119 results about "Infrasound" patented technology

Systems and methods for noise suppression using noise subtraction processing are provided. The noise subtraction processing comprises receiving at least a primary and a secondary acoustic signal. A desired signal component may be calculated and subtracted from the secondary acoustic signal to obtaining a noise component signal. A determination may be made of a reference energy ratio and a prediction energy ratio. A determination may be made as to whether to adjust the noise component signal based partially on the reference energy ratio and partially on the prediction energy ratio. The noise component signal may be adjusted or frozen based on the determination. The noise component signal may then be removed from the primary acoustic signal to generate a noise subtracted signal which may be outputted.

Methods are disclosed employing seismic waves having infrasonic frequencies in the range of about 0.1–20 Hz for generating electromagnetic waves of similar infrasonic frequency in hydrocarbon bearing subterranean formations located at depths up to about 5000 meters, said electromagnetic waves having sufficient voltage amplitudes for detection at the earth's surface. Also disclosed are seismic sources capable of generating infrasonic seismic waves of sufficient amplitude for generating electromagnetic waves in hydrocarbon bearing formations at depths up to 5000 meters, said electromagnetic waves having voltage amplitudes sufficient for detection at the earth's surface.

The invention relates to an active noise reducing method and an active noise reducing device, in particular to active noise reduction for noise generated by importing and exporting wind gate of electrical equipments. The characteristics of amplitude, frequency and phase of noise of noise source are detected through sampling the noise signal. A signal with the same amplitude and reverse phase is generated through filtering and anti-phase processing and output through a speaker to counteract the noise signal so as to achieve the object of noise reduction, wherein the filtered signal is modified adaptively during filtering process so that the filtered signal is closer to the noise source signal while filtering the noise, thus the effect of noise reduction is more ideal.

Cardiac Output (CO) has traditionally been difficult, dangerous, and expensive to obtain. Surrogate measures such as pulse rate and blood pressure have therefore been used to permit an estimate of CO. MEMS technology, evolutionary computation, and time-frequency signal analysis techniques provide a technology to non-invasively estimate CO, based on precordial (chest wall) motions. The technology detects a ventricular contraction time point, and stroke volume, from chest wall motion measurements. As CO is the product of heart rate and stroke volume, these algorithms permit continuous, beat to beat CO assessment. Nontraditional Wavelet analysis can be used to extract features from chest acceleration. A learning tool is preferable to define the packets which best correlate to contraction time and stroke volume.

A sensor, sensor pad and sensor array for detecting infrasonic signals in a living organism is provided. The sensor, sensor pad and / or array can be utilized for detecting, determining and / or diagnosing level of stenosis, occlusion, or aneurysm in arteries, or other similar diagnosis. The sensor can include unique circuitry in the form of a piezoelectric plate or element sandwiched between two conductive O-rings.

Systems and methods for adaptive processing of a close microphone array in a noise suppression system are provided. A primary acoustic signal and a secondary acoustic signal are received. In exemplary embodiments, a frequency analysis is performed on the acoustic signals to obtain frequency sub-band signals. An adaptive equalization coefficient may then be applied to a sub-band signal of the secondary acoustic signal. A forward-facing cardioid pattern and a backward-facing cardioid pattern are then generated based on the sub-band signals. Utilizing cardioid signals of the forward-facing cardioid pattern and backward-facing cardioid pattern, noise suppression may be performed. A resulting noise suppressed signal is output.

The invention discloses a self-adaptive active noise reduction method for an error-free microphone. According to the method, only one reference microphone is used for achieving active noise reduction;the method comprises the steps that firstly, transfer functions of a main channel and a secondary channel are estimated in advance, an error signal of a target noise-reduction point is estimated in real time by utilizing a received reference signal, and then weight coefficient vectors of a feedforward filter and a feedback filter are updated by using the error signal; the output of the feedforward filter and the output of the feedback filter are superimposed to obtain the output of an infrasound source. By means of the method, an error microphone required in a traditional self-adaptive activenoise reduction method is not needed, the problems of insufficient algorithm stability, complicated earphone structure and the like generally existing in traditional self-adaptive active noise reduction can be solved, and therefore the applicability and stability of the self-adaptive active noise reduction algorithm are greatly improved.

