Abstract: A system configured to perform sound source localization (SSL) using reflection detection is provided. A device processes audio data from multiple microphones to determine timing information corresponding to sound sources. For example, the device may determine cross-correlation data for each microphone pair, determine autocorrelation data for each microphone, and then use the autocorrelation data and the cross-correlation data to calculate quality factors. The device may determine the direction of potential sound source(s) by generating Steered Response Power (SRP) data using the cross-correlation data. To perform reflection detection to distinguish between direct sounds and acoustic reflections, the device may generate modified SRP data using the quality factors.

Abstract: Disclosed are techniques for a multimedia device with audio and video capturing capability to identify an audio device based on acoustic playback signal if the audio device cannot be identified from captured video. The multimedia device may assemble a list of candidate audio devices that are a possible match for the observed audio device from a database of previously recognized audio devices and may transmit commands to the candidate audio devices to play acoustic identification signals. The acoustic identification signals may be audible sound or ultrasonic tone sequences with embedded identification information unique to each audio device. The multimedia device may record and analyze the acoustic identification signals received from any of the candidate audio devices to construct metrics to select the most likely candidate for the observed audio device. The metrics may include time of flight, direction of arrival, received amplitude, direct-to-reverberant ratio (DRR) of the acoustic identification signals.

Abstract: An air-coupled ultrasonic interferometric method is disclosed. An air-coupled ultrasonic transducer, as a probe, is placed directly facing the surface of a workpiece, and an ultrasonic wave is reflected back and forth between the ultrasonic transducer and the surface of the workpiece; the phase difference of the first echo reflected from the surface of the workpiece and reaching the air-coupled ultrasonic transducer is measured; based on the change of the ultrasonic frequency and wavelength, the measured distance is transformed into the rate of change of the acoustic phase with respect to the acoustic angular frequency, wherein the change in the acoustic angular frequency is a product obtained by multiplying 2? by the difference between the highest frequency F2 and the lowest frequency F1 within the bandwidth fB of the air-coupled ultrasonic transducer.

Abstract: The invention discloses a target tracking method applied to a video transmission, which can automatically track a specific target and capture images according to sound. The target tracking method includes the following steps: step one is to set a first target area; step two is to determine whether a corresponding sound source position points to the first target area according to a sound source position signal; step three is to capture an image of the first target area and output to a display unit by a camera unit when the sound source position points to the first target area; and step four is to execute a sound source tracking procedure when the sound source position is not pointing to the first target area.

Abstract: A sensor for monitoring a monitoring area having a transmitter for transmitting radiation into the monitoring area for reflection at an object in the monitoring area, a test transmitter for transmitting a test signal comprising radiation, a receiver for receiving the radiation of the transmitter that is reflected at the object or the radiation of the test transmitter, and an evaluation device for ascertaining a distance value on the basis of the delay in the transit time or the phase of a modulation between the transmitted and received radiation of the sensor. The sensor further comprises a memory for storing an expectation value for the expected distance value of the received test signal, and a comparison device for comparing a distance value on the basis of the received test signal with the expectation value and for outputting a safety signal on the basis of the comparison.

Abstract: The present invention discloses a method and a system for navigating an Autonomous Ground Vehicle (AGV) using a radio signal and a vision sensor. The method comprising generating a trajectory plan for a short distance from a path plan, wherein the path plan is determined using destination location and AVG location, identifying an approximate AGV location using a radio signal-based trilateration mechanism, estimating AGV location error with respect to a road lane center by determining distance from the approximate AGV location to road boundary and road lane marking line and orientation difference between AGV orientation and road orientation, and correcting the trajectory plan by using the estimated AGV location error for navigating an AGV.

Abstract: Various implementations directed to quality control and preconditioning of seismic data are provided. In one implementation, a method may include receiving particle motion data from particle motion sensors disposed on seismic streamers. The method may also include performing quality control (QC) processing on the particle motion data. The method may further include performing preconditioning processing on the QC-processed particle motion data. The method may additionally include attenuating noise in the preconditioning-processed particle motion data.

