Abstract: Methods and devices for imaging wells using ultrasound is described. The devices include a modular imaging device having a telemetry module and a radial imaging module and/or forward imaging module. The radial imaging module includes a ring shaped phased array ultrasonic transducer array for generating images on the length of a wellbore. Various lens and housing configurations for the radial imaging module are described. The forward imaging module includes an ultrasonic transducer comprising one or more elements and having an adjustable viewpoint for generating images of obstructions found in a wellbore. Advanced imaging modes for a radial imaging module include multiple aperture and spiral wave imaging mode.

Abstract: A method for locating an underwater acoustic source includes using first and second linear arrays to receive signals. These signals can be resolved into intersecting cones and a contour of possible source locations can be estimated. In further embodiments, a third sonar array can receive a bearing and a depression/elevation from a signal. This information can be used with the contour to estimate a source location.

Abstract: A lens system may include a lens having a first electrode electrode layer, a second electrode layer, and a liquid crystal layer disposed between the first electrode layer and the second electrode layer. The lens may be divided into a plurality of lens segments that are concentrically arranged proceeding from a center to a radially outer periphery of the lens. An optical power of a first lens segment of the plurality of lens segments may be greater than an optical power of a second lens segment of the plurality of lens segments disposed radially outward relative to the first lens segment. Various other devices, systems, and methods are also disclosed.

Abstract: A method and system are described for examining the interior material of an object from a surface of an object, using ultrasound having a frequency of at least 100 kHz. The method comprises the step of transmitting at least a first ultrasound signal by a first ultrasound transmitter of a first number of ultrasound transmitters to the interior material of the object for forming a first image in order to determine, according for example to the principle of inverse wave field extrapolation, where in the interior material of the object reflections and/or diffractions occur. Reflections and/or diffractions of the first ultrasound signal from the interior material of the object are received using a second number of ultrasound receivers which are acoustically coupled to the surface of the object at positions which are distributed in at least one dimension of the surface of the object.

Abstract: A global active noise control method for a rotorcraft, including: acquiring the acoustic pressure signal at a measuring point of the rotorcraft; predicting the holographic and global sound field of noise of the rotor; reconstructing the reverse sound field of the noise of the rotor; and performing adaptive sound field adjustment based on the optimal phase search.

Abstract: A transducer array (802) includes at least one 1D array of transducing elements (804). The at least one 1D array of transducing elements includes a plurality of transducing elements (904). A first of the plurality of transducing elements has a first apodization and a second of the plurality of transducing elements has a second apodization. The first apodization and the second apodization are different. The transducer array further includes at least one electrically conductive element (910) in electrical communication with each of the plurality of transducing elements. The transducer array further includes at least one electrical contact (906) in electrical communication with the at least one electrically conductive element. The at least one electrical contact concurrently addresses the plurality of transducing elements through the at least one electrically conductive element.

Abstract: Various embodiments include determining a level of a surface of a fluid and/or for determining a quality of the fluid in a fluid container. An example apparatus comprises a sound transducer module having two sound transducers designed to receive and emit sound signals in such a manner that a superimposition sound signal results when the sound signals are superimposed, and a reference element arranged in the fluid at a predefined distance from the sound transducer module and is designed to reflect the superimposition sound signal. The sound transducer module is designed, by superimposing the at least two sound signals, to emit the superimposition sound signal both in a first direction to the surface of the fluid and in a second direction to the reference element, said second direction running at a predetermined sound signal angle with respect to the first direction.

Abstract: In an image compressing ultrasound system, for generating an imaging sample, delays are applied transducer-element-wise to respective time samples. The delayed samples are summed coherently in time, the coherently summed delays being collectively non-focused. An image is sparsified based on imaging samples and, otherwise than merely via said imaging samples, on angles (236) upon which respectively the delays for the generating of the imaging samples are functionally dependent. An image-compressing processor (120) may minimize a first p-norm of a first matrix which is a product of two matrices the content of one representing the image in a compression basis. The minimizing is subject to a constraint that a second p-norm of a difference between a measurement matrix and a product of an image-to-measurement-basis transformation matrix, an image representation dictionary matrix, and the matrix representing the image in the compression basis does not exceed an allowed-error threshold.

