Abstract: Example sonar transducer assemblies configured for reduced interference are provided herein. An example sonar transducer assembly includes a housing, a first transducer, and a second transducer. The first transducer is positioned within the housing such that a length is configured to extend in a first mounting plane and a produced first beam defining a fan-shape extends in a first plane. The second transducer is positioned at a tilted angle within the housing such that a length is configured to extend in a second mounting plane and a produced second beam defining a fan-shape is in a second plane. The second mounting plane is non-parallel to the first mounting plane and is offset from the first mounting plane by at least 1 degree such that the second plane is not parallel to the first plane so as to reduce interference between the first transducer and the second transducer.

Abstract: A coprime microphone array (CMA) system, comprising: a CMA arrangement that includes a pair of uniform linear microphone subarrays that are coincident and have a coprime number of microphones; a computing system that processing signals from each microphone in the CMA arrangement and generates sound localization information.

Abstract: A microphone module comprises a housing, an audio bus, and a first plurality of microphones in communication with the audio bus. The microphone module further comprises a module processor in communication with the first plurality of microphones and the audio bus. The module processor is configured to detect the presence of an array processor in communication with the audio bus, detect the presence of a second microphone module in communication with the audio bus, and configure the audio bus to pass audio signals from both the first plurality of microphones and the second microphone module to the array processor.

Abstract: Provided are method, system, and computer program product for imaging an underwater environment. The method may include receiving sonar returns and converting the sound energy of the sonar returns into sonar return data, and generating first beam data associated with a first beam having at least one first main lobe oriented in a first direction. Generating the first beam data may include: forming the sonar return data in the first direction; applying a first predetermined window to the sonar return data to define a first weighted return data; applying a second predetermined window to the sonar return data to define a second weighted return data; comparing a first power of the first weighted return data to a second power of the second weighted return data; and defining, when the first power is less than the second power, the first beam data based upon the first weighted return data.

Abstract: Disclosed are systems and methods for focusing ultrasound transducers that include multiple separate, independently movable transducer segments.

Abstract: Systems and methods are provided for applying flux to a quantum-coherent superconducting circuit. In one example, a system includes a long-Josephson junction (LJJ), an inductive loop coupled to the LJJ and inductively coupled to the quantum-coherent superconducting circuit, and a single flux quantum (SFQ) controller configured to apply a SFQ pulse to a first end of the LJJ that propagates the SFQ pulse to a second end of the LJJ, while also applying a flux quantum to the inductive loop resulting in a first value of control flux being applied to the quantum-coherent superconducting circuit.

Abstract: The disclosed embodiments include a method, system, and device for conducting ultrasound interrogation of a medium. The novel method includes transmitting a non-beamformed or beamformed ultrasound wave into the medium, receiving more than one echoed ultrasound wave from the medium, and converting the received echoed ultrasound wave into digital data. The novel method may further transmit the digital data. In some embodiments, the transmitting may be wireless. The novel device may include transducer elements, an analog-to-digital converter in communication with the transducer elements, and a transmitter in communication with the analog-to-digital converter. The transducers may operate to convert a first electrical energy into an ultrasound wave. The first electrical energy may or may not be beamformed. The transducers also may convert an echoed ultrasound wave into a second electrical energy.

Abstract: A system for determining the distance from and the direction to an object includes an emitter and at least two receiver elements for receiving a signal which is transmitted by the emitter and reflected by the object. The receiver elements are arranged as a linear array, as two linear arrays situated at an angle to one another, as an array which surrounds the emitter and forms a circle, or as a two-dimensional array. The diameter of the array may be greater than one-half the wavelength of the signal, and the receiver elements each have an individual surface area whose height or diameter corresponds at most to one-half the wavelength of the signal, and the emitter has a height or a diameter which is greater than one-half the wavelength of the signal.

Abstract: A method for estimating an underwater acoustic sound velocity in a network of acoustic nodes arranged along towed acoustic linear antennas and in which a plurality of acoustic signals are transmitted between the nodes. The method includes: obtaining two predetermined distances each separating a couple of nodes placed along a same first acoustic linear antenna (31); for each couple of first and second nodes, obtaining a first propagation duration of an acoustic signal transmitted between said first node and a third node placed along a second acoustic linear antenna and a second propagation duration of an acoustic signal transmitted between said second node and said third node; and estimating said underwater acoustic sound velocity, as a function of said two predetermined distances and said first and second propagation durations obtained for each couple of nodes.