Abstract: A system includes first, second, and third microphones configured to receive sound waves from a source of the sound waves. The system includes a memory configured to store first, second, and third phase difference maps for the first and second microphones, the second and third microphones, and the third and first microphones. The system includes a processor configured to measure first, second, and third phase differences between the sound waves received from the source by the first and second microphones, the second and third microphones, and the third and first microphones; receive the first, second, and third phase difference maps from the memory; and identify a location of the source of the sound waves based on the first, second, and third phase differences and the first, second, and third phase difference maps for the first and second microphones, the second and third microphones, and the third and first microphones.

Abstract: A device having two mutually spaced sensor loops is provided. The device includes a magnetostrictive sensor structure coupled to a plurality of transmitters and a plurality of receivers, and along which a magnet that is secured to the rotating component moves. Each sensor loop has a shape corresponding to a rotating direction of the rotating component. Two saturation zones are in both sensor loops. Each transmitting element is provided for simultaneously coupling two current pulses in opposite direction into one respective sensor loop. Each receiving element is positioned to receive a reflected pulse by the magnet at the respective saturation zone.

Abstract: A method for controlling secure access to user requested data includes retrieving information related to potential unauthorized access to user requested data. The information is collected by a plurality of sensors of user's mobile device. A trained statistical model representing an environment surrounding a user is generated based on the retrieved information. A first data security value is determined using the generated trained statistical model. The first data security value indicates a degree of information security based on user's environment. A second data security value is determined using the generated trained statistical model. The second data security value indicates a degree of confidentiality of the user requested data. The user requested data is filtered based on a ratio of the determined first data security value and the second data security value.

Abstract: A method includes emitting, by a single sensor of a device, a signal into a region; receiving, by the single sensor, a reflected signal; and detecting motion in a detection cone comprising a central axis based on the reflected signal, wherein detecting motion comprises detecting a first type of motion from a first position to a second position, and detecting a second type of motion from the second position to the first position.

Abstract: This wave source direction estimation apparatus is capable of highly accurately estimating the direction of a wave source even in an environment with a high surrounding noise level, and is provided with: a plurality of input signal acquisition means for acquiring signals generated at a wave source as input signals; a correlation function calculation means for calculating correlation functions on the basis of the input signals acquired by the input signal acquisition means; an envelope function extraction means for extracting envelope functions on the basis of the calculated correlation functions; a combined envelope function calculation means for calculating a combined envelope function by combining the extracted envelope functions; and an estimated direction information generation means for generating estimated direction information about the wave source on the basis of the calculated combined envelope function.

Abstract: In one example, a video endpoint obtains, from a vertical microphone array, a first audio signal including audio from a target sound source and audio from a horizontally-displaced sound source. The video endpoint obtains, from a horizontal microphone array, a second audio signal and a third audio signal both including the audio from the target sound source and the audio from the horizontally-displaced sound source. Based on the second audio signal and the third audio signal, the video endpoint determines at least one of a first degree of arrival of the audio from the target sound source or a second degree of arrival of the audio from the horizontally-displaced sound source. Based on the at least one of the first degree of arrival or the second degree of arrival, the video endpoint adjusts a gain of the first audio signal.

Abstract: A beamforming system comprises an input module, a phase-difference module, a delay distribution module, and a delay estimation module configured to make a final delay estimation based on the delay distribution. The final delay estimation is applied to align one of two selected channels and combine the two channels to obtain a signal of interest. The phase-difference module calculates phase differences for a range of frequency bins. The delay estimation module considers all possible delays derived from the phase differences, including multiples of ±2? to overcome the ambiguity in high frequency bins when the spacing between two acoustic sensors is longer than the half of the wavelengths.

Abstract: An apparatus configured to obtain a plurality of phase differences is provided. Each phase difference represents a difference in phase between a spectral component in a first sound signal and a corresponding spectral component in a second sound signal, to estimate an aliasing frequency. Phase differences in frequency bands above the aliasing frequency are expected to be wrapped, and to unwrap the plurality of phase differences in dependence on the estimated aliasing frequency. A phase difference obtained from spectral components that are comprised in one frequency band is unwrapped independently of any phase difference obtained from spectral components that are comprised in another frequency band.