Abstract: A device for determining a height of soil above a structure buried below a soil bed includes a sensor assembly comprising a total stress pressure sensor for transmitting a first signal indicating a total pressure, a pore water pressure sensor located proximate to the total stress pressure sensor, the pore water pressure sensor for transmitting a second signal indicating a fluid pressure, a sensor module configured to receive the first and the second signals, determine a difference between the first signal and the second signal, based on the difference between the first signal and the second signal, determine a height of soil above the sensor assembly, and transmit a third signal indicating the height of soil to an external device.

Abstract: A widget browser module configured to display data item descriptors is disclosed. The widget browser module is configured to: generate, responsive to a request from an executing application that is causing the display of an application window on a display device, a widget browser window for display over a portion, but not all, of the application window, the widget browser window including a two-panel display window and a status bar display window positioned underneath the two-panel display window; display a plurality of sibling data item descriptors in a first panel of the two-panel display window that are contextually relevant to content in the application window; and display, after selection of a data item descriptor, the selected data item descriptor and sibling data item descriptors in the first panel and child data item descriptors of the selected data item descriptor in a second panel of the two-panel display window.

Abstract: A sensor 30 including a plurality of elements 31 is divided into a plurality of regions 1 and 2. A UT device 20 is connected to each region of the sensor 30 via a switch 40. At least one region of the sensor 30 used for UT is selected for each flaw detection point according to a positional relation of the flaw detection point to the sensor 30. The UT device is connected to the selected at least one region of the sensor 30 by the switch 40. For a flaw detection point for which one region is selected, UT is performed by using the selected one region. For a flaw detection point for which a plurality of regions are selected, a necessary number of times of ultrasonic testing are performed according to a number of the regions by using the selected plurality of regions, and the results are subjected to addition processing.

Abstract: A delay line control circuit includes a pseudo-random number generator and a random phase generator circuit coupled to the pseudo-random number generator. The pseudo-random number generator is configured to produce a predetermined sequence of pseudo-random values. The random phase generator circuit is configured to randomize an access sequence for capacitors of a delay line. The random phase generator circuit includes a sequence register, an adder, and gating circuitry. The sequence register is configured to a store a value identifying one of the capacitors to be accessed. The adder is coupled to the sequence register, and is configured to increment the value stored in sequence register. The gating circuitry is coupled to the pseudo-random number generator and the adder. The gating circuitry is configured to pass one of the pseudo-random values to the adder for addition to the value stored in the sequence register.

Abstract: An ultrasonic imaging apparatus includes an ultrasonic probe and a delay amount calculation unit. Each of the delay circuits is configured to allow a first delay amount and a second delay amount to be set for each of the delay circuits, and delays a signal by a delay amount obtained by adding the first delay amount and the second delay amount together. The delay amount calculation unit calculates the first delay amount and the second delay amount such that a sum of the first delay amount and the second delay amount set for each of the delay circuits is equal to or less than a predefined maximum delay amount.

Abstract: Techniques are disclosed for systems and methods to provide intuitive user interfaces for sonar systems attached to mobile structures. A sonar user interface system includes a logic device configured to communicate with one or more sonar controllers and/or sonar transducer assemblies and associated processing and control electronics and optionally orientation and/or position sensors disposed substantially within the sonar transducer assemblies. Each sonar controller and/or transducer assembly includes channels that can be operated together or independently. Configurations for each channel, transducer assembly, controller, and/or for the entire sonar system are rendered and displayed using a combination of graphical and textual indicators to allow intuitive selection and/or arrangement of system, controller, assembly, and/or channel configurations and to store configurations for recall.

Abstract: An ultrasound system (10) which is capable of biplane imaging is able to display, store and export independent image frames of only the reference image or only the variable orientation image, or the standard display of both images. The system is also able to sweep through a range of image plane orientations and to automatically acquire an image in each orientation over the range of plane orientations. The system is preferably operable in the biplane tilt mode, the biplane rotate mode, or the biplane elevation tilt mode.

Abstract: Methods, apparatuses, and computer program products are therefore provided for producing a 3D image of an underwater environment. An example method for providing an image of an underwater environment includes analyzing sonar returns to identify and display objects, such as fish or debris, in a 3D view. Such an image allows for differentiation between the sea floor and objects in a 3D sonar view. Some example methods provide for real-time tracking of fish. Further, the fish or other objects may be displayed over a continuous surface geometry based on sonar returns from a lake, sea, or river “floor.