Abstract: Embodiments contemplate methods and systems for determining an image performance measurement in an ultrasound system. Embodiments contemplate that data may be received from a remote unit of an ultrasound imaging system. One or more determinations of the measure of performance of an image may be made, where the image may be derivable from at least part of the data. The measure of image performance may be displayed on a main unit of the ultrasound imaging system.

Abstract: An acoustic positioning device includes an acoustic emitter and receiver. The device emits a sequence of at least one first acoustic signal (S1) and one second acoustic signal (S2), separated by a time interval T, and to receive and measure the arrival phase ?1 of S1 and the arrival phase ?2 of S2. The device measures a relative displacement between the acoustic emitter and the acoustic receiver and determines the approximate difference (R2?R1)AUX between the distance R1 traveled by S1 between the acoustic emitter and receiver, and the distance R2 traveled by S2 between the acoustic emitter and the acoustic receiver, and calculates the relative displacement (R2?R1) between the acoustic emitter and the acoustic receiver as a function of the approximate difference (R2?R1)AUX, of the time interval T and of the arrival phases ?1, ?2 respectively of S1 and of S2.

Abstract: A beamforming sensor node has an array of pressure wave sensors and beamforming circuitry. Each pressure wave sensor is configured within a unique processing channel including a time delay circuit for producing a signal, with a phase offset, representative of received pressure waves at said pressure wave sensor. The beamforming circuitry includes the time delay circuits for all processing channels and (a) sets the phase offset of each processing channel and (b) parallel processes all signals from the array of pressure wave sensors through respective time delay circuits to form a first coherent beam-formed signal from the node. A secondary beamforming node combines coherent beam-formed signals from the plurality of sensor nodes to produce a combined acoustic signal representative of received pressure waves at all sensor nodes.

Abstract: A method of combining at least two audio signals for generating an enhanced system output signal is described.

Abstract: The present invention allows the simple measurement of position and orientation with low cost setup and simple calibration using a small set of transmitting nodes and a simple handheld wand. This can be used in place of measuring tools such as non contact reflection based ultrasonic measurement tools or traditional tools such as tape measures and rulers where multiple high precision measurements are needed with minimal set up time. The present invention also provides true three dimensional output and orientation calculation.

Abstract: Systems and methods for parallel and distributed processing of audio signals produced by a microphone array are described. In one aspect, a distributed signal processing system includes an array of microphones and an array of processors. Each processor is connected to one of the microphones and is connected to at least two other processors, enabling communication between adjacent connected processors. The system also includes a computing device connected to each of the processors. Each microphone detects a sound and generates an audio signal, and each processor is configured to receive and process the audio signal sent from a connected microphone and audio signals sent from at least one of the adjacent processors to produce a data stream that is sent to the computing device.

Abstract: A method and apparatus for determining the direction of a sound source is disclosed. The method includes determining time differences of arrival of the sound at N locations and using the differences to determine the angular direction of the source. The apparatus indicates the angle of arrival and additionally indicates the type of the sound source.

Abstract: In one embodiment, an acoustic distance measurement system can use a modulation pattern to modulate a carrier wave. The modulated carrier wave may be transmitted to an acoustic transducer. An echo of the transmitted signal can be detected by correlating the received signal with the modulation pattern. Subsequent to detecting sufficient correlation between the received signal and modulation pattern, a distance determination can be made to determine the distance to the object that produced the received echo.

Abstract: A beamformer for an ultrasound system and a method for developing a beamformer are provided. The beamformer includes an RF interface configured to be connected to receiver boards that are connected to a probe. The method includes providing receiver boards, wherein each of the receiver boards is capable of conveying a common number of channels per board and has substantially similar circuit components and layouts. The method also includes selecting a number of channels per probe to be conveyed in parallel between a probe and the receiver boards, wherein the channels per probe is an integer multiple of the channels per board. The method further includes determining a combination of the receiver boards to use in the beamformer based on the number of channels per probe, wherein the receiver boards are capable of being used in at least first and second different combinations that support first and second different numbers of channels per probe.

