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314 results about "Head-related transfer function" patented technology

A head-related transfer function (HRTF) also sometimes known as the anatomical transfer function (ATF) is a response that characterizes how an ear receives a sound from a point in space. As sound strikes the listener, the size and shape of the head, ears, ear canal, density of the head, size and shape of nasal and oral cavities, all transform the sound and affect how it is perceived, boosting some frequencies and attenuating others. Generally speaking, the HRTF boosts frequencies from 2–5 kHz with a primary resonance of +17 dB at 2,700 Hz. But the response curve is more complex than a single bump, affects a broad frequency spectrum, and varies significantly from person to person.

Binaural synthesis, head-related transfer functions, and uses thereof

PCT No. PCT / DK95 / 00089 Sec. 371 Date Dec. 27, 1996 Sec. 102(e) Date Dec. 27, 1996 PCT Filed Feb. 27, 1995 PCT Pub. No. WO95 / 23493 PCT Pub. Date Aug. 31, 1995A method and apparatus for simulating the transmission of sound from sound sources to the ear canals of a listener encompasses novel head-related transfer functions (HTFs), novel methods of measuring and processing HTFs, and novel methods of changing or maintaining the directions of the sound sources as perceived by the listener. The measurement methods enable the measurement and construction of HTFs for which the time domain descriptions are surprisingly short, and for which the differences between listeners are surprisingly small. The novel HTFs can be exploited in any application concerning the simulation of sound transmission, measurement, simulation, or reproduction. The invention is particularly advantageous in the field of binaural synthesis, specifically, the creation, by means of two sound sources, of the perception in the listener of listening to sound generated by a multichannel sound system. It is also particularly useful in the designing of electronic filters used, for example, in virtual reality systems, and in the designing of an "artificial head" having HTFs that approximate the HTFs of the invention as closely as possible in order to make the best possible representation of humans by the artificial head, thereby making artificial head recordings of optimal quality.
Owner:M O SLASHED LLER HENRIK +3

Apparatus and method of reproducing virtual sound

An apparatus and method of reproducing a 2-channel virtual sound while dynamically controlling a sweet spot and crosstalk cancellation are disclosed. The method includes: receiving broadband signals, setting compensation filter coefficients according to response characteristics of bands and setting stereophonic transfer functions according to spectrum analysis; down mixing an input multi-channel signal into two channel signals by adding head related transfer functions (HRTFs) measured in a near-field and a far-field to the input multi-channel signal, canceling crosstalk of the down mixed signals on the basis of compensation filter coefficients calculated using the set stereophonic transfer functions, and compensating levels and phases of the crosstalk cancelled signals on the basis of the set compensation filter coefficients for each of the bands.
Owner:SAMSUNG ELECTRONICS CO LTD

Positional audio rendering

An audio rendering system and method are disclosed. The audio rendering system generally comprises front and rear signal modifiers configured to receive a plurality of audio signals representing a plurality of sources of aural information and location information representing apparent location for the source of said aural information. A gain is applied to the signals representative of the location information. A front signal modifier includes a plurality of head-related transfer functions filters and a rear signal modifier includes a plurality of filters configured to approximate head-related transfer function filters. The system further includes front speakers comprising a left front speaker and right front speaker configured to receive signals from the front signal modifier and generate a signal to a listener. At least one rear speaker is configured to receive signals from the rear signal modifier and generate a signal to the listener to offset frontward bias created by the front speakers. The gains applied to the signal are calculated to produce generally equal perceived energy from each of the front and rear speakers.
Owner:AUREAL SEMICONDUCTOR +1

