121 results about "Noise field" patented technology

The technology of active noise reduction (ANR) is incorporated into audiometry testing in a variety of formats. Analog feedback, digital feedback, adaptive feedforward, and adaptive feedback noise control schemes are presented for use in audiometry to reduce the ambient noise heard by the test subject, allowing subject testing in higher ambient noise fields. Audiometer test signals are appropriately compensated so the test results are accurate and comply with existing calibration standards for audiometers. Existing audiometry headphone technologies are modified so that ANR can be accomplished while satisfying existing standards for audiometric testing. Embodiments are also defined for alternate headphone arrangements that may not conform to current (1997) audiometric testing standards but provide sufficient performance advantages to warrant new standards for audiometry testing in the future.

A telephonic handset comprises an active noise reduction (ANR) system. The ANR system comprises a reference microphone and an IIR filter. The IIR filter is receivingly coupled to the reference microphone with respect to noise reference signals, and it is transmittingly coupled to the receiver transducing element of the handset. The ANR system is configured as a fixed feed-forward noise cancellation system. Preferably, the IIR filter has a transfer function derived, in part, from the open-loop gain of a feedback noise cancellation system.

In specific embodiments of the invention, the noise reference microphone is situated so as to sample the ambient noise field near the front face of the receiver, but without directly sampling the noise field on the front face.

The invention discloses a voice enhancement method employing a combination of nesting-subarray-based post filtering and spectrum-subtraction and is suitable for indoor environment, comprising the enhancement of multi-channel voice signal in vehicle environment; as the problems of unstable the broadband of the voice signals, the inconsistent frequency response of the microphone-array-based multi-channel voice-enhancement method to the voice signal and the correlation among all-channel noise in actual noise-field environment are considered, by utilizing the microphone array nested by the subarrays with different spacing, the voice signals are collected; and the voice signals formed by subarray beams are divided into a high-frequency section and a low-frequency section, different voice-enhancement algorism are adopted for carrying out the treatment; all the advantages are complementary with each other, thus improving the effect of voice enhancement.

A method for synthesizing noise in a digital image comprises the steps of (a) estimating noise statistics based on a set of spatial autocorrelation coefficients and a set of spectral correlation coefficients that correspond to the color channels of the image, where at least one of the spatial autocorrelation coefficients is weighted by at least one of the spectral correlation coefficients, thereby providing a weighted set of autocorrelation coefficients, and where a set of filter coefficients is obtained from the weighted set of autocorrelation coefficients; and (b) synthesizing a synthetic texture by using the filter coefficients to filter a random noise field in each of the color channels, thereby producing output noise fields in each of the color channels that replicate a synthetic texture, e.g., a desired grain appearance, when combined into the digital image.

Methods and apparatus for reconstructing a simulated image of an object that includes a predetermined amount of noise are provided. A method includes receiving a base image, determining an amount of noise in the base image, generating a noise field image based on the determined amount of noise in the base image, combining the noise field image and the base image to generate a simulated image that includes the predetermined amount of noise, and displaying the simulated image.

The guide device for the diffusor at the compressor impeller outlet of a radial compressor has guide blades with stepped inlet edges. The step is implemented by setting back the hub-side inlet edge. This meridional stepping divides the guide blades into two component blades, of which the first component blade is made longer than the second component blade. The set-back of the inlet edge of the hub-side component blade and the associated superposition of the noise fields which are produced on the front and rear inlet edge of the diffusor leads to improvement of the acoustic properties of the compressor.

The invention provides a line spectrum detection method by coherent accumulation of frequency domains. According to the invention, the method comprises the following steps that: step one, on the basis of time correlation characteristics of a signal field and a noise field, segment processing is carried out on a receiving signal, so that there are time delays between all segments of the signal and a time delay amount is greater than a correlation radius of the noise and is less than a correlation radius of the signal; step two, each the signal segment is internally divided into a plurality of sub data segments and it is allowed that there are overlapping parts of data of all the segments; step three, time delay compensation is carried out on the signal; step four, signals of all the segments are accumulated to obtain an output signal of coherent accumulation; step five, power equalization is carried out on outputs of all correlation accumulations, so that a power spectrum estimated by the method provided in the invention is obtained. According to the invention, coherence of signals is utilized; and phase compensation is carried out on signals, wherein there are time delay differences between all the signals; therefore, same phase addition of the signals is formed; however, because the phase of the noise is random, there is no formed same phase addition for the noise, so that a detection capability on a weak signal can be improved.