Abstract: The invention relates to a method for determining the direction of a source of waterborne sound that emits a waterborne acoustic signal, by means of a hydrophone arrangement which forms a linear antenna or a virtual linear antenna, as well as to a computer program product, a computer, a sonar, and a watercraft.

Abstract: A portable ultrasonic imaging probe that is adapted to connect to a host computer via a passive interface cable. The probe includes an array of ultrasound transducers, a high voltage pulser for energizing transducers to emit an ultrasound pulse, analog signal processing circuitry that combines echoes detected by transducers into a single analog echo signal, am analog-to-digital converter that converts the analog echo signal into a digital echo signal; and interface circuitry that transfers the digital echo signal across the passive interface cable to the host computer. The probe includes transmit switches configured to selectively connect sets of ultrasound transducers to the HV pulser and a plurality of receive switches configured to selectively connect sets of ultrasound transducers to the analog signal processing circuitry.

Abstract: An ultrasonic probe includes a multi-dimensionally arrayed transducer, a matching layer, and a backing layer. The transducer includes element groups having different focal distances and simultaneously transmitting ultrasonic signals toward an object. According to the ultrasonic imaging apparatus using the multi-dimensionally arrayed transducer, a multi-focus transmission is performed. Thus, the multi-focus ultrasonic image may be acquired within a short period of time, thereby increasing frame rates, and a high-quality image in which all areas are focused may be quickly acquired.

Abstract: Methods, apparatuses, and computer program products are therefore provided for producing a 3D image of an underwater environment. An example method for providing an image of an underwater environment includes analyzing sonar returns to identify and display objects, such as fish or debris, in a 3D view. Such an image allows for differentiation between the sea floor and objects in a 3D sonar view. Some example methods provide for real-time tracking of fish. Further, the fish or other objects may be displayed over a continuous surface geometry based on sonar returns from a lake, sea, or river “floor.

Abstract: An array of piezoelectric ultrasonic transducer elements includes a plurality of superpixel regions. Each superpixel region includes at least two pixel sets, a first pixel set of the at least two pixel sets being disposed in a central portion of the superpixel region, and at least a second pixel set being disposed in an outer portion of the superpixel region. An electrical coupling may be provided between the array and transceiver electronics. The transceiver electronics may be configured to operate the array in a selectable one of a first mode and a second mode. In the first mode, the array generates a substantially plane ultrasonic wave having a first acoustic pressure. In the second mode, the array generates, from each superpixel region, a focused beam having a second acoustic pressure that is substantially higher than the first acoustic pressure.

Abstract: A system for small space positioning comprises a transmitting element at a fixed and known location, which transmitting a modulated continuous wave, for example an ultrasonic wave, having a continuous carrier signal part and a base-band signal modulated thereon. The transmitting element transmits the modulated continuous wave over a range in which an object to be positioned may appear. A receiving element receives signals transmitted by the transmitting device and reflected by the object, and a position detection element determines a position of the object from analysis of both the carrier signal part and the base-band signal received from the reflected signal.

Abstract: This disclosure provides wave-powered vessels equipped for fish stock management. The vessels have observational sensors for monitoring fish, a positional sensor to determine the geographical location of the vessel, and a transmitter for sending data to a central control unit. The observational sensors may be deployed on a tow body pulled behind the vessel, or the tow body may relay information from sensors located on a separate unit on the bottom or at a defined depth. The control unit communicates with each of the monitor vessels to direct navigation and obtain data from the sensors. Substance distribution vessels in the fleet are equipped to distribute fish food in target area for the purpose of fish farming.

Abstract: A communication apparatus includes an output portion and a controller. The output portion outputs an output signal. The output signal includes a synchronization signal, a data signal, and an end signal in this order. The controller includes a measuring portion that measures a length of a received pulse, a signal determiner that determines whether the received pulse corresponds to the synchronization signal based on the length of the received pulse, and a signal acquisition portion. The signal acquisition portion skips the received pulse in a case where the signal determiner determines that the received signal does not include the synchronization signal. The signal acquisition portion considers the received signal as the synchronization signal and reads a pulse following the received pulse to the end signal in a case where the signal determiner determines that the received signal includes the synchronization signal.