Abstract: A building automation system generates occupancy information for occupants of spaces of a building (e.g. quantity, identity and/or location of the occupants) based on occupancy sensors in the spaces. The occupancy sensors capture speech sounds originating from one or more occupants of the spaces and/or ultrasonic emissions originating from one or more user devices of the occupants are via microphone arrays. Audio data based on the captured sound is then generated. Position information for the sources of the sound is determined based on the audio data, and the audio data is enhanced based on the position information via a beamforming process. Occupancy information for the spaces is generated based on the audio data. Environmental conditions of the spaces are controlled based on the presence, absence, position, orientation, distribution and/or preferences of the occupants in the space.

Abstract: In the method for detecting a wet or damp roadway and for detecting objects, first distance signals are initially received. Thereafter, at least one object is detected if the received first distance signals correspond to a distance which is greater than or equal to a certain distance threshold value. If the received first distance signals correspond to a predefined distance which is less than the certain distance threshold value, the received first distance signals are compared to stored second distance signals. A wet or damp roadway is detected as a function of a deviation established by way of this comparison of the received and stored distance signals.

Abstract: A technique for detecting spills is described. A number of audio sensors detect a sound potentially associated with an object spilling on a surface and the audio data from the sensors is analyzed in order to generate an acoustical analysis of the sound. The analysis of the sound detected by the audio sensors is compared against a database of known sounds corresponding to a number of types of spill incidents. Based on a match detected between the analysis of the sound and a type of spill incident in the database of known sounds, the identity of the object spilled can be determined. The location of the spilled object can also be calculated by triangulating the sensor data from the audio sensors.

Abstract: Reliable detection of a microphone failure along with corrective action are provided for a portable communication device having multiple microphones. The faulty microphone detection uses a correlation based metric between three (3) or more microphones. The approach is based on full cross correlation, including phase as well as magnitude, between unique microphone pairs for isolating a faulty microphone condition. The approach allows for the determination of precisely which microphone has failed and minimizes false triggers under windy conditions within a microphone array.

Abstract: Multistatic active coherent sonar systems and methods include reception by floating receiver sonobuoys of acoustic signals emitted by floating source sonobuoys, by both direct propagation from the source sonobuoys and reflection or scattering from a target object. Subsequent calculations based at least in part on those signals can be employed to estimate relative or absolute positions or velocities of the target object and the source and receiver sonobuoys. The estimated relative velocities and positions can be calculated without relying on GPS or other extrinsic positioning signals acquired for each sonobuoy after its deployment. Acoustic signals emitted by a stationary source on the seabed, received by a stationary receiver on the seabed, or reflected/scattered from a bathymetric feature, can be employed to estimate absolute or relative positions or velocities of the target object and the source and receiver sonobuoys.

Abstract: Apparatus with I/O modules such as a networked security camera with a plurality of wireless connections to continue to use at least one network connection is presented. The apparatus, comprising a plurality of RF units, a plurality of SIM card interfaces, at least one processing unit, at least one non-transitory computer readable storage medium and at least on input/output module, is able to continue sending and receiving data through one or more wireless networks using a plurality of RF units. Further, when more bandwidth and/or higher reliability is required, the apparatus aggregates data connections established with different wireless networks.

Abstract: One or more methods for remotely estimating a drone's weight during flying are contemplated. It is possible to utilize a long range laser Doppler Vibrometer or a remote optical surveillance system. In addition, it is possible to employ a method disclosed herein using physical signatures for identifying flight characteristics and manufacturers of different drones and for monitoring drones' degradation prior to failures as a condition based maintenance system. The present teachings are applicable to drones, helicopters, and all manned and unmanned aerial vehicles.

Abstract: An implementation operable by a device coupled to a sound sensor array including a plurality of sound sensors in a particular arrangement is provided. The implementation involves obtaining a plurality of simulated responses mapping respective simulated physical arrangements of one or more simulated sound sources to respective expected outputs from the sound sensor array. The implementation also involves receiving a response based on output from the sound sensor array. The response may indicate detection of sounds from a plurality of sound sources in an environment of the sound sensor array. The implementation also involves comparing the received response with at least one of the plurality of simulated responses. The implementation also involves estimating locations of the plurality of sound sources relative to the sound sensor array based on the comparison. The implementation also involves operating the device based on the estimated locations of the plurality of sound sources.