Signal Generation for Binaural Signals

A device for generating a binaural signal based on a multi-channel signal representing a plurality of channels and intended for reproduction by a speaker configuration having a virtual sound source position associated to each channel, is described. It includes a correlation reducer for differently processing, and thereby reducing a correlation between, at least one of a left and a right channel of the plurality of channels, a front and a rear channel of the plurality of channels, and a center and a non-center channel of the plurality of channels, in order to obtain an inter-similarity reduced set of channels; a plurality of directional filters, a first mixer for mixing outputs of the directional filters modeling the acoustic transmission to the first ear canal of the listener, and a second mixer for mixing outputs of the directional filters modeling the acoustic transmission to the second ear canal of the listener. According to another aspect, a center level reduction for forming the downmix for a room processor is performed. According to even another aspect, an inter-similarity decreasing set of head-related transfer functions is formed.
Owner:FRAUNHOFER GESELLSCHAFT ZUR FOERDERUNG DER ANGEWANDTEN FORSCHUNG EV

Binaural multi-channel decoder in the context of non-energy conserving upmix rules

ActiveUS20070280485A1Reducing and eliminating energy-errorEasy to useSpeech analysisCode conversionVocal tractComputer science
A multi-channel decoder for generating a binaural signal from a downmix signal using upmix rule information on an energy-error introducing upmix rule for calculating a gain factor based on the upmix rule information and characteristics of head related transfer function based filters corresponding to upmix channels. The one or more gain factors are used by a filter processor for filtering the downmix signal so that an energy corrected binaural signal having a left binaural channel and a right binaural channel is obtained.
Owner:DOLBY INT AB

Decoding of binaural audio signals

InactiveUS20070160218A1Increased exploitationImproving efficiency in transmittingSpeech analysisStereophonic systemsSound imageSide information
A method for synthesizing a binaural audio signal, the method comprising: inputting a parametrically encoded audio signal comprising at least one combined signal of a plurality of audio channels and one or more corresponding sets of side information describing a multi-channel sound image; and applying a predetermined set of head-related transfer function filters to the at least one combined signal in proportion determined by the corresponding set of side information to synthesize a binaural audio signal. A corresponding parametric audio decoder, parametric audio encoder, computer program product, and apparatus for synthesizing a binaural audio signal are also described.
Owner:NOKIA CORP

Dynamic Decoding of Binaural Audio Signals

Inputting of a parametrically encoded audio signal comprising at least one combined signal of a plurality of audio channels and one or more corresponding sets of side information describing a multi-channel sound image and including channel configuration information is shown along with deriving, from the channel configuration information, audio source location data describing at least one of horizontal and vertical positions of audio sources in the binaural audio signal; selecting, from a predetermined set of head-related transfer function filters, a left-right pair of head-related transfer function filters matching closest to the audio source location data, wherein the left-right pair of head-related transfer function filters is searched in a stepwise motion in a horizontal plane; and synthesizing a binaural audio signal from the at least one processed signal according to side information and the channel configuration information.
Owner:NOKIA TECHNOLOGLES OY

Estimation of head-related transfer functions for spatial sound representative

The estimation of an HRTF for a given individual is accomplished by means of a coupled model, which identifies the dependencies between one or more images of readily observable characteristics of an individual, and the HRTF that is applicable to that individual. Since the HRTF is highly influenced by the shape of the listener's outer ear, as well as the shape of the listener's head, images of a listener which provides this type of information are preferably applied as an input to the coupled model. In addition, dimensional measurements of the listener can be applied to the model. In return, the model provides an estimate of the HRTF for the observed characteristics of the listener.
Owner:INTERVAL RESEARCH CORPORATION

Binaural rendering using subband filters

Transfer functions like Head Related Transfer Functions (HRTF) needed for binaural rendering are implemented efficiently by a subband-domain filter structure. In one implementation, amplitude, fractional-sample delay and phase-correction filters are arranged in cascade with one another and applied to subband signals that represent spectral content of an audio signal in frequency subbands. Other filter structures are also disclosed. These filter structures may be used advantageously in a variety of signal processing applications. A few examples of audio applications include signal bandwidth compression, loudness equalization, room acoustics correction and assisted listening for individuals with hearing impairments.
Owner:DOLBY LAB LICENSING CORP

