Abstract: Sound and image are sampled simultaneously using a sound/image sampling unit incorporating a plurality of microphones and a camera. Sound pressure waveform data and image data are stored in a storage means. Then the sound pressure waveform data are extracted from the storage means, and a graph of a time-series waveform of the sound pressure level is displayed on a display screen. A time point at which to carry out a calculation to estimate sound direction is designated on the graph, and then sound direction is estimated by calculating the phase differences between the sound pressure signals of the sound sampled by the microphones, using the sound pressure waveform data for a calculation time length having the time point at the center thereof. A sound source position estimation image having a graphic indicating an estimated sound direction is created and displayed by combining the estimated sound direction and the image data sampled at the time point.

Abstract: A signal processing apparatus includes: a learning processing unit that finds a separating matrix for separating mixed signals in which outputs from a plurality of sound sources are mixed, by a learning process that applies ICA (Independent Component Analysis) to observed signals including the mixed signals; a separation processing unit that applies the separating matrix to the observed signals to separate the mixed signals and generate separated signals corresponding to each of the sound sources; and a sound source direction estimating unit that computes a sound source direction of each of the generated separated signals.

Abstract: A system for controlling signals coming from or going to an aircraft simulator has a first slave circuit and a second slave circuit. The second slave circuit is used to monitor signals coming from the aircraft simulator. A multiplexer circuit is coupled to the first slave circuit. The first slave circuit sends control signals to the multiplexer circuit for controlling digital output signals being sent to the aircraft simulator. A master controller is coupled to the first slave circuit and the second slave circuit. The master controller is used for controlling operation of the first and second slave circuit. A computer system is coupled to the master controller. The computer system will display a listing of the aircraft simulator signals to be controlled. Selection of a desired aircraft simulator signal by an input device of the computer system will allow one to control the selected aircraft simulator signal.

Abstract: A method for short range alignment using ultrasonic sensing is provided. The method includes shaping an ultrasonic pulse on a first device to produce a pulse shaped signal and transmitting the pulse shaped signal from the first device to a second device, receiving the pulse shaped signal and determining an arrival time of the pulse shaped, identifying a relative phase of the pulse shaped signal with respect to a previously received pulse shaped signal, identifying a pointing location of the first device from the arrival time and the relative phase, determining positional information of the pointing location of the first device, and reporting an alignment of three or more points in three-dimensional space. Other embodiments are disclosed.

Abstract: An apparatus and method of voice activity detection (VAD) are disclosed. To detect a target sound, a target sound detecting apparatus calculates the phase difference corresponding to each frequency component from a plurality of sound signals converted in frequency domain, calculates a characteristic value indicating possibility that the phase difference of the frequency component is within an allowable phase difference range of target sound calculated based on a direction angle of the target sound, and detects the presence and/or absence of target sound using the characteristic value.

Abstract: A method of locating a sound source based on sound received at an array of microphones comprises the steps of determining a correlation function of signals provided by microphones of the array and establishing a direction in which the sound source is located based on at least one eigenvector of a matrix having matrix elements which are determined based on the correlation function. The correlation function has first and second frequency components associated with a first and second frequency band, respectively. The first frequency component is determined based on signals from microphones having a first distance, and the second frequency component is determined based on signals from microphones having a second distance different from the first distance.

Abstract: An apparatus for detecting a cavity comprising a signal receiver, a signal analyzer and a threshold excedent determination processor. The signal receiver receives a reflected signal resulting from an interaction of multi-frequency irradiating signal(s) with at least one cavity. The irradiating signal may include an electromagnetic or acoustic signal above a cavity dependent cutoff frequency with a randomized spectral component. The signal analyzer computes cavity detecting statistic(s) of the reflected signal. The cavity detecting statistic(s) may include an autocorrelation function. The autocorrelation function may be a Fourier transform of the power spectral density of the reflected signal. The threshold excedent determination processor generates a notification when cavity detecting statistic(s) exceed a threshold. The threshold may include a multi-variable function. The cavity may be the bore of a weapon. The apparatus may be configured to determine the bearing from the cavity to the apparatus.

