Abstract: A system and method for controlling a drilling tool inside a wellbore makes use of projection of optimal rate of penetration (ROP) and optimal controllable parameters such as weight-on-bit (WOB), and rotations-per-minute (RPM) for drilling operations. Optimum controllable parameters for drilling optimization can be predicted using a data generation model to produce synthesized data based on model physics, an ROP model, and stochastic optimization. The synthetic data can be combined with real-time data to extrapolate the data across the WOB and RPM space. The values for WOB an RPM can be controlled to steer a drilling tool. Examples of models used include a non-linear model, a linear model, a recurrent generative adversarial network (RGAN) model, and a deep neural network model.

Abstract: A method includes a step of forming a sacrificial layer on a first film, a step of forming a second film on the sacrificial layer, a step of forming an etching opening that extends through at least one of the first film and the second film so as to communicate with the sacrificial layer, and a step of forming a hollow portion by etching the sacrificial layer using a gas containing a fluorine-containing gas and hydrogen via the etching opening, wherein a composition ratio of silicon to nitrogen in a first region having a face in contact with the sacrificial layer is larger than a composition ratio of silicon to nitrogen in a second region not including the first region.

Abstract: An ultrasonic inspection method of scanning and inspecting an inspection object with ultrasonic waves includes collecting data obtained by scanning the inspection object with ultrasonic signals by using probes configured to transmit and receive the ultrasonic signals to and from the inspection object via a medium that propagates the ultrasonic signals; and processing and synthesizing the collected data. Synthesizing the data includes depicting an image including a surface of the inspection object in a region including pixels partitioned in a grid-like fashion based on the collected data of the ultrasonic signals, and extracting a pixel having maximum pixel intensity from the pixels arranged along a direction perpendicular to an extending direction of the surface of the inspection object in the depicted image to identify a position of the extracted pixel as a surface shape of the inspection object.

Abstract: Optical readers are disclosed in examples herein. An example optical reader including a light source to emit a light beam; and a spot pattern generator to receive the light beam and to generate a two-dimensional spot array from the light beam, the two-dimensional spot array to be directed toward a substrate having nanostructures, the two-dimensional spot array to be sensed to detect a presence or an absence of a substance of interest on the substrate.

Abstract: Changes in tissue stiffness have long been associated with disease. Systems and methods for determining the stiffness of tissues using ultrasonography may include a device for inducing a propagating shear wave in tissue and tracking the speed of propagation, which is directly related to tissue stiffness and density. The speed of a propagating shear wave may be detected by imaging a tissue at a high frame rate and detecting the propagating wave as a perturbance in successive image frames relative to a baseline image of the tissue in an undisturbed state. In some embodiments, sufficiently high frame rates may be achieved by using a ping-based ultrasound imaging technique in which unfocused omni-directional pings are transmitted (in an imaging plane or in a hemisphere) into a region of interest. Receiving echoes of the omnidirectional pings with multiple receive apertures allows for substantially improved lateral resolution.

Abstract: An ultrasonic holography imaging system and method are provided. The ultrasonic holography imaging system includes an ultrasonic transducer array coupled to an analog processing section. The analog processing section is coupled to a digital processing section. The digital processing section generates digital signals to be converted by the analog processing section into analog signals that are transmitted to individual transceiver elements within the ultrasonic transducer array to cause separate ones of the individual transceiver elements to emit ultrasonic waveforms that are differentiated from each other by one or more parameters, including amplitude, frequency, and phase or modulation thereof.

Abstract: A scanning acoustic microscope comprises a structure including a loading portion and a scanning portion, a transducer disposed in the scanning portion and operable to develop ultrasonic energy, and a controller. A driver is responsive to the controller and is capable of moving the transducer along a scan path with respect to a first plurality of parts disposed in the scanning portion as a second plurality of parts are being loaded into the loading portion.

Abstract: A scanning acoustic microscope comprises a structure including a loading portion and a scanning portion, a transducer disposed in the scanning portion and operable to develop ultrasonic energy, and a controller. A driver is responsive to the controller and is capable of moving the transducer along a scan path with respect to a first plurality of parts disposed in the scanning portion as a second plurality of parts are being loaded into the loading portion.

Abstract: A microlithographic projection exposure apparatus includes a projection light source. The apparatus also includes a heating light source for generating heating light which is at least partly absorbed by an optical element. An illumination optical unit directs the heating light onto the optical element such that the heating light has a predefined intensity distribution on an optical surface of the optical element. The illumination optical unit includes a deflection element which is a diffractive optical element or a refractive freeform element. The deflection element simultaneously directs the heating light impinging thereon in different directions.