The invention relates to a submarine sound velocity passive access method based on a noise field vertical vibration velocity signal. The method comprises the steps that a marine environment noise field vector signal vertical coherent characteristic prediction model is built, aiming at three elements of inversion, an optimization algorithm, forward modeling and a cost function, a submarine sound velocity inversion model based on noise field vertical vibration velocity signal vertical coherent characteristics is given, and noise field vertical coherent characteristics are selected for conductinginversion of the submarine sound velocity. Accordingly, seawater acoustic parameters can be obtained through actual measurement, by means of a submarine geological database, geology types of the experimental seafloor can be obtained roughly, the search range of submarine parameters can be determined through table look-up, by means of a genetic algorithm, the best agreement of noise field verticalcoherent characteristic results and measured results under a group of ground acoustic parameters, and the parameters can be approximatively considered as actual submarine earth sound parameters.

A device for active noise control inside a vehicle, the device comprising a processor (7610) configured to determine a noise wavefield within the vehicle based on noise signals captured by a microphone array (M1-M10); determine the position of the ears of a passenger (P1) based on information obtained from a head tracking sensor (HTU1); capture a noise field inside the vehicle based on information obtained by the microphone array; obtain a noise level at the ears of the passenger (P1) from the noise field; and determine an anti-noise field based on the noise level at the position of the ears of the passenger.

The invention discloses a substation noise source distribution measuring method based on a synthetic aperture principle. The method comprises the following steps of adopting an array to sample substation radiation noise fields in different space positions, wherein the array consists of one group of microphones with fixed relative positions; meanwhile, fixing a plurality of reference microphones to sample the substation radiation noise fields; and then, utilizing a data processing method to synthesize the noise fields, which are sampled in different space positions by the array consisting of the microphones, through signals sampled by the reference microphones, so as to measure the substation low-frequency noise source distribution. The method is based on an array technique, and the higher angle resolution can be obtained. When one sound source is measured, the other sound sources can be effectively shielded, and the measuring precision is higher. The method has the advantage that the characteristic of the substation noise being a stable single-frequency signal is utilized, and by using the reference microphones, the small-aperture arrays in different positions are synthesized into a virtual large-aperture array, so the problem of measurement of the low-frequency noise source is effectively solved.

The invention relates to a chassis structure of a wind cooling generator unit. The invention is characterized in that the front end F of the chassis is provided with a wind inlet; a main wind duct is horizontally arranged in the wind inlet; the end of the main wind duct is provided with a clapboard which hermetically comparts the main wind duct and an wind outlet; the rear end of the chassis is provided with the wind outlet, with the exhaust direction pointing to a oblique lower part; the main wind duct is respectively provided with a first wind distributing port, a second wind distributing port and a third wind distributing port which are communicated in a casing assembly; one end of a wind guide duct is communicated with the first wind distributing port and the other end of the wind guide port is communicated with the outlet of the wind guide duct. The invention sufficiently utilizes the absorption and dispersion function of the ground to the noise, causes the noise field with strong directivity outwards radiated by the wind outlet of the generator unit to be attenuated and weakened and the noise of the whole machine is reduced; the arrangement of a plurality of wind distributing ports can ensure that all parts in the generator unit casing can be suitably cooled, the service life of corresponding parts can be prolonged, and the stability of the unit in long-term operation can be ensured.