Perceptual synthesis of auditory scenes

An auditory scene is synthesized by applying two or more different sets of one or more spatial parameters (e.g., an inter-ear level difference (ILD), inter-ear time difference (ITD), and / or head-related transfer function (HRTF)) to two or more different frequency bands of a combined audio signal, where each different frequency band is treated as if it corresponded to a single audio source in the auditory scene. In one embodiment, the combined audio signal corresponds to the combination of two or more different source signals, where each different frequency band corresponds to a region of the combined audio signal in which one of the source signals dominates the others. In this embodiment, the different sets of spatial parameters are applied to synthesize an auditory scene comprising the different source signals. In another embodiment, the combined audio signal corresponds to the combination of the left and right audio signals of a binaural signal corresponding to an input auditory scene. In this embodiment, the different sets of spatial parameters are applied to reconstruct the input auditory scene. In either case, transmission bandwidth requirements are reduced by reducing to one the number of different audio signals that need to be transmitted to a receiver configured to synthesize / reconstruct the auditory scene.
Owner:AVAGO TECH INT SALES PTE LTD

Statistical analysis of potential audio system configurations

A system is provided for configuring an audio system for a given space. The system may statistically analyze potential configurations of the audio system to configure the audio system. The potential configurations may include positions of the loudspeakers, numbers of loudspeakers, types of loudspeakers, listening positions, correction factors, or any combination thereof. The statistical analysis may indicate at least one metric of the potential configuration including indicating consistency of predicted transfer functions, flatness of the predicted transfer functions, differences in overall sound pressure level from seat to seat for the predicted transfer functions, efficiency of the predicted transfer functions, or the output of predicted transfer functions. The system also provides a methodology for selecting loudspeaker locations, the number of loudspeakers, the types of loudspeakers, correction factors, listening positions, or a combination of these schemes in an audio system that has a single listening position or multiple listening positions.
Owner:HARMAN INT IND INC

Decoding of binaural audio signals

A method for synthesizing a binaural audio signal, the method comprising: inputting a parametrically encoded audio signal comprising at least one combined signal of a plurality of audio channels and one or more corresponding sets of side information describing a multi-channel sound image; and applying a predetermined set of head-related transfer function filters to the at least one combined signal in proportion determined by said corresponding set of side information to synthesize a binaural audio signal.
Owner:NOKIA CORP

Apparatus and method of reproducing a 7.1 channel sound

A method and an apparatus to reproduce a 7.1 channel encoded sound through a 5.1 channel speaker system are provided. The apparatus includes a decoder to separate a 7.1 channel audio bitstream into 8 channel audio signals, a signal corrector to correct characteristics of a left channel audio signal, a right channel audio signal, a center channel audio signal, left and right surround channel audio signals, and a low frequency effect channel audio signal out of the 8 channel audio signals, a back surround filter to form virtual speakers for a left back channel audio signal and a right back channel audio signal at arbitrary locations using head related transfer functions measured at predetermined locations around a listener and to cancel crosstalk between the virtual speakers, and an adder to add the right surround channel audio signal output by the signal corrector to the right back channel audio signal output by the back surround filter and to add the left surround channel audio signal output by the signal corrector to the left back channel audio signal output by the back surround filter.
Owner:SAMSUNG ELECTRONICS CO LTD

Virtual surround for headphones and earbuds headphone externalization system

ActiveUS20120201405A1Intensity difference is increasedHeadphones for stereophonic communicationSpeech analysisHead sizeHeadphones
A combination of techniques for modifying sound provided to headphones to simulate a surround-sound speaker environment with listener adjustments. In one embodiment, Head Related Transfer Functions (HRTFs) are grouped into multiple groups, with four types of HRTF filters or other perceptual models being used and selectable by a user. Alternately, a custom filter or perceptual model can be generated from measurements of the user's body, such as optical or acoustic measurements of the user's head, shoulders and pinna. Also, the user can select a speaker type, as well as other adjustments, such as head size and amount of wall reflections.
Owner:LOGITECH EURO SA