Abstract: A method of imaging a test subject includes providing one or more moveable sensors to sense an attribute of the test subject (e.g., acoustic pressure), wherein the attribute has a tonal noise component and a broadband noise component. A rotational sensor is provided to sense a rotational velocity of a rotational element of the test subject. Each of the moveable sensors are moved along a path while continuously acquiring test data that is indicative of the rotational velocity of the rotational element, the sensed attribute, the position, and the orientation of each of the moveable sensors. A set of transfer functions corresponding to points in space that have been visited by the moveable sensors are constructed, each of the transfer functions relating the test data of the moveable sensors to the test data of the rotational sensor. A visual representation of the tonal noise component of the attribute in a region adjacent the test subject is produced using the set of transfer functions.

Abstract: An ultrasonic measurement method and an ultrasonic measurement apparatus are capable of performing an inspection for a short time with a high SN ratio and a small variation An ultrasonic measurement method and an ultrasonic measurement apparatus are capable of performing an inspection for a short time with a high SN ratio and a small variation in sensitivity in a process for detecting a defect in all directions at 360 degrees using a matrix array sensor without performing mechanical scanning in all directions, while reducing noise that is caused by a bottom surface echo. An element selecting circuit selects a group of a plurality of ultrasonic transducer elements for transmission from among ultrasonic transducer elements that constitute a two-dimensional array sensor so that the ultrasonic transducer elements for selected for transmission are arranged in line symmetry with respect to a first line symmetric axis to set the group selected for transmission.

Abstract: A method of performing near-field acoustic holography comprises the following steps. Establishing (102) acoustic data representing a set of near-field acoustic holography measurements at a first set of positions. Extrapolating (204) acoustic data using a model-based extrapolation to obtain extrapolated acoustic data relating to a plurality of positions outside the aperture. Applying (108) a spatial frequency transform to the padded acoustic data to obtain data in a spatial frequency domain. Propagating (110) the Fourier transformed acoustic data. Applying (112) a regularization in a wavenumber domain. Performing (114) an inverse spatial frequency transform.

Abstract: The invention may be embodied as a fingerprint scanner having an ultrasonic wave detector, a platen, an ultrasonic wave generator located between the detector and the platen. The invention may be embodied as a method of scanning a finger. One such method includes providing a platen, a detector and a generator, the generator being placed between the platen and the detector. A finger may be provided on the platen, and an ultrasound wave pulse may be sent from the generator toward the finger. The wave pulse may be reflected from the finger, and received at the detector. The received wave pulse may be used to produce an image of the finger.

Abstract: Methods for tracking the identity of die after singulation from a wafer. The product chips and die include a pattern of features formed in a metallization level of a back-end-of-line (BEOL) wiring structure. The features in the pattern contain information relating to the die, such as a unique identifier that includes a wafer identification used to fabricate the die and a product chip location for the die on a wafer. The features may be imaged with the assistance of a beam of electromagnetic radiation that penetrates into a packaged die and is altered by the presence of the features in a way that promotes imaging.

Abstract: A system and method for analyzing a sample is described. The system may include, for example, a light source and a scanning probe microscope probe. The light source may generate a coherent laser beam that is modulated by a waveform of a lower frequency. The modulated laser beam is absorbed by the sample causing thermally induced expansion and resulting in an excitation of acoustic waves. The probe is locally deployed near the sample and detects, in real time, perturbations in the excited acoustic waves to detect surface and buried structures of the sample.

Abstract: An ultrasonic transducer (100) includes a substrate (1) having a first electrode therein or on a surface thereof and a diaphragm (5) having a second electrode therein or on a surface thereof, with a cavity (4) therebetween. Further, at least one beam (7) is provided on a surface or inside of the diaphragm (5) or the second electrode.

Abstract: A method and system for predicting acoustic fields based on generalized moving frame acoustic holography are disclosed. The method includes acquiring a first wavenumber spectrum on a measurement plane according to a moving coordinate system, converting the first wavenumber spectrum to a second wavenumber spectrum on a reference coordinate system using a relative velocity between the measurement plane and a medium, converting the second wavenumber spectrum to a third wavenumber spectrum on a prediction plane using an acoustic wave propagation theory, converting the third wavenumber spectrum to a fourth wavenumber spectrum on a moving coordinate system using a relative velocity between the medium and the prediction plane, and computing acoustic fields on the prediction plane using the fourth wavenumber spectrum.