Null processing noise subtraction is performed per sub-band and time frame for acoustic signals received from multiple microphones. The acoustic signals may include a primary acoustic signal and one or more additional acoustic signals. A noise component signal may be determined for each additional acoustic signal in each sub-band of signals received by N microphones by subtracting a desired signal component within every other acoustic signal weighted by a complex-valued coefficient σ from the secondary acoustic signal. The noise component signals, each weighted by a corresponding complex-valued coefficient α, may then be subtracted from the primary acoustic signal resulting in an estimate of a target signal (i.e., a noise subtracted signal).

The invention discloses a system for monitoring, forecasting and warning the mud-rock flow, comprising at least one rainfall monitoring station, at least one mud-rock level monitoring station, at least one infrasound monitoring station and an integrated control center. The rainfall monitoring station is arranged in the mud-rock forming area; the mud-rock level monitoring station is arranged on the monitoring section; the infrasound monitoring station is arranged in the mud-rock flow flowing area; and the integrated control center is interacted with the rainfall monitoring station, the infrasound monitoring station, the mud-rock level monitoring station and the like. When the system operates, the rainfall monitoring station, the infrasound monitoring station and the mud-rock level monitoring station are used for automatically acquiring related monitoring index data and sending the related monitoring index data to the integrated control center, and the integrated control center is used for displaying the curve change process and the monitoring index data storage process in real time on line and integrally confirming and releasing the mud-rock flow forecasting and warning scheme. The system can be used for monitoring, forecasting and warning the formation, the movement and the development of the mud-rock flow as soon as possible so as to avoid the mud-rock flow accident, thereby having very practice value of preventing the mud-rock flow accident.

The present invention is an extremely low frequency (ELF) microphone and acoustic measurement system capable of infrasound detection in a portable and easily deployable form factor. In one embodiment of the invention, an extremely low frequency electret microphone comprises a membrane, a backplate, and a backchamber. The backchamber is sealed to allow substantially no air exchange between the backchamber and outside the microphone. Compliance of the membrane may be less than ambient air compliance. The backplate may define a plurality of holes and a slot may be defined between an outer diameter of the backplate and an inner wall of the microphone. The locations and sizes of the holes, the size of the slot, and the volume of the backchamber may be selected such that membrane motion is substantially critically damped.

Present day intrusion detection systems frequently cause false alarms by mistaking occupants as intruders, and it is desirable to reduce such false alarms. This invention comprises a processor that employs various software algorithms. The processor receives signals over temporal periods and software algorithms statistically discern various activities, thereby reducing false alarms and detection failures. The software algorithms are adaptive to the level of detected activity such that a rate of false alarms may be predetermined. As such, the processor and software algorithms comprise an artificial intelligence system. This artificial intelligence system may be employed in intruder and vehicle alarm systems composed of a multiplicity of detectors and within such detectors. A second aspect of this invention is an improved infrasound detection method that may be employed in such artificial intelligence.

Systems and methods for accelerating tissue processing by treating tissue samples and one or more tissue processing agents with infrasonic vibrations are discussed. Some non-limiting examples of tissue processing agents include a tissue fixative, dehydrating agent, clearing agent, impregnating agent, embedding agent, tissue stain, enzyme, or another chemical that diffuses into the tissue sample when the sample is being preserved or prepared for microscopic examination. The infrasonic vibrations can have a frequency from about 10 to about 600 Hz. The infrasonic vibrations can have an amplitude that is sufficiently high, when combined with the frequency, to induce turbulent mixing of the processing agent and accelerate tissue processing. The tissue sample may optionally be vibrated with ultrasonic vibrations. The ultrasonic vibrations can have a frequency and amplitude that are sufficiently high to induce turbulent mixing of the processing agent and to accelerate tissue processing.

Systems and methods are disclosed for passively detecting air turbulence using one or more infrasonic sensors mounted on an aircraft. The system may include one or more infrasonic sensors that are mounted on the aircraft and configured to detect infrasound. The system may also include a processor configured to receive output signals from the one or more infrasonic sensors and detect air turbulence away from the aircraft based on the output signals received from the one or more infrasonic sensors. The detected air turbulence may include natural or man-made turbulence including wake turbulence, clear air turbulence, mountain waves, or events such as a rocket launch.

