Abstract: Frequency-steered acoustic arrays transmitting and/or receiving multiple, angularly dispersed acoustic beams are used to generate 2D and 3D images. Input pulses to the arrays are generally non-linear, frequency-modulated pulses. Frequency-steered acoustic arrays may be provided in one-dimensional linear and two dimensional planar and curvilinear configurations, may be operated as single order or multiple order arrays, may employ periodic or non-periodic transducer element spacing, and may be mechanically scanned to generate 2D and 3D volumetric data. Multiple imaging fields of view may generated in different directions by switching the polarity of phase-shifted array transducer elements. Multiple frequency-steered arrays arranged in an X-configuration provide a wide, contiguous field of view and multiple frequency steered arrays arranged in a T-configuration provide orthogonally oriented fields of view.

Abstract: Frontal sonar for observing the seafloor, characterized in that it includes: elements for insonifying a seafloor area divided into M sectors, able to perform a characteristic insonification of each sector of the area during an operation recurrence of the sonar; and receiving elements including a physical antenna consisting of an array of K transducers, the antenna being lacunar and thus ambiguous, so that it defines N image lobes, and in that each of the characteristically insonified sector is associated with a single image lobe defined by the antenna, so that the antenna ambiguity is removed.

Abstract: In an ultrasound receive beamformer signals from two or more aperture elements are multiplexed at the input of each beamformer channel, stored in different portions of a delay memory, delayed and apodized in a time-multiplexed fashion, demultiplexed at the output of the channel, and summed in different summation units running at an upsampled rate. The partial sums are then time-aligned, summed to produce the total upsampled beam sum, filtered and decimated in an interpolation filter to produce the beamformed signal.

Abstract: Analog beamformers for continuous wave ultrasonic receivers, typically realized in integrated circuit form and using a direct quadrature baseband conversion architecture for CW Doppler to eliminate a second down conversion mixer and second synthesizer. The beamformers use integrated mixers and LO's for phase steering, and dedicated ring counters for each channel for lower noise. Input filtering may be provided with switchable RF input low pass filters. The integrated circuit includes the ultrasound signal VGA and beamformer on the same chip. An auxiliary channel may be included for a self-test mode. Also a programmable bit soft shutdown feature, programmable via the serial port, allows disabling individual channels. Various other features are disclosed including cascading of multiple integrated circuits for a much greater number of channels.

Abstract: An ultrasonic diagnostic imaging system has a two dimensional array arranged in multiple patches of multiple transducer elements. Each patch of transducer elements is coupled to a group of microbeamformer delay lines having outputs coupled to a channel of a system beamformer, which beamforms the partially summed beams of each patch into a final beamformed signal. The outputs from multiple patches which are not simultaneously used in the active receive aperture are coupled to a common beamformer channel, enabling the number of patches of the array to exceed the number of channels of the system beamformer without the use of multiplexers.

Abstract: In an under water detection for detecting the phase difference of an echo by two reception beams according to a split beam method, the difference ?? between the phase difference of an echo detected by first and second reception beams formed in some direction and the phase difference of the echo detected by first and second reception beams which is formed in a direction rotated from the former direction concerned by a predetermined angle is detected by a phase detector. A reliability judging unit judges whether the difference ?? detected by the phase detector is within a predetermined range or not. If the difference ?? is within the predetermined range, an echo is displayed on a display unit. If the difference ?? is not within the predetermined range, the echo is displayed with a specific color tone or the echo is not displayed.

Abstract: The present invention relates to a sonar method and apparatus of tracking objects underwater. Specifically, the method and apparatus can be used to acoustically track a multitude of objects in a hemispherical volume 360° azimuth and 180° elevation relative to the location of the apparatus. The method and apparatus of the present invention provide four-dimensional, real-time tracking of underwater objects.

Abstract: The present invention relates to a digital beamformer in ultrasound imaging after the process of receiving a digital echo signal. Provided herein is a time multiplexed device and method for beamforming. The device includes an echo data write/read unit, a multi-beam processing unit, a channel data summing unit, and a parameter distributing and synchronizing unit for distributing and synchronizing respective receive parameters to the echo data write/read unit and the multi-beam processing unit through a parameter load bus for each of the beams in the channel.

Abstract: Frequency-steered acoustic arrays transmitting and/or receiving multiple, angularly dispersed acoustic beams are used to generate 2D and 3D images. Input pulses to the arrays are generally non-linear, frequency-modulated pulses. Frequency-steered acoustic arrays may be provided in one-dimensional linear and two dimensional planar and curvilinear configurations, may be operated as single order or multiple order arrays, may employ periodic or non-periodic transducer element spacing, and may be mechanically scanned to generate 2D and 3D volumetric data. Multiple imaging fields of view may generated in different directions by switching the polarity of phase-shifted array transducer elements. Multiple frequency-steered arrays arranged in an X-configuration provide a wide, contiguous field of view and multiple frequency steered arrays arranged in a T-configuration provide orthogonally oriented fields of view.