Abstract: An acoustic hologram imaging system constructed from a machined housing having folded optics. Various surfaces of the housing are machined to provide a precise alignment to the optical members to be connected thereto, such as a mirror, a lens assembly, a light emitting laser diode, a camera, and the like. A three-part lens is described having different materials with different indexes of refraction in order to provide a desired focus of the light. In addition, an optical spatial filter is disclosed in which, according to various embodiments, all, some, or none of the light passing therethrough is attenuated for recording of the optical image of the hologram.

Abstract: A high spatial resolution phase-sensitive technique employs a scanning near field ultrasound holography (SNFUH) methodology for imaging elastic as well as viscoelastic variations across a sample surface. SNFUH uses a near-field approach to measure time-resolved variations in ultrasonic oscillations at a sample surface. As such, it overcomes the spatial resolution limitations of conventional phase-resolved acoustic microscopy (i.e. holography) by eliminating the need for far-field acoustic lenses.

Abstract: The acoustographic dynamic range extending device and method determines thresholds to reach a preset brightness with a test part and without a test part and transforms these thresholds to image data, where the thresholds can be time thresholds obtained with a single driving voltage and can be voltage thresholds obtained with an increasing driving voltage.

Abstract: The receive sensitivity of an ultrasound array transducer structured with a diaphragm electro-acoustic transducer (101) being a basic unit is affected by change in a charge amount with elapsed time due to leakage or the like, which causes drift of the primary beam sensitivity, degradation in the acoustic SN ratio due to a rise in the acoustic noise level, and degradation in the directivity of an ultrasound beam. To addressing this problem, a charge controller (charge monitor 211) is provided to control charge in an electro-acoustic transducer (101). A charge monitoring section (102) monitors the change in the charge amount. When change in the charge amount is small, transmit sensitivity or receive sensitivity is calibrated by a controller (104) by, for example, multiplying a receive signal by a calibration coefficient corresponding to the change amount. Further, when the change in the charge amount is large, for example, charges can be re-emitted from a charge emitter (103).

Abstract: A continuous scanning method employs one or more moveable sensors and one or more reference sensors deployed in the environment around a test subject. Each sensor is configured to sense an attribute of the test subject (e.g., sound energy, infrared energy, etc.) while continuously moving along a path and recording the sensed attribute, the position, and the orientation of each of the moveable sensors and each of the reference sensors. The system then constructs a set of transfer functions corresponding to points in space between the moveable sensors, wherein each of the transfer functions relates the test data of the moveable sensors to the test data of the reference sensors. In this way, a graphical representation of the attribute in the vicinity of test subject can be produced.

Abstract: In one embodiment, a system to characterize an anomaly in a laminate structure comprises a plurality of actuators to generate a wave signal into a structure being evaluated, a plurality of sensors to collect scattered wave data caused by energy of the wave signal being at least partially reflected or scattered by an anomaly, and a structural health monitoring unit. In some embodiments the structural health monitoring unit executes a scatter imaging algorithm to generate three dimensional image data for the anomaly from the scattered wave data, extracts a scatter volume from the from the scattered wave data, and generates a damage volume estimate and a damage depth estimate from the scattered wave data. Other embodiments may be described.

Abstract: A method for generating an image of an anomaly may include generating a pulse wave into a structure being evaluated from each of a plurality of sensors and collecting any scattered wave data caused by the pulse wave impacting an anomaly. The scattered wave data may be collected by the same sensor that generated the pulse wave or by a different sensor. The method may also include identifying any backscattered wave data from a distal edge or border of any anomaly relative to a location of the sensor collecting the scattered wave data. The method may additionally include processing the backscattered wave data from each of the sensors collecting the scattered wave data to generate a two dimensional image of any anomaly. The method may further include presenting the two dimensional image of any anomaly.

Abstract: A method of performing near- field acoustic holography comprises the following steps. Establishing (102) acoustic data representing a set of near-field acoustic holography measurements at a first set of positions. Extrapolating (204) acoustic data using a model-based extrapolation to obtain extrapolated acoustic data relating to a plurality of positions outside the aperture. Applying a spatial frequency transform to the padded acoustic data to obtain data in a spatial frequency domain. Propagating (110) the Fourier transformed acoustic data. Applying (112) a regularization in a wavenumber domain. Performing (114) an inverse spatial frequency transform.

