the target area and receives back the reflected signal from the area. The received signal is then amplified to account for normal attenuation, and the amplified signal is tested to determine whether its transit time or amplitude indicates the presence of an object within the specified area. If an article is present, waveform analysis is performed on the amplified signal to determine the signature of the article, so that the signature may be compared with predetermined acceptable values. If an object is present and the object meets the acceptability criteria to be classified as a desired article, then a positive indication is provided. Conversely, a negative indication is made if an acceptable article is not present.

Abstract: An apparatus for observing a sound field of an ultrasonic wave, including a first unit which determines characteristic values of a medium at each point of a predetermined region by an ultrasonic wave having a sound field of an arbitrary form and a second unit which displays an output of the first unit as two-dimensional or three-dimensional distribution in the predetermined region, and allows control of the form of the sound field of the ultrasonic wave.

Abstract: An acoustic inspection method is disclosed for determining in a catalytic converter monolith substrate whether a ceramic coating was applied in a predetermined amount and uniformly to the surface of exhaust gas passages extending therethrough and whether the ceramic coating is blocking any of the passages. The method includes mounting the substrate in an acoustically sealed structure so as to form a throat communicating a speaker at an entrance end of the coated passages with an empty resonator cavity at an exit end of the coated passages and thereby form a Helmholtz resonator. The speaker is then driven to produce a continuous sound wave through the coated passages into the resonator cavity at a predetermined frequency approximately the natural frequency of the resonator to thereby produce oscillatory sound waves through the coated passages at the same frequency. The substrate is then reversely mounted and the previous step is repeated.

Abstract: A circuit automatically determines the nature of the seabed over which a vessel is passing, indicating via an audible or other warning signal when a fishing vessel is above a type of seabed which might damage the fishing net. The circuit is responsive to an echosounder signal and raises an alarm when a amplitude of the second bottom echo component in the echosounder signal exceeds a selected threshold level. Preferably the analog echosounder signal is subject to threshold discrimination to provide a pulse-form signal which is then processed by a digital logic circuit to isolate the second bottom echo component.

Abstract: An instrument for analyzing the size and charge of aerosol particles employs a dual beam laser Doppler velocimeter to track the motion of a particle while subjecting the particle to a sinusoidal acoustic field and to a pulsed, high voltage electric field. The particle transmitting through the crossed beams of the laser Doppler velocimeter moves with an oscillatory motion due to the acoustic field and, if the particle is charged, it has a horizontal drift parallel to the electric field during the electric pulse. The phase lag of the particle's motion with respect to the acoustic field is measured to determine the aerodynamic diameter of the particle and the velocity and the direction of the drift relative to the polarity of the applied high voltage electric field is used to determine the magnitude and polarity of the electric charge of the particle.

Abstract: Method for the ultrasonic testing of ferritic bodies having a cladding surface, a surface opposite the cladding surface, a cladding disposed on the cladding surface, an ultrasound transmitter radiating from the surface opposite the cladding surface into the body at an angle relative to the cladding surface, and a receiver for receiving reflections emanating from a fault in the body, which includes radiating longitudinal waves from the transmitter into the body at an angle between 70.degree. and 86.degree. relative to the perpendicular.

Abstract: For the detection of defects such as tears or fold lines in banknotes, for example, continuous wave ultrasonic energy is directed by a transmitter to a flow path for the notes and ultrasonic energy reflected from the notes or transmitted through tears or holes in the notes is converted by a receiver into an electric signal. A signal analyzing circuit is responsive to changes in the output of the receiver during the passage of the banknote. In the ultrasonic inspection area, the note may be passed over rollers with flared ends to cause a tear to open and allow the passage of ultrasonic energy. In a reflective system the note may be passed over a roller to cause one or both of the adjacent edges of a tear to leave the roller surface. The electric signal is analyzed for components indicative of a defect; for tear detection, a spike filter and a circuit for distinguishing tear signals from end-of-note signals may be used.

Abstract: There is disclosed an acoustic inspection method for determining whether the actual fluid flow path through a manufactured fluid flow system such as an evaporator core is of a prescribed length and thereby free of such manufacturing errors as cause a shortened or lengthened fluid flow path. The method comprises the steps of passing a test sound wave of predetermined frequency along the actual fluid flow path through the manufactured fluid flow system and comparing the phase angle of the test sound wave at the exit of the actual fluid flow path being inspected with that of a reference sound wave of the same frequency passing along the exactly prescribed fluid flow path length and on the basis that a difference in phase angle indicates that the fluid flow path being inspected is not of the prescribed length.

Abstract: In a method and apparatus for surveying for nodular targets of a grain size of 1 to 15 cm present on the sea floor, pulse waves in each of three frequency ranges of 3 to 4, 10 to 14 and 25 to 50 KHz are radiated onto the sea floor from a ship navigating on the sea. The reflected sound waves of the three frequency pulse waves are received and the reflexibilities of the respective sound waves are measured from the reflected sound pressures and the reflexibilities are composed. The population of the nodular targets is determined from the composed reflexibility and, as required, the grain size of the nodular targets can be determined from at least one of the ratio of the reflexibility of the sound waves of the frequency range of 3 to 4 KHz to the composed reflexibility and the ratio of the reflexibility of the sound waves of the frequency range of 3 to 4 KHz to the reflexibility of the sound waves of range of 25 to 50 KHz.

Abstract: A gauge for measuring variations in distance of a surface relative to a reference by means of phase shifts in a zone of high acoustic impedance. A gauge head is provided with a first orifice for emitting acoustic waves, driven by a reference signal, toward a surface positioned very close to the gauge head, forming a high impedance zone. A second orifice in the gauge head picks up acoustic waves subjected to the zone and these waves are converted to electrical signals for comparison to the reference signal in a phase detector. The phase error between the two signals is indicative of surface distance variations.

Abstract: A sample of material is tested to determine its elastic properties by generating a stress wave from a first transducer and comparing the stress wave received by a second transducer positioned on the opposite side of the sample to the first transducer. The phase shift and attenuation are used to calculate the elastic properties of the material.

Abstract: Apparatus and method employing line-of-sight wave propagation for measurement of various quantities such as velocity and refractivity structure of a transmission medium at selected locations remote from the measuring device.

Abstract: Short bursts of ultrasonic energy are directed through a three-dimensional specimen to determine the spatial distribution of those structures within the specimen capable of affecting the waveform of the energy. Transducers are placed in spaced positions about the periphery of the specimen to measure the affected parameters (such as attenuation and delay time) of the energy as a result of passing through the specimen along paths between the spaced transducers. The output signals containing this transit time and energy absorption information are retained in a data storage device. Through conventional programming techniques, a computer processes the data and calculates a velocity or absorption profile for each path. The profiles are collectively used to reconstruct two-dimensional or three-dimensional images of the specimen.

Abstract: A system for the inspection of the internal nature of a material utilizes an exciting ultrasonic field which is directed at a focal point to be inspected and heats that focal point. An ultrasonic sensing beam is directed through the material and through the heated focal point and is received by a transducer. A differential measurement of a propagation parameter of the sensing beam is accomplished by comparing a burst of its ultrasonic waves through the focal point without the heating effect of the exciting field, with an identical burst of the same duration, amplitude and frequency, but immediately after the heating effect has been accomplished by the exciting field. This system may be used to determine tissue characteristics, internal blood flow, and for other medical diagnostic functions.