Abstract: A method and apparatus are provided for processing data for estimating mixing parameters of at least one audio spot signal captured by a sound recording device, called a spot microphone, arranged in the vicinity of a source among a plurality of acoustic sources constituting a sound scene, and a primary audio signal captured by an ambisonic sound recording device, arranged to capture said plurality of acoustic sources of the sound scene.

Abstract: Processes are described herein for transforming an audio mixture for which a specific component is affected by reverberation, into a specific dry component (i.e. unaffected by the reverberation) and a background component. In the process described herein, the long-term effects of reverberation are explicitly taken into account by modelling the spectrogram of the specific component as the result of a matrix convolution along time between the spectrogram of the specific dry component and a reverberation matrix. Parameters of the model are estimated iteratively by minimizing a cost-function measuring the divergence between the spectrogram of the mixture signal and the model of the spectrogram of the mixture signal.

Abstract: A grammage detection sensor according to an aspect of the present invention includes a transmission unit configured to transmit an ultrasonic wave, a reception unit configured to receive the ultrasonic wave transmitted from the transmission unit, and a control unit configured to detect a grammage of a recording material, when a plurality of recording materials are continuously conveyed between the transmission unit and the reception unit, on the basis of a first ultrasonic wave received by the reception unit after the ultrasonic wave is transmitted by the transmission unit between a preceding recording material and a recording material following the preceding recording material, and a second ultrasonic wave received via a recording material by the reception unit after the ultrasonic wave is transmitted by the transmission unit.

Abstract: A data processor data processor is capable of compensating with multipath phase compensation data for a multipath phase error in the at least one subcarrier phase associated with the multipath-impacted signal arising from the transmitted OFDM-like signal. The phase compensation data results in or comprises an adjustment to the estimated range based on a direct signal vector length of a direct path signal and a multipath-impacted signal vector length of a multipath-impacted signal that are determined through observed signals or observed signal vectors of the receiver. The data processor estimates the location of the receiver or estimated range, based on the precise estimate, with the above adjustment for multipath.

Abstract: A system, method, and apparatus for drone detection and classification are disclosed. An example method includes receiving a sound signal in a microphone and recording, via a sound card, a digital sound sample of the sound signal, the digital sound sample having a predetermined duration. The method also includes processing, via a processor, the digital sound sample into a feature frequency spectrum. The method further includes applying, via the processor, broad spectrum matching to compare the feature frequency spectrum to at least one drone sound signature stored in a database, the at least one drone sound signature corresponding to a flight characteristic of a drone model. The method moreover includes, conditioned on matching the feature frequency spectrum to one of the drone sound signatures, transmitting, via the processor, an alert.

Abstract: A sound direction estimation device includes a first correlation matrix calculation unit configured to calculate a correlation matrix of a plurality of channels of input sound signals, a second correlation matrix calculation unit configured to calculate a correlation matrix of noise signals based on the plurality of channels of sound signals, and a sound source localization unit configured to calculate a spatial spectrum based on the correlation matrix calculated by the first correlation matrix calculation unit and the correlation matrix calculated by the second correlation matrix calculation unit and to estimate a direction of a sound source associated with the plurality of channels of sound signals using the calculated spatial spectrum.

Abstract: The disclosed apparatus, systems, and methods provide a calibration technique for calibrating a set of microphones. The disclosed calibration technique is configured to calibrate the microphones with respect to a reference microphone and can be used in actual operation rather than a testing environment. The disclosed calibration technique can estimate both the magnitude calibration factor for compensating magnitude sensitivity variations and the relative phase error for compensating phase delay variations. In addition, the disclosed calibration technique can be used even when multiple acoustic sources are present. The disclosed technique is particularly well suited to calibrating a set of microphones that are omnidirectional and sufficiently close to one another.

Abstract: A system and method for determining a characteristic of a noise source. A first array of microphones is mounted on a platform moveable from a starting position to an ending position along a line parallel to a central axis of the noise source. A second array of microphones includes sound sensors mounted in a spaced apart fixed position with respect to the noise source. A processing system processes first information from the first array of microphones and second information from the second array of microphones. The processing system collects and stores the first and second information at each discrete step of the first array, spatially filters the first information, processes and calibrates the filtered first information based on the second information, and further processes the calibrated first information to obtain a characteristic at a selected location. For flyover testing, the first array is instead held in a fixed position.