Abstract: An object is detected without being constrained by the positional relationship between the object and the detecting position. A detection device includes a pseudo sound source and a monitoring unit. The pseudo sound source generates a scanning sound wave of a phase-conjugate wave in the time domain based on an acoustic signal by performing active phase conjugation, and causes the scanning sound wave to converge on the detection object from the above thereof within the propagation space by utilizing a feature that the scanning sound wave converges on the pseudo sound source which is the generation source of the acoustic signal. The monitoring unit extracts a reflected sound wave which is reflected at the detection object from the sound wave in the propagation space by performing passive phase conjugation. The detection object is detected based on presence or absence of the extracted reflected wave.

Abstract: Systems and methods for detection and analysis of amplitude modulation of underwater sound employ a product of a time delayed first electrical signal with a second electrical signal to generate a summed-product signal. The time delayed first electrical signal and the second electrical signal have an amplitude modulation indicative of characteristics of a vessel propeller. The summed-product signal is analyzed to detect a vessel and to determine the characteristics of the vessel propeller. In some arrangements a plurality of summed-product signals are analyzed to also determine a depth of the detected vessel.

Abstract: A transducer device for converting an analog DC voltage signal into a digital signal is provided, with an oscillator device for outputting a first oscillator signal and a second oscillator signal, whereby the oscillator device is formed to generate the first oscillator signal and the second oscillator signal phase-locked to one another and with the substantially same frequency from a reference signal, with an analog frequency converter connected to the oscillator device for transforming the analog DC voltage signal by the first oscillator signal in a first spectral range with a first center frequency to obtain a transformed signal, with an analog-to-digital converter for converting the transformed signal into a transformed digital signal; and with a digital frequency converter connected to the oscillator device for transforming the transformed digital signal by means of the second oscillator signal in a second spectral range with a second center frequency to obtain the digital signal.

Abstract: The invention relates to a solid-state range sensing system. As with previous solid-state range sensing systems, an energy source is activated and deactivated in a cyclic pattern with a selected source frequency. A receiver is adapted to sense the reflection of emitted energy from the target. The receiver includes a shielding system to block the sensing of the reflected energy from the target in a cyclic pattern with a selected receiver frequency. Unlike the prior art, the frequency of the source and receiver are offset by a small frequency. The resulting output signal of the receiver is a further cyclic pattern beat signal of frequency equal to the difference between the source activation and receiver shielding modulation frequencies. The best signal is effectively a down-converted version of the source modulation frequency and, unlike the prior art, is compared with a reference beat signal whereby the phase difference between the two beat signals is used to determine a range value.

Abstract: An apparatus and associated method are disclosed which form a multiple beam forming network using time division multiplexing. Instead of having several parallel sets of beam forming network hardware running at a given sampling clock rate, a simpler, single piece of hardware is run at a faster rate equal to the given sampling clock rate times the number of beams to be formed. Each sample received from each element is time division multiplexed into a bit stream, one for each beam. These time division multiplex element samples are weighted to apply the desired phase shift/time delay per element. Each weighted resultant is delayed in a cascade delay pipeline and then combined with the cascade combiner to form a beam at a given time division instant. This process is repeated for the next set of time division multiplexed samples and weights from each element of the array at a given time to form the next beam. The process is repeated for all beams until the sampling time interval ends.

Abstract: A MEMS directional sensor system capable of determining direction from a microphone to a sound source over a wide range of frequencies is disclosed. By utilizing a parallel filter bank that relies on a slow wave structure in a MEMS device, such as described herein, a very small microphone, on the order of a few micrometers, can be designed with unsurpassed ability to detect a sound source location.

Abstract: An acoustic position measurement system and method includes an acoustic transmitter operable to transmit a sound wave into an underground well bore in a target formation. The sound wave is configured to reflect from a boundary formation proximate the target formation. The system includes an acoustic receiver operable to receive a reflected sound wave. The reflected sound wave comprises a reflection of the sound wave from the boundary formation. The system also includes an electronics portion electrically coupled to the acoustic receiver. The electronics portion is operable to process the reflected sound wave and produce, based upon a characteristic of the reflected sound wave, data output indicative of a position of the acoustic position measurement system in the target formation.