Abstract: A system and method for analyzing a sample is described. The system may include, for example, a light source and a scanning probe microscope probe. The light source may generate a coherent laser beam that is modulated by a waveform of a lower frequency. The modulated laser beam is absorbed by the sample causing thermally induced expansion and resulting in an excitation of acoustic waves. The probe is locally deployed near the sample and detects, in real time, perturbations in the excited acoustic waves to detect surface and buried structures of the sample.

Abstract: A high spatial resolution phase-sensitive technique employs a scanning near field ultrasound holography (SNFUH) methodology for imaging elastic as well as viscoelastic variations across a sample surface. SNFUH uses a near-field approach to measure time-resolved variations in ultrasonic oscillations at a sample surface. As such, it overcomes the spatial resolution limitations of conventional phase-resolved acoustic microscopy (i.e. holography) by eliminating the need for far-field acoustic lenses.

Abstract: In one embodiment, a system to characterize an anomaly in a laminate structure comprises a plurality of actuators to generate a wave signal into a structure being evaluated, a plurality of sensors to collect scattered wave data caused by energy of the wave signal being at least partially reflected or scattered by an anomaly, and a structural health monitoring unit. In some embodiments the structural health monitoring unit executes a scatter imaging algorithm to generate three dimensional image data for the anomaly from the scattered wave data, extracts a scatter volume from the from the scattered wave data, and generates a damage volume estimate and a damage depth estimate from the scattered wave data. Other embodiments may be described.

Abstract: The present invention relates to a method of acquiring an ultrasound image in an ultrasound imaging system having an array transducer, comprising: a) setting an image point at a predetermined depth on an ultrasound image acquired based on a reference speed of sound for a target object; b) setting a range of speed of sound with reference to the reference speed; c) setting a plurality of speeds of sound in a predetermined interval within the range of speed of sound; d) acquiring ultrasound images at each speed of sound; e) calculating an amplitude of an image point set at a predetermined depth of each ultrasound image; f) determining a real speed of sound in the target object based on the calculated amplitude; and g) acquiring an ultrasound image based on the determined real speed of sound in the target object.

Abstract: A high spatial resolution phase-sensitive technique employs a scanning near field ultrasound holography (SNFUH) methodology for imaging elastic as well as viscoelastic variations across a sample surface. SNFUH uses a near-field approach to measure time-resolved variations in ultrasonic oscillations at a sample surface. As such, it overcomes the spatial resolution limitations of conventional phase-resolved acoustic microscopy (i.e. holography) by eliminating the need for far-field acoustic lenses.

Abstract: The invention may be embodied as a fingerprint scanner having an ultrasonic wave detector, a platen, an ultrasonic wave generator located between the detector and the platen. The invention may be embodied as a method of scanning a finger. One such method includes providing a platen, a detector and a generator, the generator being placed between the platen and the detector. A finger may be provided on the platen, and an ultrasound wave pulse may be sent from the generator toward the finger. The wave pulse may be reflected from the finger, and received at the detector. The received wave pulse may be used to produce an image of the finger.

Abstract: A method for examining the interior material of an object, such as a pipeline or a human body, from a surface of an object using ultrasound having a frequency of at least 100 KHz, wherein the ultrasound is supplied to the interior material of the object. The reflections and/or diffractions of the ultrasound from the interior material of the object are received using ultrasonic receivers which are acoustically coupled to the surface of the object at positions which are distributed in two dimensions of the surface of the object, at different points in time or not, wherein, with each of the feelers, a receiving signal is generated, wherein the receiving signals are processed in combination in order to determine, according to the principle of inverse wave field extrapolation, where in the interior material of the object reflections and/or diffractions occur.

Abstract: An ultrasonic transducer (100) includes a substrate (1) having a first electrode therein or on a surface thereof and a diaphragm (5) having a second electrode therein or on a surface thereof, with a cavity (4) therebetween. Further, at least one beam (7) is provided on a surface or inside of the diaphragm (5) or the second electrode.