Abstract: Techniques are described for determining locations of audio sources. Audio signals are captured from multiple locations. Pairs of the audio signals are analyzed to create correlograms, indicating correlation scores corresponding to different time offsets between the signals. Based on the correlograms, various locations are analyzed to determine probabilities of audio originating from those locations. The highest probabilities are found, indicating locations containing audio sources. In some situations, the audio sources may be reflective sources, and the locations of the reflective sources may be used to determine locations of objects or surfaces.

Abstract: A vehicle direction identification device includes: a frequency analysis unit which analyzes amplitude or phase of surrounding sound in each analysis section; a sound source direction identification unit which identifies a sound source direction included in the surrounding sound for each analysis section; a vehicle identification information storage unit which stores first vehicle identification information including a first threshold value; a first vehicle identification unit which calculates a rate of occurrence of each sound source direction and identifies the sound source direction whose rate of occurrence is equal to or exceeds the first threshold value; a second vehicle identification information calculation unit which calculates second vehicle identification information including a second threshold value smaller than the first threshold value; and a second vehicle identification unit which identifies the sound source direction whose rate of occurrence is equal to or exceeds the second threshold value.

Abstract: There is provided a method and associated apparatus for measurement. Specifically, a method for determining a distance travelled by a signal in a medium, or the time of flight of a signal travelled. The method comprises considering an unambiguous range wherein the unambiguous range greater than a distance to be travelled by a signal. A signal is then transmitted across the distance to be determined, the signal comprising at least two frequency components, the frequency components based on the unambiguous range and the speed of the signal in the medium. The distance travelled (or the time of flight) is determined by using the variance of the received phase characteristics, such as phase angle) of one frequency component of the received signal with the received phase characteristics of another frequency component of the received signal.

Abstract: The dereverberation of signals in reverberating environments is carried out via acquiring the representation (image) of spatial distribution of the signals in space of interest and automatic identification of reflections of the source signal in the reverberative space. The technique relies on identification of prominent features at the image, as well as corresponding directions of propagation of signals manifested by the prominent features at the image, and computation of similarity metric between signals corresponding to the prominent features in the image. The time delays between the correlated signals (i.e., source signal and related reflections) are found and the signals are added coherently. Multiple beamformers operate on the source signal and corresponding reflections, enabling one to improve the signal-to-noise ratio in multi-path environments.

Abstract: In an embodiment a semiconductor device correlates a received signal with a known pattern. A correlation output is used as a basis for forming a confidence reference level. The confidence reference level and the correlation output are compared to identify a peak in the received signal indicating that a present signal state of the received signal contains the known pattern.

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 system and method is provided for resolving a pivot point via touchless interaction. It applies to situations where one end of a rigid object is inaccessible but remains stationary at a pivot point, while the other end is free to move and is accessible to an input pointing device. As an example, the rigid object can be a leg bone where the proximal end is at the hip joint and the distal end is at the knee. The system comprises a wand and a receiver that are spatially configurable to touchlessly locate the pivot point without contact. The receiver tracks a relative displacement of the wand and geometrically resolves the location of the pivot point by a spherical mapping. The system can use a combination of ultrasonic sensing and/or accelerometer measurements. Other embodiments are disclosed.

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: A system and method of touchless interaction is provided for resolving a pivot point of an object where direct placement of a sensor at the pivot point is not practical. It applies to situations where the pivot point of a rigid object is inaccessible but remains stationary, while the other end is free to move and is accessible. The system maps the object's pivot point by way of an external sensor that detects constrained motion of the rigid object within a hemispherical banded boundary. It can also detect a geometric pattern and acceleration during the constrained motion to compensate for higher order rotations about the pivot point. Other embodiments are disclosed.