Abstract: In accordance with the present invention, a system and method for computing a location of an acoustic source is disclosed. The method includes steps of processing a plurality of microphone signals in frequency space to search a plurality of candidate acoustic source locations for a maximum normalized signal energy. The method uses phase-delay look-up tables to efficiently determine phase delays for a given frequency bin number k based upon a candidate source location and a microphone location, thereby reducing system memory requirements. Furthermore, the method compares a maximum signal energy for each frequency bin number k with a threshold energy Et(k) to improve accuracy in locating the acoustic source.

Abstract: A system and method to provide maximum power over large angular sectors using an array of transducers is disclosed. Array segments of transducers and phase shifters form a beam from each of the array segments, wherein the set of beams overlap to form a large sector coverage beam. The phase of each of the signals fed to the radiating elements is shifted, such that the difference between beam point directions of the beams of two adjacent array segments is substantially equal to one half of the sum of the beamwidths of the beams of the two adjacent array segments. The phase of each of the signals fed to the radiating elements may also be shifted in proportion to the square of the distance between one end of the array of transducers and the position of each of the plurality of radiating elements.

Abstract: The invention relates to a system and method for processing a signal being emitted from a target signal source 20 into a noisy environment, wherein said target signal source 20 is located in a target signal source direction &phgr;s with regard to the position of a transducer array 10, the method comprising the following steps: receiving, transforming and filtering said signal according to filter coefficients of a beamformer 30I, 30II in order to generate at least one beamformer output signal y′i(n), i=1 . . . N, the filter coefficients defining a desired predetermined filter characteristic of the beamformer; and generating a control signal t(n) representing said target signal source direction &phgr;s. It is the object of the invention to improve such a system and method in the way that clear signal reception is achieved for any target signal source direction &phgr;s with only a minimum of computational effort and memory capacity.

Abstract: In accordance with the present invention, a system and method for computing a location of an acoustic source is disclosed. The method includes steps of processing a plurality of microphone signals in frequency space to search a plurality of candidate acoustic source locations for a maximum normalized signal energy. The method uses phase-delay look-up tables to efficiently determine phase delays for a given frequency bin number k based upon a candidate source location and a microphone location, thereby reducing system memory requirements. Furthermore, the method compares a maximum signal energy for each frequency bin number k with a threshold energy Et(k) to improve accuracy in locating the acoustic source.

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: A method and system for use in an air acoustic system for determining and using beamform factors for forming air acoustic beams approximating an optimum air acoustic beam for the directional transmission or reception of air acoustic energy by an air acoustic phased array system. Maximum and minimum dependent beamform factors of an optimum beam are determined from initial beamform factors and an initial parent population of chromosomes is generated, each chromosome including a gene corresponding to a dependent beamform factor and representing an initial candidate beam and subsequent parent populations are generated by cloning of the chromosomes of surviving populations. A child population is generated from a parent population by exchanging statistically selected pairs of genes of the parent population and generating a mutated population from the child population by mutating statistically selected genes of the child population.

Abstract: A vertical hydrophone cable includes a support cable, a plurality of hydrophones, and an equal number of delay elements which are tuned to provide synchronization between the seismic and electrical signals. A number of such vertical hydrophone cables are provided. In operation, the vertical array provides a method of seismic exploration comprising the steps of deploying the plurality of vertical hydrophone cables with the integral delay elements, generating a seismic signal, and receiving reflected return signals at the plurality of hydrophones with synchronism between the electrical and sound signals, so that the vertical cable functions in the manner of a traveling wave antenna.

Abstract: A method for determining the positions of the N array elements of a random rray to an accuracy sufficient to accomplish beam forming is provided where the initial positions of the array elements are known to an accuracy of .lambda..sub.min/2, and where .lambda..sub.min is the wavelength of the highest frequency of any of the M cohering sources which are in the field of the array and where the relative directions are unknown. The method includes the steps of: identifying M cohering sources in the field of the array, each of which emits at least one narrowband frequency, each frequency differing from the adjacent frequency by 1/T, where T is the time period of the measurements; a device for measuring the true bearing of one of the M sources; receiving the M cohering signals at the N array elements; performing a Fast Fourier Transform (FFT) on each of the N element signals; examining the spectrum of each of the N received signals; and from the N spectra, selecting M (M>3) lowest angular frequencies, .omega..