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: The invention concerns the resolution of directional information in sonar arrays. In particular it concerns a method for resolving such directional information, which may be useful in hydrographic surveys. The method comprises the steps of receiving a block of sensor data, containing time series from an array of hydrophone sensors, and beamforming to produce beam data including estimates of the directions of arrival from those beams and estimates of source strength. The method further comprises the steps of selecting a subset of the beams and refining the estimates of the directions of arrival from those beams, and, combining the refined estimates of directions of arrival from those beams with either the sensor data or the beam data, and performing a fit to the sensor data or beam data to develop an output containing refined direction of arrival data and refined source strength data.

Abstract: System for evaluating the traffic environment of a motor vehicle and for influencing the speed of the motor vehicle in its own traffic lane, comprising an electronic control unit, which is connected to a signal transmitter that produces a signal characteristic of the desired speed of the motor vehicle, a signal transmitter that produces a signal characteristic of the yaw of the motor vehicle about its vertical axis, a signal transmitter that produces a signal, which is characteristic of the articles situated, in the direction of travel of the motor vehicle, in front of the motor vehicle in terms of their spacing and orientation relative to the motor vehicle and which is the speed relative to the speed of the system motor vehicle and/or the spacing relative to the system motor vehicle and/or the angular offset or the cross track distance relative to the vehicle longitudinal axis of the system motor vehicle, and a signal transmitter that produces a signal characteristic of the speed of at least one wheel of the

Abstract: The present information comprises the stages of: applying frequency analysis to positional information on a platform, generating virtual positional information on the platform based on a frequency analysis result; extracting a signal based on the generated virtual positional information; and performing a synthetic aperture processing based on the extracted signal, and in this manner, even if the positional information lacking in precision and inaccurate is used, the shake compensation of the platform in the synthetic aperture processing system can be effectively performed.

Abstract: A target tracking arrangement predicts the state of a target. The predictor may be a Kalman filter. In the presence of a target which is maneuvering, the prediction may be in error. A maneuver detector is coupled to receive residuals representing the difference between the predictions and the target state. The maneuver detector is matched to the predictor or Kalman filter to thereby tend to reduce the undesirable effects of system noise. The matching may be of the frequency response.

Abstract: A processing technique to apply high resolution, non-Fourier based beamformers to practical active sonar system implementations.

Abstract: The apparatus includes transmitter-receiver units (10, 20) for emitting acoustic signals in the form of beams (F1, F2) directed rearwardly of the stern and for receiving acoustic signals reflected by the fixed structure (B, C). The number of transmitter-receivers and the beam angles of the respective beams are determined so as to include substantially the entire area behind the stern in their field of view. Each transmitter-receiver includes a transducer for converting input electrical signals into output acoustic signals and for converting reflected acoustic signals into output electrical signals which are supplied to an electronic processor unit. On the basis of electrical input and output signals, the processor unit determines the instantaneous distance between the vessel and the fixed structure. A visual and/or acoustic signalling device is connected to the processor unit for emitting a visual and/or acoustic signal in real time indicating the instantaneous distance determined.

Abstract: A method and system for synthetic aperture sonar provide improved position estimates of a receive array as in moves through a body of water.

Abstract: A processing technique and transducer field of view architecture for use as part of an imaging sonar system to develop three-dimensional images of the space below, to the sides, and forward of a ship.

Abstract: This invention exploits the synchronization properties of coupled, nonlinear oscillators arrays to perform power combining, beam steering, and beam shaping. This architecture utilizes interactions between nonlinear active elements to generate beam patterns. A nonlinear array integrates the signal processing concurrently with the transduction of the signal. This architecture differs fundamentally from passive transducer arrays in three ways: 1) the unit cells are nonlinear, 2) the array purposely couples the unit cells together, and 3) the signal processing (beam steering and shaping) is done via dynamic interactions between unit cells. The architecture extends to both 1- and 2-dimensional arrays.

Abstract: A method and system for synthetic aperture sonar provide improved position estimates of a receive array as in moves through a body of water.

Abstract: A parallel GSC structure is provided by which an adaptive process is performed by a plurality of beamformers in parallel in such a way that they present a common response to the equalization signal that varies over time in an optimal manner with respect to the statistics of the steering vectors.