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 travelled by S1 between the acoustic emitter and receiver, and the distance R2 travelled 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: 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: The transmission of a detection wave and the reception of a reflected wave are periodically repeated every transmission period. One received signal is compared with another received signal at a similar corresponding comparison periods in different transmission periods of a receiving time of the reflected wave. Switching between the comparison periods is performed each time the transmission period is updated. A waveform of a received signal in a block A0 corresponding to a reflected wave of an ultrasonic signal transmitted in a first transmission period is stored. The absolute values of differences between the waveform of a received signal in a block A1 corresponding to a reflected wave of an ultrasonic signal transmitted in a second transmission period and the stored waveform of the received signal in the block A0 are accumulated. The waveform of a received signal in a block B1 is stored.

Abstract: Systems and methods for providing audio localization are provided. In some aspects, a method includes receiving phase offsets of a plurality of fixed transmitters from a source other than the plurality of fixed transmitters, detecting an audio localization signal from each of the plurality of fixed transmitters, determining a received phase of the audio localization signal from each of the plurality of fixed transmitters, determining time differences of flight from the mobile receiver to the plurality of fixed transmitters using the received phases, determining distance differences from the mobile receiver to the plurality of fixed transmitters using the time differences of flight, and determining the location of the mobile receiver by performing multilateration using the distance differences.

Abstract: A sonar sensor array is provided that has reduced power consumption, data bandwidth and data storage requirements. The sensor array may be configured to a sleep mode, low-resolution mode and high-resolution mode. In the sleep mode, all sonar sensors are configured in the sleep mode and no acoustic signals are detected. In the low-resolution mode, a limited number of sonar sensors are powered and acoustic signals received by the sonar sensors are processed with reduced bandwidth and reduced dynamic range, and then stored on a data storage device. In the high-resolution mode, the acoustic signals detected by the sonar sensors are processed with full signal bandwidth and full dynamic range and then stored on the data storage device.

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: A signal processing unit is provided. The signal processing unit includes an orthogonal transforming part including at least two sound input parts receiving input sound signals on a time axis, the orthogonal transforming part transforming two of the input sound signals into respective spectral signals on a frequency axis, a phase difference calculating part obtaining a phase difference between the two spectral signals on the frequency axis, and a filter part phasing, when the phase difference is within a given range, each component of a first one of the two spectral signals based on the phase difference at each frequency to calculate a phased spectral signal and combining the phased spectral signal and a second one of the two spectral signals to calculate a filtered spectral signal.

Abstract: An apparatus for estimating a Direction of Arrival (DOA) of a wideband includes a first signal receiving unit and a second signal receiving unit to receive a wideband signal while satisfying d?Mc/2fs, wherein ‘d’ denotes a distance the first signal receiving unit and the second signal receiving unit are spaced apart from each other, ‘c’ denotes the speed of sound, ‘M’ denotes a number of wideband frequencies being a number of fast Fourier transformation (FFT) points of a wideband signal, and ‘fs’ denotes a sampling frequency, and a DOA calculating unit to calculate a DOA (?) using a normalized frequency ( f) which is obtained by performing an FFT on the respective wideband signals transmitted from the first signal receiving unit and the second signal receiving unit, and using the distance d.

Abstract: For precisely determining a position of an electronic pen using ultrasonic, only a direct wave arriving first at a reception device is detected without being affected by a reflected wave of an ultrasonic signal to count a propagation time of the electronic pen. An infrared signal including a trigger signal indicative of transmission timing and data indicative of an M-sequence initial condition, and an ultrasonic signal made into an M-sequence are simultaneously sent from the electronic pen in each fixed transmission cycle. The reception device disposed at a predetermined position receives the infrared signal from the electronic pen to generate an M-sequence model waveform from M-sequence initial condition data that the infrared signal includes. The reception device further receives the ultrasonic signal from the electronic pen to calculate a value of correlation between the ultrasonic signal and the above-described M-sequence model waveform.

Abstract: A loose part monitoring method and system for preventing the generation of a false alarm as much as possible, including analyzing a group of detection signals that have been output from a plurality of sensors placed on a wall defining a fluid flow path, wherein the group of detection signals are analyzed for a rising gradient that is related to change in intensity of impulsive sound, a damping time that is related to change of intensity of the impulsive sound, and a frequency spectrum that is related to pitch of the impulsive sound in order to determine whether the group of detection signals are false or true.