Vehicle alarm sound outputting device and program

In a vehicle alarm sound output device and a program, position data of an obstacle(s) and sound data of an alarm sound are output from an obstacle detector to DSP of a virtual sound source generator. Position data of a tire having air pressure abnormality and sound data of an alarm sound are output from an abnormality detector to DSP. Position data of a target object of a route guidance and sound data of a voice are output from a position detector to DSP. In DSP, an audio signal with which a virtual sound source can be implemented is created by using a detection signal / localization position converting table and head related transfer functions, and the audio signal thus created is output to a sound output unit. In the sound output unit, the signal corresponding to the audio signal is output to speakers so that a passenger(s) can hear an alarm sound such as a warning sound, a voice guidance or the like from the localization position of a virtual sound source.
Owner:DENSO CORP

Surround sound virtualizer and method with dynamic range compression

Method and system for generating output signals for reproduction by two physical speakers in response to input audio signals indicative of sound from multiple source locations including at least two rear locations. Typically, the input signals are indicative of sound from three front locations and two rear locations (left and right surround sources). A virtualizer generates left and right surround outputs useful for driving front loudspeakers to emit sound that a listener perceives as emitting from rear sources. Typically, the virtualizer generates left and right surround outputs by transforming rear source inputs in accordance with a head-related transfer function. To ensure that virtual channels are well heard in the presence of other channels, the virtualizer performs dynamic range compression on rear source inputs. The dynamic range compression is preferably accomplished by amplifying rear source inputs or partially processed versions thereof in a nonlinear way relative to front source inputs.
Owner:DOLBY LAB LICENSING CORP

Room impulse response

Audio loudspeaker and headphone virtualizers and methods use room impulse responses with modified individual head-related transfer functions prior to superposition including middle truncation; and perform convolutions in the frequency domain with zero-padded sections to avoid circular convolution overlap.
Owner:TEXAS INSTR INC

Dynamic hearing protection method and device

A dynamic hearing protection method and device with which a hearing protection device specific differential head related transfer function corresponding to the difference between an open ear resonance measurement of the user's ear canal or an ear canal approximating the user's ear canal without the hearing protection device being worn in the ear canal and an open ear resonance measurement with the hearing protection device being worn in the ear canal as a function of the angle of sound incidence is determined and when using the hearing protection device, a frequency-dependent gain function to the captured audio signals selected according to the presently determined angle of sound incidence with each of the gain functions is determined by inverting the previously determined HPD specific differential HRTF for the respective sound incidence angle, to compensate for the effect of the presence of the hearing protection device on the open ear resonance.
Owner:PHONAK

Front surround system and method of reproducing sound using psychoacoustic models

A front surround reproduction system improving the stereo effect of mid and low frequency signals by using a psychoacoustic model, and a method thereof. An audio reproducing system to reproduce multi-channel audio signals by using a plurality of speakers includes a split unit to copy the input multi-channel signals and to split the signals into two groups of multi-channel signals, a virtual sound processing unit to generate a virtual sound signal based on a head related transfer function (HRTF) from the one group of the multi-channel signals split in the split unit, a beam forming processing unit to generate a sound beam signal by adjusting the delays and levels of the multi-channel signals belonging to the other group split in the split unit, and a crossover network unit to adjust the characteristics of the virtual sound signal and the sound beam signal generated in the virtual sound processing unit and the beam forming processing unit, respectively, and to provide the virtual sound signal and the sound beam signal to mid and low frequency speaker arrays and high frequency speaker arrays, respectively.
Owner:SAMSUNG ELECTRONICS CO LTD

Head-related transfer function convolution method and head-related transfer function convolution device