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: A sensor for detecting acoustic energy includes a microstructure tuned to a predetermined acoustic frequency and a device for detecting movement of the microstructure. A display device is operatively linked to the movement detecting device. When acoustic energy strikes the acoustic sensor, acoustic energy having a predetermined frequency moves the microstructure, where the movement is detected by the movement detecting device.

Abstract: An automatically tracking scanning sonar alternately performs horizontal scanning and vertical scanning and a target lock processor calculates a predicted position of a target based on an echo signal previously received from the target when the echo signal from the target is interrupted. A selector sets a range, tilt angle and sounding direction and outputs them to a transmit-receive controller such that the scanning sonar can scan the predicted target position. As the depth of the target is determined by performing the vertical scanning, the tilt angle of an umbrellalike beam pattern produced by the horizontal scanning can be varied to follow the target by controlling the tilt angle based on target depth information even when the target moves in vertical directions. It is therefore possible to automatically track the target in a reliable fashion.

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: A data-based technique is disclosed that defines the amplitude and phase of acoustic signals for detection as they propagate across an array of sensor elements for each array incident angle of interest. The definitions of the acoustic signals are then used to constrain adaptive noise suppression operating routines from canceling desired acoustic representative of desired incident direction detector. The data-based technique of defining acoustic signals also leads to a greater reduction of noise in directions where signal is not present. The use of this technique within an adaptive-array-beamforming-processor, and more particularly in connection with the provision of data-based steering vectors therefor, results in an improvement in the ability to detect acoustic signals imbedded in noise.

Abstract: A receiving beam is formed using 60 elements arranged in a 90° sector area of a cylindrical receiving array. Receiving beam 0 is formed with elements 0-59 divided into two (front and rear) groups. Specifically, the elements 0-59 are divided into rear group 1 (elements 0-8, 51-59) and front group 2 (elements 9-50) in the beam direction, and the receiving beam is formed by using sample data obtained from the transducer elements 0-8, 51-59 of group 1 in a current scanning cycle as well as sample data obtained from the transducer elements 9-50 of group 2 in a preceding scanning cycle. This approach makes it possible to form the receiving beam such that incoming waves of a short-pulse signal would simultaneously hit the relevant transducer elements of the receiving array and thereby improve directivity and sensitivity of the receiving beam for the reception of short-pulse waves.

Abstract: A received beam-forming apparatus is disclosed is which echo signals received by multiple ultrasonic transducer elements arranged in a linear form are sampled at a specific scanning frequency to obtain sample data. A receiving beam-forming apparatus includes a memory which stores the sample data derived from multiple scanning cycles; and a beamformer which divides the multiple ultrasonic transducer elements into multiple blocks, reads out the sample data derived from different scanning cycles for the individual blocks from said memory, and forms a receiving beam in a specific direction using the individual sample data which have been read out. A sonar system using the receiving-beam forming apparatus is also disclosed as is a matched filter which selects an arc-shaped part of an ultrasonic transducer element array.

Abstract: A method and system for processing received sonar signals. The method and system generate bearing data signals based on the received sonar signal. The method and system continuously determine the signal strength of the received sonar signal and also continuously determine the total noise from the received sonar signal in the ocean environment in which the target is located. The method and system provide a sensor gain in response to the determined total noise and the signal strength, and adaptively calculate filter coefficients from the sensor gain and the determined total noise. The method and system also filter the generated bearing data signals using a filter having the calculated filter coefficients.

Abstract: An ultrasonic transmitter generates a reference signal based on a clock signal of a specific frequency and a control signal made up of binary values 0 and 1 for controlling how the level (High or Low) of a carrier drive signal should change, and generates an analog signal constituting the carrier drive signal by pulse-duration-modulating the reference signal. Produced from the carrier drive signal, a driving pulse signal is shaped into a curved waveform having a gradually rising leading edge and a gradually falling trailing edge as the amplitude of the carrier drive signal is gradually increased and decreased based on the control signal.

Abstract: The invention provides an ultrasonic transmit-receive apparatus which solves a false image problem caused by grating lobes and side lobes and offers high bearing resolution without increasing in the scale of hardware or in manufacturing cost. Using a transducer having multiple transducer elements arranged on a surface of the transducer along its circumferential direction, the apparatus emits ultrasonic waves in directionally varying frequency bands and receives echo signals from specified angular directions while selecting the frequency from one direction to another.

Abstract: The present invention relates to a multiple beamforming processor formed with an integrated circuit in which a plurality of beams can be formed simultaneously.