Abstract: A sound direction estimation apparatus includes a sound source model storage unit that stores likelihood of a sound source class in correspondence with a sound feature quantity, a sound signal input unit that receives a sound signal, a sound source identification unit that identifies a sound source class of the sound signal input from the sound signal input unit with reference to the sound source model storage unit based on the sound feature quantity of the sound signal, and a first sound source localization unit that estimates a sound direction of the sound signal of the sound source class identified by the sound source identification unit.

Abstract: The invention as disclosed is of a method to authenticate identify and trace sonar transmissions and echoes by embedding transparent, secure and robust digital watermarks in signal space, where the additional information incurs no cost in bandwidth. The complex short time Fourier transform is selected as the domain for embedding the digital watermark, secured by a secret key, in the time frequency representation of the signal. The watermark is designed through an iterative optimization step. This step insures that the watermarked sonar is also realizable. Selection of the time frequency region for watermarking is driven by avoidance of interference with the sonar itself, or in case of network operation, other watermarks. In addition, the selected time-frequency region remains robust to sound channel and other transmission effects. Sonar echoes are authenticated in the time-frequency plane by a correlation receiver tuned to the watermarked region using the secret key.

Abstract: The invention relates to a method for localizing and tracking acoustic sources (101) in a multi-source environment, comprising the steps of recording audio-signals (103) of at least one acoustic source (101) with at least two recording means (104, 105), creating a two- or multi-channel recording signal, partitioning said recording signal into frames of predefined length (N), calculating for each frame a cross-correlation function as a function of discrete time-lag values (?) for channel pairs (106, 107) of the recording signal, evaluating the cross-correlation function by calculating a sampling function depending on a pitch parameter (f0) and at least one spatial parameter (?0), the sampling function assigning a value to every point of a multidimensional space being spanned by the pitch-parameter and the spatial parameters, and identifying peaks in said multidimensional space with respective acoustic sources in the multi-source environment.

Abstract: A method for short range alignment using ultrasonic sensing is provided. The method includes shaping an ultrasonic pulse on a first device to produce a pulse shaped signal and transmitting the pulse shaped signal from the first device to a second device, receiving the pulse shaped signal and determining an arrival time of the pulse shaped, identifying a relative phase of the pulse shaped signal with respect to a previously received pulse shaped signal, identifying a pointing location of the first device from the arrival time and the relative phase, determining positional information of the pointing location of the first device, and reporting an alignment of three or more points in three-dimensional space. Other embodiments are disclosed.

Abstract: The invention relates to a method for determining the location of an impact on a surface of an object based on the analysis of an acoustic signal generated by the impact. This method further comprises a signal treatment step of weighting the acoustic signal to take into account spurious contributions in particular due to reflections at the border of the object.

Abstract: To enable precise calculation of a propagation time of a direct wave which arrives fastest from an ultrasonic generation source without being affected by a reflected wave of an ultrasonic signal. A plurality of ultrasonic signals generated based on a plurality of M sequences different from each other are propagated from a transmission side to a reception side, whereby the reception side generates model waveforms of the plurality of M sequences, executes correlation processing between each model waveform and a waveform of each ultrasonic signal and detects a secondary peak of a correlation value which appears when both waveforms partly coincide with each other to determine an M sequence which generates a smallest secondary peak among secondary peaks detected by all the correlation processing as an optimum M sequence.

Abstract: Disclosed herein is an apparatus and method to track positions of multiple sound sources which can simultaneously track the positions of multiple sound sources. Sound signals input to an array of microphones are separated into independent sound source signals, correlation coefficients between the sound signals input to the microphones and the separated sound source signals are estimated, and the estimated correlation coefficients are analyzed to track the positions of the sound sources.

Abstract: A method for determining position of a mobile electronic device includes emitting an acoustic pulse from the position of the mobile electronic device. The acoustic pulse is detected at a known position at three spaced apart locations along each of at least two lines extending in different directions. The range and phase difference of the acoustic pulse between each of the detecting locations is determined. A relative position of the device with respect to the known position is obtained from the range and phase differences.