Abstract: An ultrasound imaging system and method includes identifying, with a processor, a subset of the ultrasound channel data with a specular reflector signature, and implementing, with the processor, a specular reflector processing technique on the subset of the ultrasound channel data to calculate at least one of a position and an orientation of a specular reflector. The system and method includes performing an action based on at least one of the position and the orientation of the specular reflector.

Abstract: A method and towed sonic array system for defocusing the beampattern of the towed sonic array. The method includes determining an amplitude adjustment and a phase adjustment for each of the sonic projectors; and driving each of the sonic projectors with a drive signal modified by the amplitude adjustment and the phase adjustment for that sonic projector. The amplitude adjustment and phase adjustment for each of the sonic projectors are, at least in part, based upon the distance from that sonic projector to a virtual source. The location of the virtual source may be selected so as to achieve different beampatterns, including wide-sector beams and, in at least one case, a near-omni-directional beampattern. The drive signal may include multiple frequency components, in which case the method may be used to find a set of beamformer coefficients for each of the frequency components and an inverse transform may be used to realize a defocused driving signal.

Abstract: An ultrasonic flaw detector including an ultrasonic probe for emitting an ultrasonic wave on an object to be inspected and receiving a reflected ultrasonic wave from the object, a drive element control unit for controlling a plurality of ultrasonic elements to emit an ultrasonic wave from the ultrasonic probe and to control a reflected ultrasonic wave from the object, and a calculation unit for obtaining, by using a refraction angle of the ultrasonic wave at a time of the ultrasonic wave entering the object, an incident position of the ultrasonic wave on a surface of the object, and a surface shape of a surface of the object at the incident position, the incident angle of the ultrasonic wave entering the incident position, and obtaining a plurality of ultrasonic elements to be driven, based on the incident position and the incident angle.

Abstract: A receiver with orthogonal beam forming technique is achieved that is capable of differentiating different signal components within the received composite signal. An adaptive processor is used to eliminate the signal component whose phase information is known or can be calculated. The phase information of the major component of a signal can be easily acquired by using a limiter. The phase information of other signal components can be acquired by their direction information and other characteristics, such as modulation scheme, etc. Multiple orthogonal beams can be formed by eliminating one unwanted signal component each time by the adaptive processor until all unwanted signal is eliminated. Thus, a composite signal from multiple sources can be broken down into their component signals.

Abstract: An ultrasonic transducer device includes an ultrasonic transducer element array, a first signal terminal and a second signal terminal. The ultrasonic transducer element array has a 1st element group to a kth element group (where k is a natural number such that k?2). The first signal terminal is connected with a control section configured to perform at least one of receiving and transmitting of signals. The second signal terminal is connected with the first signal terminal via the ultrasonic transducer element array. Each of the 1st element group to the kth element group includes a plurality of ultrasonic transducer elements electrically connected in parallel. The 1st element group to the kth element group are electrically connected in series between the first signal terminal and the second signal terminal.

Abstract: An ultrasonic transducer device includes an ultrasonic transducer element array, a first signal terminal, and a second signal terminal. The ultrasonic transducer element array has a 1st element group to a kth element group (where k is a natural number such that k?2). The first signal terminal is connected with a control section configured and arranged to perform at least one of receiving and transmitting of signals. The second signal terminal is connected with the first signal terminal via the ultrasonic transducer element array. Each of the 1st element group to the kth element group includes a plurality of ultrasonic transducer elements electrically connected in series. The 1st element group to the kth element group are electrically connected in parallel between the first signal terminal and the second signal terminal.

Abstract: An ultrasound transmission circuit comprises a pulse generating circuit, a feedback circuit and a processing circuit. The feedback circuit outputs a trigger signal according to a first pulse signal arriving at an ultrasound transducer. The processing circuit records a first time point at which the first pulse signal is generated, and records a second time point at which the first pulse signal arrives the ultrasound transducer according to the trigger signal. The processing circuit adjusts a first delay value according to a variance between the first time point and the second time point to generate a second delay value, and drives the pulse generating circuit according to the second delay value to generate a second pulse signal.

Abstract: An acoustic pretouch sensor or proximity sensor (110) includes a cavity (104) with a first microphone (106) disposed therein, and optionally a second microphone (108) disposed outside of the cavity. A processing system (110) receives the signals generated by the first microphone and analyzes the spectrum to produce a result representing the resonant frequency of the cavity. The processing system may optionally subtract the second microphone signal spectrum from the first to automatically compensate for changes in ambient noise. The processing system uses the resonant frequency to estimate the distance from the cavity opening to a surface (90). For example, the pretouch sensors may be incorporated into a stand alone device (100), into a robotic end effector (204), or into a device such as a phone (300).