A head-related transfer function (HRTF) convolution method arranged, when an audio signal is reproduced acoustically by an electro-acoustic conversion unit disposed in a nearby position of both ears of a listener, to convolute an HRTF into the audio signal, which allows the listener to listen to the audio signal such that a sound image is localized in a perceived virtual sound image localization position, the method including the steps of: measuring, when a sound source is disposed in the virtual sound image localization position, and a sound-collecting unit is disposed in the position of the electro-acoustic conversion unit, a direct-wave direction HRTF regarding the direction of a direct wave, and reflected-wave direction HRTFs regarding the directions of selected one or more reflected waves, from the sound source to the sound-collecting unit, separately beforehand; and convoluting the obtained direct-wave direction HRTF, and the reflected-wave direction HRTFs into the audio signal.
Owner:SONY CORP

Sound tuning method

The invention relates to a method for automated tuning of a sound system, the sound system comprising delay lines, equalizing filters, and at least two loudspeakers, the method comprising the steps of reproducing a useful sound signal through the loudspeakers, measuring sound pressure values at least one location, providing a target transfer function for tuning the delay lines and the equalizing filters of the sound system, the target transfer function representing a desired transfer characteristics of the sound system, adjusting the delay of the delay lines, and adjusting amplitude responses of the equalizing filters such, that the actual transfer characteristics of the sound system approximates the target function.
Owner:HARMAN BECKER AUTOMOTIVE SYST

Head-related transfer function measurement method, head-related transfer function convolution method, and head-related transfer function convolution device

A head-related transfer function measurement method includes the steps of: first measuring, including placing an acousto-electric conversion unit nearby both ears of a listener where placement of an electro-acoustic conversion unit is assumed, picking up sound waves emitted at a perceived sound source position with the acousto-electric conversion unit in a state with a dummy head or a human at the listener position, and measuring a head-related transfer function from only the sound waves directly reaching the acousto-electric conversion unit; second measuring, including picking up sound waves emitted at a perceived sound source position with the acousto-electric conversion unit, with no dummy head or human at the listener position, and measuring a natural-state transfer property from only the sound waves directly reaching the acousto-electric conversion unit; normalizing the head-related transfer function with the natural-state transfer property to obtain a normalized head-related transfer function; which is stored in a storage unit.
Owner:SONY CORP

Audio device

A dummy listener and right and left speakers 13 and 14 are disposed in an anechoic room as a model of the layout of those a car cabin 15 or the like. Transfer functions ALL, ALR, ARL and ARR in a space ranging from the speakers 13 and 14 to the right and left ears of a listener 16 in a car cabin 15 or the like are calculated from impulse response series aLL(t) to aRR(t) obtained when pulse sounds are respectively emitted from the speakers 13 and 14. A correction circuit 10b contains correction transfer functions H11, H12, H21 and H22, which are obtained by an inverse matrix of a 2-row and 2-column regular matrix of which the elements are the transfer functions ALL, ALR, ARL and ARR. Audio signals SL and SR on which head related transfer functions are superimposed are applied to the correction circuit 10b, and the output signals of the correction circuit 10b are supplied to the speakers 13 and 14.
Owner:PIONEER CORP

Method and apparatus for producing spatialized audio signals

InactiveUS6961439B2Augment spatial filteringIncreases awareness and desireTwo-channel systemsLoudspeaker spatial/constructional arrangementsSound sourcesVirtual position
A method and apparatus for producing virtual sound sources that are externally perceived and positioned at any orientation in azimuth and elevation from a listener is described. In this system, a set of speakers is mounted in a location near the temple of a listener's head, such for example, on an eyeglass frame or inside a helmet, rather than in earphones. A head tracking system determines the location and orientation of the listener's head and provides the measurements to a computer which processes audio signals, from a audio source, in conjunction with a head related transfer function (HRTF) filter to produce spatialized audio. The HRTF filter maintains the virtual location of the audio signals / sound, thus allowing the listener to change locations and head orientation without degradation of the audio signal. The audio system of the present invention produces virtual sound sources that are externally perceived and positioned at any desired orientation in azimuth and elevation from the listener.
Owner:THE UNITED STATES OF AMERICA AS REPRESENTED BY THE SECRETARY OF THE NAVY