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: 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: There is provided a sonic wave output device comprising, a receiving unit to receive wireless signals transmitted from a certain signal source, a determination unit to determine a parameter value depending on a location of the signal source using the wireless signals received by the receiving unit and a sonic wave output unit to output sonic waves with directionality toward a direction of the signal source based on the parameter value.

Abstract: In one aspect, a method to determine multipath angles of arrival includes performing an autocorrelation on a first signal received at a first received beam from a signal source, performing a cross-correlation between the first signal and a second signal received at a second receive beam from the signal source, and determining an angle of arrival for a first path from the signal source and an angle of arrival for a second path from the signal source based on the autocorrelation and the cross-correlation.

Abstract: Downhole positioning systems and associated methods are disclosed. In some embodiments, the system comprises a downhole source, an array of receivers, and a data hub. The downhole source transmits an electromagnetic positioning signal that is received by the array of receivers. The data hub collects amplitude and/or phase measurements of the electromagnetic positioning signal from receivers in the array and combines these measurements to determine the position of the downhole source. The position may be tracked over time to determine the source's path. The position calculation may take various forms, including determination of a source-to-receiver distance for multiple receivers in the array, coupled with geometric analysis of the distances to determine source position. The electromagnetic positioning signal may be in the sub-hertz frequency range.

Abstract: A method of locating a sound source based on sound received at an array of microphones comprises the steps of determining a correlation function of signals provided by microphones of the array and establishing a direction in which the sound source is located based on at least one eigenvector of a matrix having matrix elements which are determined based on the correlation function. The correlation function has first and second frequency components associated with a first and second frequency band, respectively. The first frequency component is determined based on signals from microphones having a first distance, and the second frequency component is determined based on signals from microphones having a second distance different from the first distance.

Abstract: A signal processing apparatus includes: a learning processing unit that finds a separating matrix for separating mixed signals in which outputs from a plurality of sound sources are mixed, by a learning process that applies ICA (Independent Component Analysis) to observed signals including the mixed signals; a separation processing unit that applies the separating matrix to the observed signals to separate the mixed signals and generate separated signals corresponding to each of the sound sources; and a sound source direction estimating unit that computes a sound source direction of each of the generated separated signals.

Abstract: A “Sensor Array Post-Filter” provides an adaptive post-filter that accurately models and suppresses both diffuse and directional noise sources as well as interfering speech sources. The post-filter is applied to an output signal produced by a beamformer used to process signals produced by a sensor array. As a result, the Sensor Array Post-Filter operates to improve the signal-to-noise ratio (SNR) of beamformer output signals by providing adaptive post-filtering of the output signals. The post-filter is generated based on a generative statistical model for modeling signal and noise sources at distinct regions in a signal field that considers prior distributions trained to model an instantaneous direction of arrival for signals captured by sensors in the array.

Abstract: A method and apparatus for detecting an aircraft. The method is provided for wide area tracking of aircraft. An acoustic emission of the aircraft is detected from a plurality of locations. A position of the aircraft at a set of times is estimated by comparing a set of harmonically related Doppler shifted frequencies for the acoustic emission to an expected zero Doppler shifted frequency of the aircraft to form an estimated position. The position of the aircraft and a heading of the aircraft are tracked using the estimated position. The aircraft type is classified based on the corresponding set of zero Doppler frequencies at each acoustic sensor.

Abstract: A dual-receiving ultrasonic distance measuring equipment is disclosed, which uses a transmitter and two receivers, one of which serves as an objective and the other as a reference, to perform distance measurement. The transmitter and the reference receiver are fixedly installed on a phase adjusting platform, capable of adjusting a reference phase by fine-tuning the distance between the transmitter and the reference receiver. As the objective receiver is disposed on an object under measurement which is a distance away from the phase adjusting platform, there will be a phase shift due to the propagation of an ultrasonic wave from the transmitter as it is received by the two receivers. And thereby, the distance between the two receivers can be calculated based on the phase shift. The aforesaid ultrasonic distance measuring equipment can be applied in the positioning system of high precision machinery or other non-contact distance measuring system.