Systems and methods for providing acoustic echo cancellation are provided. Primary and secondary acoustic signals are received by a communication device. The acoustic signals may include loudspeaker leakage. A null coefficient is then adaptively determined for each subband of the secondary acoustic signal. The null coefficient is applied to the secondary acoustic signal to generate a coefficient-modified signal. The coefficient-modified signal is subtracted from the primary acoustic signal to generate a masked acoustic signal with reduced or no echo. The masked acoustic signal may be output.

A speaker device for emitting subsonic, sonic or ultrasonic compression waves comprising a generally hollow drum, a rigid emitter plate attached to the drum, and a plurality of apertures formed within the plate which are covered by a thin piezoelectric film disposed across the emitter plate. A pressure source is coupled to drum for developing a biasing pressure with respect to the thin film at the apertures to distend the film into an arcuate emitter configuration capable of constricting and extending in response to variations in the applied electrical input at the piezoelectric film to therapy create a compression wave in a surronding environment. Parametric ultrasonic frequency input is supplied to the piezoelectric film to propagate multiple ultrasonic frequencies having a difference component corresponding to the desired subsonic, sonic or ultrasonic frequency range.

An improved fish deterrent and guide, utilizing generally a paddlewheel (1) consisting of a central shaft (10) with vanes (12) to create a behavioral modifier. When paddlewheel (1) is rotated, the action of the vanes striking the water creates water particle motion (low frequency sound or infrasound), turbulence and current, as well as visual cues that fish avoid. The device is tunable for different fish species and life stages by adjustment of vane style, spacing, and paddlewheel rotation speed. The use of multiple behavioral deterrents creates a measure of reliability in the system. Another advantage is that this fish deterrent provides a continuous lead, which is more effective than typical point-source turbulence and sound generators. Typically, the paddlewheel fish deterrent and guide is positioned at the water surface across the intake to a power plant intake to deter surface oriented downstream migrating fish, and guide them to a bypass. In this configuration floating debris is also guided through the bypass. Alternatively, the paddlewheel may be positioned at a subsurface elevation to guide non surface oriented fish to the bypass, or positioned across the tailrace to guide upstream migrating fish to a fishway entrance.

The present invention relates to inspection of medical patients including, but not limited to, phonocardiography, auscultation and ultrasound medical imaging and other non-acoustical inspection techniques; and industrial non-destructive testing and evaluation of materials, structural components and machinery; and more particularly to the incorporation of cognitive artificial intelligence into an inspection system and method that utilizes cognitive mathematical techniques which emulate the cognitive processing abilities of the human brain including, but not limited to, symbolic cognitive architectures and inference process algebras, to analyze data collected from infrasound acoustical sensors (0.1 Hz-20 Hz), audible acoustical sensors (20 Hz to 20 kHz), ultrasound acoustical sensors and transmitters above 20 kHz, data collected from other non-acoustical inspection devices and systems including, but not limited to electrocardiography (EKG), computed-tomography (CT), single photon emission computed tomography (SPECT), positron emission tomography (PET), magnetic resonance imaging (MRI), electromagnetic testing (ET), magnetic particle inspection (MT or MPI), magnetic flux leakage testing (MFL), liquid penetrant, radiographic (x-ray and gamma ray), eddy-current testing, low coherence interferometry, and combinations thereof (i.e., multi-modality inspection data); fuse this data resulting in the generation of new metadata; and then utilize cognitive mathematical techniques to interpret this data against inspection signatures that characterize conditions being diagnosed. The present invention has the ability to also identify and anticipate abnormal conditions that fall outside known inspection signature patterns; and communicate the inspection results to an operator thereby simplifying the initial inspection and diagnosis for medical patients and industrial objects; minimizing false negative and false positive initial inspection results and lowering costs.