Abstract: A receiving beam is formed using 60 elements arranged in a 90° sector area of a cylindrical receiving array. Receiving beam 0 is formed with elements 0-59 divided into two (front and rear) groups. Specifically, the elements 0-59 are divided into rear group 1 (elements 0-8, 51-59) and front group 2 (elements 9-50) in the beam direction, and the receiving beam is formed by using sample data obtained from the transducer elements 0-8, 51-59 of group 1 in a current scanning cycle as well as sample data obtained from the transducer elements 9-50 of group 2 in a preceding scanning cycle. This approach makes it possible to form the receiving beam such that incoming waves of a short-pulse signal would simultaneously hit the relevant transducer elements of the receiving array and thereby improve directivity and sensitivity of the receiving beam for the reception of short-pulse waves.

Abstract: A digital multiline beamformer is provided which produces multiple receive beams in response to a single transmit event. An embodiment of the present invention includes a bulk delay which provides a common steering delay applicable to all of the beams received at one time. The bulk delay is succeeded by parallel filter processing paths which produce finely focused multiple beams simultaneously. In one embodiment a multiphase filter produces the samples for multiple beams, which is advantageous when the number of simultaneously produced beams is greater than the number of phases produced by the fine focus filter.

Abstract: A sonar array for forming multiple transmit and/or receive acoustic beams by a frequency beamforming technique. In frequency division beamforming, beam steering direction is made a function of frequency by driving (receiving) each element of a uniformly spaced line array by a signal which leads or lags its nearest neighbor by a fixed phase shift, &Dgr;&phgr;. This permits scanning a transmit and/or receive beam through a range of angles by changing its frequency. The same principle can be used to form multiple simultaneous transmit and/or receive beams. This is accomplished by transmitting a wide bandwidth signal and receiving the echoes through a spectrum analyzer. Each frequency bin of the spectrum analyzer then corresponds to a beam pointing in its own unique direction. Advantages of such a sonar system include improved cost, weight, and size versus performance for a variety of systems including ahead looking sonars and bottom mapping sonars.

Abstract: A myocardial revascularization device has a catheter suitable for use in a myocardial revascularization procedure, the catheter including an elongate body having a proximal end and a distal end, and tissue-ablating means housed at least partially within the catheter and capable of effectuating tissue ablation adjacent the distal end of the catheter. The device further has an optical reflectance fiber housed within the catheter and coupled to an optical reflectance system. The device is operative to transmit a reflectance signal in the optical reflectance fiber, the reflectance signal including either short optical pulses or low-coherence light. The optical reflectance system is operative to gauge tissue ablation, measure a thickness of tissue adjacent the catheter, and/or determine a position of the distal end relative to adjacent tissue using either of optical time-domain reflectance or optical coherence interferometry.

Abstract: A sensor for detecting acoustic energy includes a microstructure tuned to a predetermined acoustic frequency and a device for detecting movement of the microstructure. A display device is operatively linked to the movement detecting device. When acoustic energy strikes the acoustic sensor, acoustic energy having a predetermined frequency moves the microstructure, where the movement is detected by the movement detecting device.

Abstract: A sonar array for forming multiple transmit and/or receive acoustic beams by a frequency beamforming technique. In frequency division beamforming, beam steering direction is made a function of frequency by driving (receiving) each element of a uniformly spaced line array by a signal which leads or lags its nearest neighbor by a fixed phase shift, &Dgr;&phgr;. This permits scanning a transmit and/or receive beam through a range of angles by changing its frequency. The same principle can be used to form multiple simultaneous transmit and/or receive beams. This is accomplished by transmitting a wide bandwidth signal and receiving the echoes through a spectrum analyzer. Each frequency bin of the spectrum analyzer then corresponds to a beam pointing in its own unique direction. Advantages of such a sonar system include improved cost, weight, and size versus performance for a variety of systems including ahead looking sonars and bottom mapping sonars.

Abstract: A method for estimating the curvature in a road is disclosed. The method measures an azimuth angle range and relative velocity between a host and a target vehicle, which determines whether a host vehicle is changing lanes or whether a target vehicle is changing lanes. The method calculates a heading angle of the host vehicle and calculates a corrected azimuth angle by adjusting the measured azimuth angle by the value of calculated heading angle. This method selects a curve that minimizes the mean square error between the curve and selected targets; and determines an equation that describes the curve, wherein the equation is used to predict the path head of the host vehicle.