Abstract: The receive sensitivity of an ultrasound array transducer structured with a diaphragm electro-acoustic transducer (101) being a basic unit is affected by change in a charge amount with elapsed time due to leakage or the like, which causes drift of the primary beam sensitivity, degradation in the acoustic SN ratio due to a rise in the acoustic noise level, and degradation in the directivity of an ultrasound beam. To addressing this problem, a charge controller (charge monitor 211) is provided to control charge in an electro-acoustic transducer (101). A charge monitoring section (102) monitors the change in the charge amount. When change in the charge amount is small, transmit sensitivity or receive sensitivity is calibrated by a controller (104) by, for example, multiplying a receive signal by a calibration coefficient corresponding to the change amount. Further, when the change in the charge amount is large, for example, charges can be re-emitted from a charge emitter (103).

Abstract: A high spatial resolution phase-sensitive technique employs a scanning near field ultrasound holography (SNFUH) methodology for imaging elastic as well as viscoelastic variations across a sample surface. SNFUH uses a near-field approach to measure time-resolved variations in ultrasonic oscillations at a sample surface. As such, it overcomes the spatial resolution limitations of conventional phase-resolved acoustic microscopy (i.e. holography) by eliminating the need for far-field acoustic lenses.

Abstract: Systems and methods for adjusting gain are described. The systems includes a probe. The probe includes a housing, a transducer element configured to receive a signal, and an adjustable gain amplifier located inside the housing and configured to adjust a gain provided to the signal based on a function having a slope other than zero.

Abstract: A high spatial resolution phase-sensitive technique employs a scanning near field ultrasound holography (SNFUH) methodology for imaging elastic as well as viscoelastic variations across a sample surface. SNFUH uses a near-field approach to measure time-resolved variations in ultrasonic oscillations at a sample surface. As such, it overcomes the spatial resolution limitations of conventional phase-resolved acoustic microscopy (i.e. holography) by eliminating the need for far-field acoustic lenses.

Abstract: An acoustical holographic imaging method and apparatus for introducing a reference wave into a hologram surface such that the reference wave does not interfere with an object placed adjacent to or in close proximity to the hologram surface. More particularly, the ultrasonic holographic imaging system may use a reference wave introduced on the side of a thin (3 element) detector that acts as a wave guide; to introduce the reference wave to a liquid-to-gas interface or alternatively, from the topside of the detecting surface through a liquid-to-liquid interface. The system eliminates the acoustic lens system, thereby reducing the size and cost of the system. Further, an object may be placed at the detecting surface, increasing the depth of field of the resultant image and reducing the energy needed from the object source. The system may additionally utilize multiple reference sources.

Abstract: To reduce the cost while maintaining the real time environment in receiving ultrasonic waves in an ultrasonic receiving apparatus which is capable of reducing changes in detection sensitivity due to environmental changes in the ultrasonic detecting element. The ultrasonic receiving apparatus comprises a light source for generating broadband light, an ultrasonic detecting element including an ultrasonic sensing portion that expands and contracts in response to a received ultrasonic wave and has optical reflectance that changes in accordance with expansion and contraction thereby performing intensity modulation on the light, spectrum-separating means for spectrum-separating the light, first photo-detecting means having a plurality of photoelectric conversion elements for detecting the light for plural wavelength components, and second photo-detecting means for detecting a selected wavelength component included in the light on the basis of a detection result of the first photo-detecting means.

Abstract: There is disclosed an improved ultrasonic hologram or other ultrasonic imaging process that accurately forms phase and amplitude information of the hologram in a manner that renders the unit relatively insensitive to environment vibrations, and provides long maintenance free functioning lifetime. Specifically, there is disclosed an improved ultrasonic hologram detector component that forms an ultrasonic hologram on the surface of a detection deformable detector material, resulting from the deformation of the surface. The surface deformation is due to the reflection of an ultrasound (ultrasonic) energy profile of the combination of an “object wave” that passes through an object and that of a “reference wave” that is directed to the surface at an off axis angle from the “object wave”.

Abstract: An improved scanning station and method for a tray-fed scanning acoustic microscope has a vacuum system which at least assists in immobilizing loosely held parts in the trays during insonification by an ultrasonic beam generator.

Abstract: A method and apparatus for generating an acoustic holographic image having a plurality of pulses with different characteristic parameters from each other. More particularly, a sequence contains a plurality of pulses which have different characteristic parameters from each other. An image is created for each sequence and the effect of each pulse in creating the image is varied based on the variation of the characteristic parameter for each pulse. A selectively enhanced acoustic image is thereby obtained.