The invention relates to a desert seismic exploration random noise eliminating method based on noise modeling analysis, and belongs to the technical field of physical geography. The desert seismic exploration random noise eliminating method comprises the following steps: building a noise-containing synthetic record; building desert seismic exploration random noise model; taking a natural noise function, a near-field human noise function, and a far-field human noise function as excitation functions of the wave function; solving a wave equation with a green function to obtain a noise field of the natural noise, a noise field of a near-field human noise and a noise field of a far-field human noise; overlapping the noise field of the natural noise, the noise field of the near-field human noiseand the noise field of the far-field human noise to obtain a desert area random noise model; and determining a proper filtering method for filtering and denoising by using the random noise model. Through adoption of the desert seismic exploration random noise eliminating method, a shearlet variable threshold denoising method finally determined based on the noise modeling is suitable for eliminating the desert seismic exploration noise; the signal-to-noise ratio of the seismic exploration data is improved; the effective signal can be recovered accurately; and the interpretation of subsequent seismic data is effectively facilitated.

The invention relates to a voice signal processing method, in particular to a voice enhancement method, which comprises the following steps of S10, audio acquisition, S20, screening effective voice signals, S30, preliminarily enhancing the voice, S40, screening target voice, S50, enhancing the voice signal again, S60, carrying out wake-up word detection: sending the re-enhanced voice into a high-precision wake-up word detection model, carrying out wake-up word detection, and entering S70 when a wake-up word is detected, and otherwise, returning to S20, and S70, continuously enhancing the voicedetected by the wake-up word, then sending the enhanced voice to a recognition end and carrying out recognition. According to the speech enhancement method provided by the invention, the calculationoverhead can be effectively reduced, and the recognition task can be accurately carried out even in a strong noise scene. The method is suitable for being applied to a local end with complex environment and limited computing resources.

The invention provides a time-space array differential electromagnetic prospecting method comprising the following steps: (1) carrying out multi-time-window synchronous array data acquisition at multiple measuring points in a space and a distant reference point; (2) constructing a measuring point signal spatial-temporal data matrix X, a natural electromagnetic field signal spatial-temporal data matrix Xr and a related noise field signal spatial-temporal data matrix Y according to observation data; (3) decomposing Xr to solve a natural electromagnetic field source polarization parameter Alpha, decomposing Y to solve a related noise field source polarization parameter Beta, and solving the space modulus U of each measuring point relative to a natural field source and the space modulus V of each measuring point relative to a related noise field source based on Alpha, Beta and X; and (4) working out the natural field tensor impedance and the related noise field tensor impedance of each measuring point based on U and V. According to the invention, the mode of data acquisition is flexible, noise is allowed to exist in all measuring channels and time windows, signal-noise separation is realized according to the features of field source signals, and the natural field tensor impedance and the related noise field tensor impedance of all the measuring points can be obtained through one processing.

The invention belongs to the field of airplane vibration and noise, and relates to an engine noise test technology. The engine noise test technology comprises measuring point optimization arrangement, multichannel data simultaneous acquisition and cloud method data post processing. The measuring point optimization arrangement enables important noise information of an engine noise field to be captured by use of quite few microphones; the multichannel data simultaneous acquisition ensures the accuracy of acquisition data; and the cloud method data post processing can enable the noise distribution of a tail jet flow field to be obtained more visually. The engine noise test technology has the following advantages: the test precision is high, the test result is visual, the multichannel simultaneous acquisition reduces the frequency of starting an engine during testing, and the test cost is saved.

The invention discloses a double layer ring microphone array voice enhancement method. Different beam forming methods are used according different sound field environments so that the noise robustnessof the microphone array can be enhanced. When the sound field environment is the scattering noise field, the method of combination of first-order and second-order differential beam former items is used at different bands to perform voice enhancement and the high directivity factor can be acquired without sacrificing the white noise gain.