Abstract: An array transducer ultrasound beamformer includes a plurality of processing channels, one for each active element of the transducer array. Each channel includes a digitizing unit for converting the received signal to digital samples and a time multiplexed delay unit for producing a primary stream of delayed TDM samples corresponding to one or more beams. Within each channel, the primary stream of delayed TDM samples is demultiplexed in order to separate the stream in a plurality of secondary streams of delayed TDM samples, wherein each of the secondary streams corresponds to a portion of a beam or a single beam.

Abstract: A beamformer includes an array having a plurality of channels of delay elements which are constructed of charge coupled devices (CCDs). Each channel has a first plurality of delay elements cells which perform beam focussing and a second plurality of delay elements which perform beam steering. In this manner beam steering delays and beam focussing delays may be calculated independently. Typically, the second plurality of delay elements have a resolution which is typically coarser than the resolution of the first plurality of delay element cells which function to focus the beam. A signal may be inserted into any one of the delay elements of the first plurality to provide an appropriate delay. The signal is then output from the last delay element of the first plurality to the second plurality. The signal is delivered from a selected delay element of the second plurality to a charge sum data bus, which combines the signals output from each of the channels.

Abstract: A broadband sonar system in which a broadband output from a conventional narrowband sonar sensor array is used to capture broadband acoustical input signals. A single broadband beamformer receives the input from each of the sensors (such as hydrophones) of the array. The broadband output signal from each sensor of a particular subarray is coupled to a corresponding one of a plurality of first filters. Each first filter emphasizes those frequencies of each subarray which have the least noise. In addition, the output is attenuated for frequencies below the design frequency, with lower frequencies being attenuated to a greater degree than higher frequencies. A plurality of second and third filters, each corresponding to a subarray, are provided to compensate for the effects of the frequency and sensor spacing on the signal as the beam rotates.

Abstract: A sound enhancement system including a beamed linear array microphone system for the acoustic pickup of voice and music from substantial distances with a relatively narrow sound pickup beam and with the avoidance of acoustic feedback. The acceptance beam angle is relatively constant over the desired sound octaves. Response outside of the acceptance beam is relatively low. The system includes a microprocessor-controlled circuit for processing the signals from a multiplicity of microphone elements in the linear array for application to a loudspeaker.

Abstract: A range-finding system for measuring a target distance from a point of measurement to a target object, comprising a slave unit for calculating and indicating the target distance based on a waiting time from transmission of an interrogation signal to reception of a response signal and a master unit placed at a certain correction distance from the target object for transmitting the response signal when a delay time corresponding to the correction distance has elapsed from reception of the interrogation signal.

Abstract: Charge coupled shift registers for sonar beamforming provide many channels of high resolution large delays by the cascading of two registers. Two equivalent embodiments are disclosed. In one embodiment the shift rate of the input shift register is an integer multiple "m" of the shift rate of the output shift register which is responsive to every m th signal presented to it. The other embodiment samples the signal in the input register by selected m th pulses of a pulse train whose frequency is m times the shift frequency of the output register. Each embodiment preserves the higher resolution phase information and incremental delay of the higher frequency sampling of the input shift register. The long time delay is provided by the output shift register operating at the lower shift rate.

Abstract: Provided is a sound source determining system which can accurately and economically identify the position of aircraft in an airport or the like. The direction of a sound source is determined by arranging a plurality of acoustic sensors (S0, S1, S2, S3, . . . , S-1, S-2, S-3, . . . ) in an array at a prescribed interval for detecting an acoustic signal produced from the sound source, connecting a plurality of delay circuits (D0, D1, D2, D3, . . . , D-1, D-2, D-3, . . . ) having delay times which are different from one to a next by a unit time period (.tau.) to the outputs of the acoustic sensors, adding up the outputs of the delay circuits in an adder circuit (AD), and determining the direction of the sound source according to the unit time period (.tau.) which will maximize the output of the adder circuit.

Abstract: A delay interpolator for use in each channel of a digital ultrasound beamformer includes an FIR digital filter that is responsive to delay control information for delaying digital samples of the received beam by different delays that are quantized in increments less than the sampling period and a control unit for supplying the delay control information to the FIR digital filter. In a preferred embodiment, all but one of the filter coefficients are of the form 1/2.sup.m, where m is an integer, and multiplication is implemented in the FIR digital filter by shifting bits of the data samples by m bit positions. The FIR digital filter preferably includes a gain correction multiplier for correcting the gain of the delayed digital samples. The FIR digital filter delay interpolator can utilize a pipeline structure for high speed operation. In addition, the FIR digital filter delay interpolator can be used in a time multiplexed beamformer to process several beams simultaneously.