Abstract: In a positional information detecting device, a tone-burst signal propagating unit causes a tone-burst signal to propagate through a path. The tone-burst signal is composed of a continuous wave train, the continuous wave train including a plurality of cycles of a constant frequency. A detecting unit detects, at a predetermined position in the path, the tone-burst signal propagating through the path every one cycle of the tone-burst signal to measure a propagation delay time based on the detected signal. The propagation delay time represents a period for which the tone-burst signal has propagated through the path. A phase obtaining unit obtains a phase of the detected signal. A positional information obtaining unit obtains positional information associated with the predetermined position based on the measured propagation delay time and the obtained phase of the detected signal.

Abstract: Systems and methods determine the location of a microphone with an unknown location, given the location of a number of other microphones by determining a difference in an arrival time between a first audio signal generated by and microphone with a known location and a second audio signal generated by another microphone with an unknown location, wherein the first and second audio signals are a representation of a substantially same sound emitted from an acoustic source with a known location; determining, based on at least the determined difference in arrival time, a distance between the acoustic source with the known location and the microphone with the unknown location; and determining, based on the determined distance between the acoustic source with the known location and the microphone with the unknown location, the location of the unknown microphone.

Abstract: A system and method for detecting, identifying, and fixing the location of the source of an acoustic event. The inventive system includes: a plurality of sensors dispersed at somewhat regular intervals throughout a monitored area; a communication network adapted to deliver information from the sensors to a host processor; and a process within the host processor for determining, from the absolute times of arrival of an event at two or more sensors, a position of the source of the event. Acoustic events are detected and analyzed at each sensor so that the sensor transmits over the network: an identifier for the sensor; an identifier for the type of event; and a precise absolute time of arrival of the event at the sensor. In a preferred embodiment, the system also identifies the type of weapon firing a gunshot.

Abstract: A “Sensor Array Post-Filter” provides an adaptive post-filter that accurately models and suppresses both diffuse and directional noise sources as well as interfering speech sources. The post-filter is applied to an output signal produced by a beamformer used to process signals produced by a sensor array. As a result, the Sensor Array Post-Filter operates to improve the signal-to-noise ratio (SNR) of beamformer output signals by providing adaptive post-filtering of the output signals. The post-filter is generated based on a generative statistical model for modeling signal and noise sources at distinct regions in a signal field that considers prior distributions trained to model an instantaneous direction of arrival for signals captured by sensors in the array.

Abstract: A sound determination apparatus receives acoustic signals by a plurality of sound receiving units, and generates frames having a predetermined time length. The sound determination apparatus performs FFT on the acoustic signals in frame units, and converts the acoustic signals to a phase spectrum and amplitude spectrum, which are signals on a frequency axis, then calculates the difference at each frequency between the respective acoustic signals as a phase difference, and selects frequencies to be the target of processing. The sound determination apparatus calculates the percentage of frequencies at which the absolute values of the phase differences of the selected frequencies are equal to or greater than a first threshold value, and determines that the acoustic signal coming from the nearest sound source is included in the frame when the calculated percentage is equal to or less than a second threshold value.

Abstract: An array of three-axis magnetometers used for dynamic magnetic anomaly compensation are located at the corners of a parallelopiped, with pairs of magnetometer outputs used to derive a magnetic anomaly gradient vector used to compensate a compass and/or the output of a gyroscope in an inertial management unit. The system may be used in a neutrally buoyant remotely operated vehicle to permit ascertaining of course and position in the absence of surface control signals.

Abstract: A new approach to capturing and reproducing either live or recorded three-dimensional sound is described. Called MTB for “Motion-Tracked Binaural,” the method employs several microphones, a head tracker, and special signal-processing procedures to combine the signals picked up by the microphones. MTB achieves a high degree of realism by effectively placing the listener's ears in the space where the sounds are occurring, moving the virtual ears in synchrony with the listener's head motions. MTB also provides a universal format for recording spatial sound.

Abstract: A to method and system provide a range and depth localization of a passive sound generator, e.g., a submarine target. The method and system use an autocorrelation and/or a cross correlation to arrive at a plurality of range versus depth estimates, which are resolved and evaluated using likelihood factors in order to provide a range and depth localization.