Abstract: An automatically tracking scanning sonar alternately performs horizontal scanning and vertical scanning and a target lock processor calculates a predicted position of a target based on an echo signal previously received from the target when the echo signal from the target is interrupted. A selector sets a range, tilt angle and sounding direction and outputs them to a transmit-receive controller such that the scanning sonar can scan the predicted target position. As the depth of the target is determined by performing the vertical scanning, the tilt angle of an umbrellalike beam pattern produced by the horizontal scanning can be varied to follow the target by controlling the tilt angle based on target depth information even when the target moves in vertical directions. It is therefore possible to automatically track the target in a reliable fashion.

Abstract: An annular ultrasound bulk wave transducer array for electronic depth steering of symmetric focus from a near focus Fn to a far focus Ff includes elements that are divided into k groups with different fixed prefocusing. The central group participates in beam forming from Fn to Ff, the next outer group in beam forming from Fn1>Fn to Ff, and the kth outer group in beam forming from Fnk>Fn,k−1 to Ff. The fixed focus for the kth group is selected at Fk between Fnk and Ff. In this manner, beam formation close to Fn is performed only by the central group. By steering the focus outward from Fn, the focal diameter increases and, at a depth where the focal diameter exceeds a limit, the next outer group of elements is included in beam formation. This increase in aperture area reduces the focal diameter with subsequent increases in diameter as the focus is further steered toward Ff.

Abstract: A system and process for localizing signals received on multiple co-linear arrays reduces the adverse effects on localization performance due to background noise. The system and process coherently combine all possible array cross-correlograms. The resulting correlogram is a function of two variables, one which corresponds to a fine bearing estimate and a second with maps into range.

Abstract: A vehicle occupant sensor which utilizes an acoustic system for determining object range, extent, and direction. The system is composed of an ultrasonic transmitter formed from an array of air chamber resonator elements driven in relative phase to each other to produce a steered acoustic beam. Electrical excitation circuitry converts waveform data stored in memory elements to electrical signals to drive the transmitter. One or more ultrasonic receivers receives the acoustic waves reflected from objects, and a processor determines the range, extent and direction of the objects based on the received acoustic waves.

Abstract: A vehicle occupant sensor which utilizes an acoustic system for determining object range, extent, and direction. The system is composed of an ultrasonic transmitter formed from an array of air chamber resonator elements driven in relative phase to each other to produce a steered acoustic beam. Electrical excitation circuitry converts waveform data stored in memory elements to electrical signals to drive the transmitter. One or more ultrasonic receivers receives the acoustic waves reflected from objects, and a processor determines the range, extent and direction of the objects based on the received acoustic waves.

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 wideband-to-narrowband conversion method and apparatus performs the operational step of receiving an acoustic wideband signal, initially incident on an array of acoustic wideband transducers and subsequently digitized, and in response thereto generating a spatial Wigner bilinear kernel output signal, and the operational step of receiving and spatially bandpass filtering the spatial Wigner bilinear kernel output signal to remove a wideband low frequency portion as well as any unwanted noise therefrom and retain and output only a narrowband portion thereof.

Abstract: Sonar method and system for determining and using beamform factors for forming sonar beams approximating an optimum sonar beam for the directional transmission or reception of sonar energy by a sonar phased array system. Optimum maximum and minimum dependent beamform factors 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. Subsequent parent populations are generated by chromosome cloning. A child population is generated from a parent population by exchanging statistically selected pairs of genes and generating a mutated population. A surviving population is selected from the mutated population by a chromosomes comparison. When the surviving population chromosomes meet the criteria, the best match genes of the surviving population are selected for forming a beam.

Abstract: A submarine bow dome acoustic sensor assembly comprises an outer hull bow portion, an inner pressure hull wall extending athwartships and in conjunction with the outer hull bow portion defining a free-flood compartment, and an acoustic bow panel disposed in the compartment and connected to the pressure hull wall by acoustically isolating supports. A laser scanner is disposed in the compartment and is oriented so as to project a laser beam onto a surface of the acoustic bow panel, and a sensor is disposed in the compartment and oriented so as to receive reflections of the laser beam off the acoustic panel and to transmit data from which a position of a sound generating source can be determined.

Abstract: An electronic scanning ultrasonic object-detection apparatus 1 of the present invention comprises: phase control signal generation means 2 for generating phase control signals having the same transmission frequency; ultrasonic wave transmission means 3 for transmitting ultrasonic waves based on the phase control signals, by a plurality of arrays having a plurality of transmission elements arranged at a constant element interval, with the element interval being different for each array; ultrasonic wave receiving means 4 for receiving reflected waves from an object of the ultrasonic waves, and judging a signal Included in all the reflected waves as a main image to thereby output a main image signal, and judging other signals as side images to thereby output a side image signal; and object-detection means 5 for detecting a position of an object based on the main image signal and detecting existence of a side image based on the side image signal.

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.