Abstract: An array of transducer elements receives energy from a target or targets in a field of view and operates on the transducer outputs to provide a plurality of different levels of shading. The most useful portion of the field pattern is selected and combined with other most useful portions of other field patterns into a single composite display which results in one or more relatively narrow lobes, indicating targets, and without the presentation of side lobes which may be masking targets.

Abstract: A 3-D sonar image display takes two sonar signals from the same event, slightly displaced from one another in time, space, or both. Each signal is converted from audio to video, and is presented to a separate eye of the sonar operator. The coherent parts of the signal--those actually produced by the event--will be fused by the optical portions of the brain into a three-dimensional image. The noise portions of the signal will not be coherent, and will not produce a three-dimensional image.

Abstract: In a method of formation of channels for a sonar, after having sampled at a frequency T=1/4f.sub.0 (where f.sub.0 is the receiving center frequency of the sonar) the signals from the hydrophones of the sonar and having translated them to baseband, the signals thus translated are subsampled with a period T.sub.SE =kT (wherein k is an integer) substantially equal to 1.25 B, where B is the reception bandwidth of the sonar. A first set of signals is subsampled at identical times to form a frontal sector. Two further sets of signals are subsampled with delays between the signals from two adjacent hydrophones equal to T, which determines two side sectors adjacent to the frontal sector. The subsampled signals are then transmitted serially by the towing cable of the sonar device towed array and are processed in FFT circuits which allow to form in each sector a set of channels covering the sector.

Abstract: An acoustin transducer system for a borehole televiewing apparatus is set forth. In the preferred embodiment, a ceramic circular disc is used and is divided by grooves selected thereon into a set of N concentric rings where N is a whole number integer. Each ring has its own associated transmitter and they are fired in a controlled sequence. Each ring operates as a receiver, and they form output signals which are amplified and controlled delay at the respective delay lines, the several output signals are summed. This assures that the illuminated regions of the borehole is in focus and has a greater depth of field. And a method is also described whereby multiple simultaneous electronically formed acoustic beams are utilized in a differential mode to achieve high spatial resolution in time of flight measurements.

Abstract: A passive acoustic detector including a line hydrophone and apparatus coud thereto operable to utilize the energy sensed by the elements of the hydrophone during passive listening to effect scanning in depression-elevation by delaying for directivity and then combining acoustic energies sensed by the hydrophone elements and recording the combined energies on an x-y strip recorder for enhanced signal-to-noise ratio.

Abstract: Apparatus and method for sonar or radar target tracking. Digital apparatus nd techniques are employed. A variable delay is used for beam steering.

Abstract: Quantized delay values used in a digital beamformer are selected so as to minimize the derivative of the beamformer pattern. A first set of quantization error values, one for each hydrophone, is determined from the precise delay values and a second set determined by adding a shading factor times the sample period to each member of the first set. Each set of combinations of members of the first and second sets of error values is then examined to determine which set minimizes the derivative of the beamformer pattern. The quantized delay values are then determined by selecting the quantized delay value corresponding to the error value in the set which minimizes the derivative.

Abstract: A planar end-fire acoustic transducer array is composed of a planar matrix f individual elements. In order to give this array an end-fire characteristic, predetermined elements are provided with outputs which are phase-inverted with respect to the outputs of the other elements of the array, the sum of the gains of these predetermined elements being made equal to the sum of the gains of the other elements.

Abstract: A system for acquiring an ultrasound signal comprises a signal processing unit adapted for acquiring a received ultrasound signal from an ultrasound transducer having a plurality of elements. The system is adapted to receive ultrasound signals having a frequency of at least 20 megahertz (MHz) with a transducer having a field of view of at least 5.0 millimeters (mm) at a frame rate of at least 20 frames per second (fps). The signal processing can further produce an ultrasound image from the acquired ultrasound signal. The transducer can be a linear array transducer, a phased array transducer, a two-dimensional (2-D) array transducer, or a curved array transducer.