Abstract: Measuring apparatus for providing information on the relative location of a target site which is radiating a target signal that includes a predetermined pulse signal, comprises receiver means for providing a pair of temporally spaced output pulses in response to a single received said predetermined pulse signal and cross-correlation means coupled to said receiver means for cross-correlating said pair of output pulses or signals derived therefrom.

Abstract: The present invention is directed to a sonar system that includes a transmitter configured to direct multi-frequency transmit signals into a propagation channel. Each multi-frequency transmit signal includes a first frequency and a second frequency. A receiver is tuned to receive multi-frequency return signals propagating in the propagation channel. Each multi-frequency return signal includes a first frequency return signal and a second frequency return signal. The first frequency return signal has a first phase and the second frequency return signal having a second phase. A signal processor is coupled to the receiver. The signal processor is configured to extract the first phase and the second phase from the multi-frequency return signal and calculate a phase difference. The phase difference is the difference between the first phase and the second phase.

Abstract: The invention relates to a method and device for generating data about the mutual position of at least three acoustic transducers. The aim of the invention is to make it possible to continuously measure and calculate the mutual position of at least three acoustic transducers, particularly the rotation and the position of a human head wearing headphones within a room without using any additional transmitter element on the head, headphone, or body of the listener, during audio playback. This aim is achieved by connecting the acoustic transducers to a digitally operated system which comprises an output path emitting audio signals to first and second acoustic transducers, an input path receiving audio signals from the third acoustic transducer, an audio signal source that is connected to the output path, an ultrasound generator that is connected to the output path, and an information generator which indicates a position and is connected to the input path.

Abstract: A circuit coupled to an array antenna, such as a sonar transducer array, for measuring the angle of orientation of an incident wave of radiation is formed of first and second channels coupled to respective portions of the antenna to sense delays between signals of the two channels. A memory retains data of earlier occurring lead and lag measurements. Any subsequent transition from a lead/lag to a lag/lead within a single signal pulse is sensed by a gating circuit which disgards the measurement so as to provide noise immunity.

Abstract: There are provided a speaker distance detection apparatus and method using a microphone array, capable of exactly detecting the distance between a speaker and even a small terminal such as a mobile telephone, and a speech input/output apparatus using the method. The speaker distance detection apparatus uses a microphone array composed of a plurality of microphones, previously determines a reference microphone to be a reference among a plurality of microphones, detects differences between a signal level of the reference microphone and signal levels of the other microphones, based on correlations between signals in the respective microphones, and determines the distance from the microphone array to the speaker based on the detected signal level difference.

Abstract: A passive sound telemetry system and method is provided, in which phase differences are calculated for every pulse from acoustic signals received via three or six acoustic receivers, to measure a distance and angle with respect to a sound source. The system is applied to an operating toy giving chase to a user while following the user command.

Abstract: The invention relates to a device that is used to analyse the structure of a material. The inventive device comprises: probe elements (5) which are used to (i) emit a wave, in the material, with emission delay laws that correspond to several simultaneous deviations and (ii) receive, on the different probe elements (5), signals from the refraction of said wave by the material; detection channels, each detection channel being connected to a probe element (5), in order to collect the refraction signals and to transmit same to data processing means (4); and delay circuits that apply a delay on each detection channel according to the reception delay laws which are predetermined and which correspond to the different deviations of the wave emitted. The invention also relates to an analysis method which can be used, in particular, on said device.

Abstract: In order to locate and display the source of a sound such as a noise at a factory or the like accurately even when it is outside, a pair of microphones (M1, M3) and another pair of microphones (M2, M4) are disposed on the X axis and Y axis with a distance L therebetween, respectively, the direction of the sound source is estimated from a difference between sound arrival times to the microphones (M1, M3) and a difference between sound arrival times to the microphones (M2, M4), an image around the estimated location of the sound source is picked up by a camera, and the above estimated location of the sound source is displayed on the above image displayed on the display of a personal computer.