Abstract: An ultrasonic transducer device includes an ultrasonic element array and a common electrode wiring. The ultrasonic element array has three ultrasonic element rows with each of the three ultrasonic element rows including a plurality of ultrasonic elements arranged along a first direction and electrically connected to each other. The three ultrasonic element rows are arranged along a second direction intersecting with the first direction. The common electrode wiring is configured and arranged to supply a common voltage to at least one of the three ultrasonic element rows. The common electrode wiring extends in the first direction and is arranged between two of the three ultrasonic element rows positioned on outer sides among the three ultrasonic element rows with respect to the second direction.

Abstract: A system for small space positioning comprises a transmitting element at a fixed and known location, which transmitting a modulated continuous wave, for example an ultrasonic wave, having a continuous carrier signal part and a base-band signal modulated thereon. The transmitting element transmits the modulated continuous wave over a range in which an object to be positioned may appear. A receiving element receives signals transmitted by the transmitting device and reflected by the object, and a position detection element determines a position of the object from analysis of both the carrier signal part and the base-band signal received from the reflected signal.

Abstract: A system is employed for defining a position (location) of a receiving element inside an area surrounded by a wire loop, along the perimeter (a perimeter wire loop), of a work area or other bounded area. In particular, the system can determine whether the receiver is inside or outside the loop, and evaluate its distance from the perimeter wire.

Abstract: A beamforming apparatus is provided for improving beamforming accuracy by employing fractional delay filters in an interpolation process and reducing hardware complexity by using post-filtering technique. The beamforming apparatus of the present invention includes a post-filtering means implemented with fractional delay filters that combines block data, on the respective channels, supposed to be fractionally delayed and obtains a delay value of fractional part from the combined data. The post-filtering means collects the block data of the channels assigned identical coefficients and performs a filtering process simultaneously.

Abstract: A system is employed for defining a position (location) of a receiving element inside an area surrounded by a wire loop, along the perimeter (a perimeter wire loop), of a work area or other bounded area. In particular, the system can determine whether the receiver is inside or outside the loop, and evaluate its distance from the perimeter wire.

Abstract: A method for Fresnel zone imaging is provided. The method comprises identifying a plurality of constructive regions and a plurality of destructive regions in an energy transmitting device and converting the destructive regions to the constructive regions by using an apodization profile. The apodization profile comprises apodization values for each constructive region and destructive region and the apodization values comprise real numbers.

Abstract: A medical diagnostic ultrasound system comprises several subsystems, such as a transmit beamformer, a receive beamformer, a B-mode processor, a Doppler processor and a scan converter. These subsystems are within the ultrasound data processing path for processing ultrasound data. One or more of these subsystems are implemented with one or more re-programmable logic devices. For example, one or two field programmable gate arrays are used is each subsystem to perform most or almost all of the subsystems essential functionality.

Abstract: A transducer senses repetitive pulses on a magnetostrictive element and provides transducer output bursts. A transducer circuit detects the transducer output bursts. An energy storage device couples to a power input of the transducer circuit. A switching power supply couples to the energy storage device and has repetitive suppressed states during which switching in the switching power supply is suppressed. A sequence circuit provides synchronization of the repetitive suppressed states of the switching power supply with the transducer output bursts.

Abstract: A method for real-time computation of point-by-point apodization coefficients used for beam-forming includes storing apodization coefficients of receiving focus points in memory, and computing at least one of an included angle between a vector from a transducer element to a receiving point and a normal vector of the transducer element, and a trigonometric function value of the included angle. The method also includes addressing the memory storing the apodization coefficients according to the quantized included angle or trigonometric function value, and reading the apodization coefficients. In one embodiment, the method may include computing in advance apodization coefficients of a receiving focus point as the starting point for the subsequent interpolation operation and another receiving focus point as the ending point, and deriving, for each receiving channel, apodization coefficients of the points situated between these two receiving focus points through an interpolation operation.