Abstract: An optical detection type ultrasonic receiving apparatus in which S/N ratio of the detection signal is increased while preventing the apparatus from increase of size and cost. The ultrasonic receiving apparatus includes a light source for generating broadband light, an ultrasonic detecting element including an ultrasonic sensing portion to perform intensity modulation of the light, a spectrum-separating unit for spectrum-separating the modulated light, a photo detecting unit having a plurality of photoelectric converting elements for detecting the spectrum-separated light for each of plural wavelength components to generate at least a first detection signal of a first wavelength component and a second detection signal of a second wavelength component, and processing unit for carrying out processing operation using the first detection signal and the second detection signal to obtain information about the ultrasonic wave received by the ultrasonic detecting element.

Abstract: The contents of a container 1 are non-intrusively monitored by probing the container with an ultrasonic signal, and measuring changes in the ultrasound signature of the received signal after the signal has passed through the contents of the container.

Abstract: An acoustoelectronic method and apparatus for generating real-time three-dimensional images of an object and characterizing such object are provided. The object is insonified with an incident acoustic signal derived from an electrical signal. Acoustic signals scattered from the object are collected by an acoustic receiver, which generates analog electrical signals that are subsequently converted to digital electronic signals. The digital electronic signals are used in both direct-imaging and holographic methods to produce a three-dimensional representation of the object from which images and characterizations can be generated.

Abstract: There is disclosed a series of process and apparatus modifications to ultrasonic holography imaging systems that each or together function to enhance image quality of ultrasonic holography images. Specifically, there is disclosed a process and apparatus for generating multiple exposure ultrasonic holography images generated from selected orientations, each of which insures multiple images, multiple intensities (amplitudes) and multiple frequencies from each orientation. The inventive process and apparatus for providing multiple view, multiple angle, and multiple frequency or intensity transmissive ultrasound imaging of the internal structures of an object provides an object sound intensity of equal or near equal intensity across the entire field of the object, such as a human breast.

Abstract: An automated acoustic micro imaging system includes a part-storage station favoring a dry environment, a part-transport robot, and a wet-environment inspection station. The wet-environment inspection station has an ultrasonic beam generator, a coupling fluid in which parts are inspected, and a part-retention stage. A moisture barrier is located between the wet-environment inspection station and the part-storage station favoring a dry environment. The inspection station includes a kinematic, quick-change part-retaining chuck and robotic means for interchanging chucks. Automatic acoustic micro imaging methods are disclosed.

Abstract: There is disclosed an improved ultrasonic hologram or other ultrasonic imaging process that accurately forms phase and amplitude information of the hologram in a manner that renders the unit relatively insensitive to environment vibrations, and provides long maintenance free functioning lifetime. Specifically, there is disclosed an improved ultrasonic hologram detector component that forms an ultrasonic hologram on the surface of a detection fluid, resulting from the deformation of the surface. The surface deformation is due to the reflection of an ultrasound (ultrasonic) energy profile of the combination of an “object wave” that passes through an object and that of a “reference wave” that is directed to the surface at an off axis angle from the “object wave”.

Abstract: Disclosed is a system for testing liquid crystal and end seal of liquid crystal displays. In the present invention, a test unit P for liquid crystal distribution is disposed at a side of a loading unit L. The test unit P for liquid crystal distribution is disposed orthogonal to a test unit G for end seal. Unloading units Ug, Ur, Uj of good, repair, reject are disposed in parallel by a selected distance. A robot unit R one by one to the respective testing units, is disposed between the loading and unloading units L,U. An operating panel S is installed between the test units P,G according to the test result and a monitor M displaying the liquid crystal injecting hole is installed at the operating panel S. Furthermore, the investigator may conduct two tests for liquid crystal and for end seal simultaneously at one position in front of the operating panel S.

Abstract: An ultrasonic inspection system for inspecting a test object and producing substantially artifact-free images, which system includes (1) a sound source for emitting ultrasonic energy toward a test object, (2) a liquid crystal detector for detecting emitted ultrasonic energy and displaying an image, and (3) a coupling medium for sonically coupling the sound source, the test object and the detector. The ultrasonic energy is emitted at each of a plurality of frequencies within a predetermined range. It has been determined that the ultrasonic energy insonifing the object can be caused to scan the object and be angularly varied with respect thereto. Moreover, the rate of frequency scanning is substantially less that the detector image decay so as to produce a substantially flicker-free image. The angular variation is performed by rocking the sound source through a small angle, such as 2.degree. to 6.degree. relative to the liquid crystal detector.