A method and system for remotely inspecting the integrity of a structure. This can be performed by a method creating a vibratory response in the structure from a remote location and then measuring the vibratory response of the structure remotely. Alternatively, this can be performed by a system for remotely measuring the integrity of a structure using a vehicle and an artificial neural network, where the vehicle is equipped with a vibratory response device. The vibratory response can be produced by infrasonic and audio frequencies that can be produced by at least a vehicle, motor, or sound recording. The vibratory response can be measured with a laser vibrometer or an audio recording device.

Various embodiments may provide an airborne system for measuring meteorological parameters, including a high altitude unmanned aerial vehicle (UAV) formed completely or partially of closed-cell polyurethane foam. In various embodiments, the UAV may include extendable wings configured to extend and retract as the UAV climbs and descends to different altitude levels. In various embodiments, the UAV may include one or more infrasonic sensors and wind screening configured to measure one or more meteorological parameters, such as wind shear, seismic waves, magnetic storms, magnetohydrodynamic waves, severe weather, tornadoes, hurricanes, meteors, and lighting. The infrasonic sensors may be configured to determine wind shear at the local and regional level. In various embodiments, other meteorological sensors may also be included in / on the UAV in addition to the infrasonic sensors.

A drive apparatus and heat dissipating apparatus for a vibrating diaphragm coil of a speaker, a mobile terminal and heat dissipating method, the heat dissipating apparatus includes: a control unit configured to output an enabling signal to trigger an audible sound drive circuit to work when judging the speaker is in a sounding state, and output an enabling signal to trigger an non-audible sound drive circuit to work if the speaker is in a non-sounding state; the audible sound drive circuit configured to, after being enabled by the control unit, amplify a received audio signal, then drive the vibrating diaphragm coil of the speaker to vibrate; and the non-audible sound drive circuit configured to, after being enabled by the control unit, drive the vibrating diaphragm coil of the speaker to vibrate and control the vibration frequency of the vibrating diaphragm coil to be human ear non-audible ultrasonic or infrasonic frequency.

The infrasound generating device based on a displacement-feedback type vibration exciter comprises a displacement-feedback type vibration exciter system, an infrasound generating chamber (3) and a laser vibrometer (1); the displacement feedback mechanism is adopted in the vibration exciter (2). The piston (31) is driven by the vibration exciter to move in a sinusoidal manner in the cavity (35) of the airtight infrasound generating chamber (3) and the standard infrasonic pressure signal with low harmonic distortion can be achieved. The displacement of the moving part (22) of the vibration exciter (2) can be measured by the laser vibrometer (1) through the measurement beam (15) injecting into the vibration exciter (2) through the optical channel running through the vibration exciter and the standard infrasonic pressure can also be obtained. The value of the standard sound pressure produced by the infrasound generating chamber is calculated. Such value is used as the calibration reference for the infrasound sensors (4) to be calibrated in order to achieve the primary calibration of the infrasound sensors. The standard infrasonic sensor can be installed inside the infrasound generating chamber (3) and the output of the standard infrasonic sensor can be used as the reference for the infrasonic sensor (4) to be calibrated in order to achieve the secondary calibration of the infrasound sensors. This invention has the advantages of technical maturity, high feasibility, easy to realize, high calibration accuracy and so on.

A windscreen is configured for measuring outdoor infrasonic sound. The windscreen includes a container and a microphone. The container defines a chamber. The microphone is disposed in the chamber and can be operatively supported by the floor. The microphone is configured for detecting infrasonic sound. The container is advantageously formed from material that exhibits an acoustic impedance of between 0 and approximately 3150 times the acoustic impedance of air. A reflector plate may be disposed in the container. The reflector plate operatively can support the microphone and provides a doubling effect of infrasonic pressure at the microphone.

An infrasound absorbing structure is simple in construction and is capable of effectively controlling infrasonic noises. The infrasound absorbing structure is applied to an engine test cell or an engine runup hangar to reduce infrasonic noises generate therein. The infrasound absorbing structure includes a porous layer facing an infrasound source, and a back wall disposed opposite to the porous layer so as to define a back air layer of a thickness between 2 and 10 m between the porous layer and the back wall. The porous layer has a surface density in the range of 0.5 to 10 kg / m2.