The invention discloses an acoustic vector sensor amplitude weight MUSIC direction finding method, belongs to the sensor signal processing technical field, and specifically relates to a method that uses a single acoustic vector sensor to carry out target direction finding in a sea environment noise field; the method is realized via an acoustic vector sensor; the acoustic vector sensor comprises asound pressure sensor and three vibration velocity sensor in a space common point mode, and can simultaneously measure the sound pressure and three vibration velocity components in x, y and z directions. The method combines to consider target angle and sound pressure channel and vibration velocity channel ambient noise powers, compensates the sound pressure and vibration velocity channel ambient noise power non-consistency, thus ensuring high estimation precision and resolution under a low signal to noise ratio condition; the method can solve the problems that an existing MUSIC direction finding technology is high in sidelobe and fat in main lobe, and cannot distinguish two targets in the sea environment noise field; the method can be applied to solve the passive direction finding problemsof a weak target and dual-target in the sea environment noise field.

According to the invention, the surrounding noise distribution and change features of all points are collected so as to simulate and build a whole noise sound field model shown in the description, wherein the noise field sound model is a group of continuous functions in a three-dimensional space and comprises the sound features of each frequency. The method comprises the steps: calculating the coefficients of basis functions of the noise sound field model; constructing a model of one noise reduction sound model according to the current controller parameters, carrying out the preliminary noisereduction with the noise sound field, and then calculating the energy of the whole space according to the collected noise sound field model. The coefficients of basis functions of the noise sound field model are combined for designing the controller parameters under the condition that the overall energy is minimum, and then the sound field model counteracting the noise sound field is constructed according to the model, so as to achieve the precise noise reduction, thereby enabling the noise reduction effect of the system to be optimal. In other words, the method achieves the noise reduction ata position that the noise reduction is most required, so as to achieve the optimal noise reduction effect of the whole space, and reduce the noise level of the space.

The invention relates to a laboratory playback device and method of an actual noise field. The front end of the laboratory playback device is respectively connected with a computer and a horn; a computer sends noise through the horn or the noise is acquired and then sent to a processing component in the computer for carrying out calibration, test and the like. The laboratory playback device and method solve the defects that noise is not definite in directivity and enough in scattering property, is static and insufficient in coverage surface and the like in the past. According to the invention, noise playback can effectively cover the actual noise field of a communication terminal using environment from a point noise source with definite directivity to nondirectional scattering noise, thereby providing a noise environment with effective, objective and accurate communication terminal denoising performance measurement, ensuring that playback of the laboratory noise field is accurately consistent with that of the actual noise filed, accurately measuring the denoising performance of the communication terminal and ensuring accurate, effective and objective results.

The invention provides a test system of measuring engine air inlet noise sound power and a method thereof. In the invention, assembling of an installation support and a sound intensity probe is specially designed. The test system is constructed, and a scientific sound intensity and sound power algorithm is used to process a test signal. Through using a characteristic that a sound intensity vector carries out integral along a closed curved surface, an engine air inlet noise is completely isolated and extracted from an integral and complex noise field of an engine mathematically so as to be served as a reliable basis of evaluating the engine air inlet noise. Compared to sound power measurement by using an existing traditional sound pressure method, by using the method in the invention, a test result is irrelevant with a peripheral sound field, which means that there is no requirement to a sound field test environment and the test does not need to be performed in a specific acoustic environment, such as an anechoic chamber and a live room. Based on a mathematics principle, a characteristic of an air inlet noise source can be extracted from the complex engine noise field. Tool equipment, such as a big barrier board, an air inlet extension tube and the like, does not need to be designed and made.

The invention particularly relates to a method for background noise removal by an electromagnetic measuring technology. The method belongs to the technical field of the electromagnetic environment detection and comprises synchronously performing electromagnetic radiation field intensity detection on different detection points along the same direction of radiation source through a detection system which is formed by three same detecting devices; measuring comprehensive field intensity of electromagnetic radiation field intensity and noise field intensity; utilizing a data processing program of the detection system to obtain noise field intensity; and calculating electromagnetic radiation field intensity after noise is eliminated. Accordingly, the method for the background noise removal by the electromagnetic measuring technology has the advantages of enabling measuring results to be accurate and guaranteeing accurate and reliable electromagnetic radiation environmental assessments.