Abstract: A system for close range sonar is provided. The system provides sufficient warning to permit maneuvering to avoid a close encounter even in the forward starboard/port regions, which have been problematic in the past due to ownship noise. The system utilizes a hull mounted sonar array and a towed sonar array which may be controlled in position to provide sufficient separation of noise received by both sonar arrays such that the noise is largely uncorrelated. The system utilizes beamformers for each array to supply a cross-correlator section which is able to minimize the ownship noise and maximize the signal thereby providing more time for maneuvering. The system also provides a LOFAR display and other displays that are highly sensitive to detecting close encounters.

Abstract: A double feed detecting apparatus provided with an ultrasonic transmitter installed on one side of a transport path for a sheet material for transmitting an ultrasonic toward the sheet material, an ultrasonic receiver installed on the other side of the transport path for the sheet material for receiving the ultrasonic transmitted by the ultrasonic transmitter and outputting a received ultrasonic signal, a first determining device for determining whether double feed or not in accordance with the amplitude of the received ultrasonic signal output by the ultrasonic receiver, and a second determining device for detecting a phase change in the received ultrasonic signal, and determining whether double feed or not on the basis of the detected phase change.

Abstract: An apparatus (10) for detection of multiple documents (42) in a document transport system comprises a first transmitter (13) emitting a first signal at a first interval through a document feed path (40). A first sensor (14) detects the first signal from the first transmitter (13). A second transmitter (15) emits a second signal at a second interval through the document feed path (40). A second sensor (16) detects the second signal from the second transmitter (15).

Abstract: A system for determining the position of a transponder transmitting a signal and moving along a route is disclosed. The route includes a measuring station with at least two measuring points having on each side of the route and along a line generally perpendicular to the route. The measuring station includes a first receiver that receives the signal at one measuring point and a second receiver that receives the signal at the other measuring point. Each receiver provides an output. A circuit measures the phase difference between the outputs of the first and second receivers, and the transponder location along the line between the measuring points is determined based on the measured phase difference.

Abstract: An inclination angle measurement apparatus includes a first ultrasonic sensor (3) for sending an ultrasonic wave toward a reflective object (2), second and third ultrasonic sensors (4 and 5) each for receiving an ultrasonic wave reflected from the reflective object (2), and a calculation control circuit (14) for calculating an angle of inclination of a moving object with respect to the reflective object (2) based on a phase difference between ultrasonic waves received by the second and third ultrasonic sensors (4 and 5). Thus the inclination angle measurement apparatus can accurately measure the angle of inclination of the moving object with respect to the reflective object (2).

Abstract: The position and orientation of a mobile unit is determined from ultrasonic waves received from beacons of known location. Orientation is determined from a phase difference of the sensed ultrasonic wave at plural receivers on the mobile unit. Signals from multiple beacons may be processed to solve for x, y and z position and for speed of sound. The receivers are spaced at greater than a half wavelength of the ultrasonic wave and signals from plural receivers are processed to remove multiple wavelength phase ambiguity. Two non-collinear sets of collinear receivers allow ambiguity resulting from symmetry of the receivers to be broken.

Abstract: An acoustic spectra personal identification system comprising acoustic signal generating means, acoustic transducer means and computer means including storage means, processor means and acoustic signal analysis means, whereby a data base may be generated and maintained that stores acoustic resonance spectrum information specific to selected body parts of known individuals, for comparison against newly captured acoustic resonance spectral information obtained from an identification subject and for determination whether said subject's acoustic spectra matches that of a data base participant.

Abstract: An inclination angle measurement apparatus includes a first ultrasonic sensor (3) for sending an ultrasonic wave toward a road surface (2), second and third ultrasonic sensors (4 and 5) each for receiving an ultrasonic wave reflected from the road surface (2), and a calculation control circuit (14) for calculating an angle of inclination of a vehicle with respect to the road surface (2) based on a phase difference between ultrasonic waves received by the second and third ultrasonic sensors (4 and 5). Thus the inclination angle measurement apparatus can accurately measure the angle of inclination of the vehicle with respect to the road surface (2).

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.