Virtual 3D replaying method based on earphone

The invention relates to a virtual 3D replaying method based on an earphone. The method comprises the following steps: setting a parameter of a virtual 3D sound source; calculating an absorption value of air to sound and calculating a sound pressure attenuation factor of the sound; calculating a room pulse response (RIR); calculating a position distance d between each sample point of the RIR and a receiving point, calculating a sound pressure of the original sound source after being transmitted for the d distance according to the d; using a interpolation method to process an absorption coefficient of a metope frequency point so as to obtain the RIR after increasing air attenuation and metope absorption; calculating a level angle and an elevation angle between a sound source point position and a head position so as to select a proximal head correlation transmission function; carrying out convolution on head-related transfer function (HRTF) and the RIR after increasing the air attenuation and the metope absorption so as to acquire binaural room pulse response (BRIR); carrying out the convolution on the BRIR and an input sound signal so as to realize a virtual 3D sound signal based on the earphone. By using the method provided in the invention, an '' inner head '' problem during earphone replaying, a distance direction feeling problem, a room characteristic problem and the like can be solved so as to realize a virtual 3D effect based on the earphone.
Owner:INST OF ACOUSTICS CHINESE ACAD OF SCI +1

Headphones for 3d sound

Headsets (20, 50, 60, 71) provide surround sound and full 3 dimensional effects to a user to simulate the effects of direction and sound source. Advantages include: surround sound effect without the limitations of Head-Related Transfer Functions, and pinna effect customized to each user's ears; horn shape tube outlets (32) to create an efficient transmission of sound; ability to space the headset speakers (22, 24) away from the user's ear and to maintain sound quality by addition of a chamber (28) behind the speakers (22, 24), with the aid of tube sound guides (23, 25) and the horn shaped outlets; and, no need for electronic hardware to process the electrical signals to create desired effects as placement of the speakers creates the correct timing, and damping material (34) in the tubes between speakers creates a desired intensity drop. Head tracking capability is also provided.
Owner:HILDEBRANDT JAMES G

Methods of using head related transfer function (HRTF) enhancement for improved vertical- polar localization in spatial audio systems

A method of enhancing vertical polar localization of a head related transfer function (HRTF). The method includes splitting an audio signal and generating left and right output signal by enhancing a left lateral magnitude of the respective signal by determining a log lateral component of the respective frequency-dependent audio gain that is equal to a median log frequency-dependent audio gain for all audio signals of that channel having an desired one of the plurality of perceived source locations. A vertical magnitude of the respective audio signal is enhanced by determining a log vertical component of the respective frequency-dependent audio gain that is equal to a product of a first enhancement factor and a difference between the respective frequency-dependent audio gain at the desired one of the plurality of perceived source locations and the lateral magnitude of respective audio signal. The output signals are time delayed according to an interaural time and delivered to left and right ears of a listener.
Owner:THE UNITED STATES OF AMERICA AS REPRESETNED BY THE SEC OF THE AIR FORCE

Channel estimation for OFDM systems

In a method for channel estimation of an OFDM signal transmitted via a channel, an initial channel transfer function is calculated by channel estimation. A channel impulse response is calculated on the basis of the initial channel transfer function. Values of the channel impulse response or of a filtered channel impulse response are classified as noise or as a signal as a function of the level of the values of the channel impulse or of the level of the values of the filtered channel impulse response. A noise-reduced channel impulse response is calculated on the basis of the channel impulse response using the classification, and a noise-reduced channel transfer function is calculated on the basis of this noise-reduced channel impulse response.
Owner:INTEL CORP
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