Abstract: An ultrasonic apparatus is disclosed that includes a transducer having a plurality of transducer elements, a controller operatively connected to the transducer and driving the transducer elements to produce a first ultrasonic transmitting beam having a first frequency and a second ultrasonic transmitting beam having a second frequency; and a processor operatively connected to said transducer for forming and moving reception beams to receive echo signals and extracting frequency components corresponding to said first ultrasonic transmitting beam and said second ultrasonic transmitting beam.

Abstract: A device comprising an array of sensors that are reconfigurable by means of a switching network. The sensors may be optical, thermal or pressure sensors or ultrasonic transducers.

Abstract: The present invention presents a method for use with an acoustic sensor array comprised of a number of pressure-vector sensors capable of sensing the acoustic scalar field and acoustic vector field of an acoustic wave. The method is a signal processing technique that utilizes nonlinear processing of pressure-vector sensor signals in the acoustic sensor array. The method involves the steps of receiving the sensor output values, processing the output values using a non-linear algorithm to create a mathematical series of values, transforming the series, applying weighting to the series and performing a summation of the values in the series to calculate the array directivity response. The array directivity response can then be further processed where the array is part of a sonar system.

Abstract: An integrated switch matrix for reconfiguring subelements of a mosaic sensor array to form elements. The configuration of the switch matrix is fully programmable. The switch matrix includes access switches that connect subelements to bus lines and matrix switches that connect subelements to subelements. Each subelement has a unit switch cell comprising at least one access switch, at least one matrix switch, a respective memory element for storing the future state of each switch, and a respective control circuit for each switch. The access and matrix switches are of a type having the ability to memorize control data representing the current switch state of the switch, which control data includes a data bit input to turn-on/off circuits incorporated in the control circuit. The sensor array and the switching matrix may be built in different strata of a co-integrated structure or they may be built on separate wafers that are electrically connected.

Abstract: An ultrasonic imaging apparatus and method combines dynamically focused reception and coded transmission/reception technologies by inexpensive circuitry. A receive aperture is divided into smaller apertures. Correspondingly, a receive beam former is divided into receive sub-beam formers 36a to 36n by which a phase alignment and summing process is performed. Thereafter, coded signals are compressed in decoders 37a to 37n in a time axis direction. Output signals from the decoders are once again subjected to a phase alignment and summing process in a second beam former.

Abstract: An integrated high-voltage switching circuit includes a switch having ON and OFF states and having a parasitic gate capacitance. The switch consists of a pair of DMOS transistors integrated back to back and having a shared gate terminal, the drains of the DMOS transistors being connected to the input and output terminals of the switch respectively. The switching circuit further includes a turn-on circuit comprising a PMOS transistor having its drain connected to the shared gate terminal of the switch via a first diode, having its source connected to a global switch gate bias voltage terminal from which the PMOS transistor draws current, and having its gate electrically coupled to a switch gate control terminal that receives a switch gate control voltage input.

Abstract: Signals entered from receiving transducer elements of 160 channels are multiplexed into 10 signal lines by 10 multiplexers. Each of 10 A/D converters converts the signals of 16 channels from analog from into digital form. The multiplexers are switched with synchronized switching timing to produce 10 pieces of sample data strings with the same timing. 160 pieces of sample data sampled in a steplike form are shifted in phase according to an oblique-line sampling scheme. The signal of the same channel is sampled twice with a phase delay of 90° so that the signal can be converted into complex-valued sample data without increasing the number of processing circuits.

Abstract: An apparatus and method for scanning a body of water for fish and other underwater articles with a sonar depth finder of a type having a transducer that can transmit an acoustic wave and receive sonar returns on both a narrow acoustic wave beam mode and on a wide acoustic wave beam mode, in which the sonar depth finder repetitively determines the approximate depth of the body of water by repetitively transmitting in the wide beam mode and receiving and displaying the sonar returns from each transmission initially in the wide beam mode and then in the narrow beam mode, with the duration of receiving in the narrow acoustic wave beam mode being a function of the determined depth from a prior transmission.

Abstract: An acoustic imaging apparatus and method that achieves desired delays with coded signals. Linear, curved linear and sector scanning is provided in 1-D arrays and planar, curved planar and sector scanning is provided in 2-D arrays. Composite and non-linear implementations are presented. Dynamic and discrete dynamic focusing is disclosed for the relevant arrays. The 2-D array makes possible 3-D imaging.