Generation of personalized head-related transfer function (PHRTFS)

Abstract

A method for efficiently generating a personalized head-related transfer function, pHRTF, for a user of a media playback device includes obtaining a default HRTF associated with one or more default parameters, each default parameter associated with a particular human body feature, determining at least one personalization parameter, and generating a personalized head-related transfer function, pHRTF, for a user of the media playback device. Each personalization parameter is associated with one of the particular human body characteristics of the user, and modifying the default HRTF based on a relationship between the at least one personalization parameter and the corresponding one or more default parameters to determine the pHRTF.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Provisional Patent Application No. 63 / 446,774 filed on February 17, 2023 and U.S. Provisional Patent Application No. 63 / 613,318 filed on December 21, 2023, which are incorporated herein by reference in their entirety. Technical Field

[0003] The present invention relates to the generation of head-related transfer functions (HRTFs). Background Art

[0004] Head-related transfer functions (HRTFs) are a set of functions that describe how the human ear receives sound from a sound source at different arrival directions. These functions typically describe a linear filtering process that reflects the acoustic effects of the ear, head, and torso on incoming sound waves.

[0005] HRTFs can be defined in a variety of ways, including as time-domain impulse responses or frequency-domain responses. HRTFs are typically grouped in pairs, providing responses for each ear. HRTF filter pairs can be used to provide the listener with an experience that simulates the sound (at each ear) that would occur if an audio signal were presented from a specific direction of arrival. Different HRTF filter pairs create the illusion of different sound source directions.

[0006] Due to the diffraction and obstruction of incident sound waves on the user's body, the user's anatomical structure may affect the way the user's ears receive sound. Therefore, it is often desirable to customize the HRTF for a specific individual. Such HRTF is referred to herein as personalized HRTF (pHRTF). Summary of the Invention

[0007] Although pHRTF can be obtained through experimental measurement or modeled using personalized information related to users, this is often a complex and time-consuming process.

[0008] It is an object of the present invention to facilitate the generation of pHRTF.

[0009] According to a first aspect of the invention, this and other objects are achieved by a method for generating a set of personalized head-related transfer functions pHRTF for a user of a media playback device, the method comprising obtaining a default HRTF set associated with one or several default parameters, each default parameter being associated with a specific human body feature, determining at least one personalized parameter, each personalized parameter being associated with one of the specific human body features of the user, and modifying the default HRTF set based on the relationship between the at least one personalized parameter and the corresponding one or more default parameters to determine the pHRTF set.

[0010] Modifications to the default HRTF set may include, for example, frequency remapping, frequency scaling, and angle shifting.

[0011] The present invention provides an effective way to modify and personalize HRTFs based on some well-defined parameters. By determining the default parameters of the default HRTF set and comparing these parameters with the personalized parameters specific to the user, the default HRTF set can be modified according to a predetermined relationship.

[0012] The default parameters may be physical parameters, such as head size, ear size, and ear tilt angle. However, at least one of the default parameters may be associated with a specific non-physical feature, wherein the default parameters include a default value, and wherein modifying the default HRTF set includes adjusting the default HRTF to compensate for a difference between the value determined to correspond to the specific non-physical feature of the user and the default value.

[0013] A default HRTF set can be selected from a plurality of such sets based on one or more personalization parameters associated with non-physical characteristics of the user. Such non-physical characteristics can be demographic attributes such as age, gender, sex at birth, geographic location, nationality, and race. By selecting an appropriate default HRTF set, the personalization process can be made more robust and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The present invention will now be described in more detail with reference to the accompanying drawings, which show currently preferred embodiments of the invention.

[0015] Figure 1 A user wearing headphones is shown.

[0016] Figure 2 is a schematic diagram illustrating a Cartesian coordinate system according to some embodiments.

[0017] Figure 3 is a schematic diagram illustrating sound incident on the left ear of a subject according to some embodiments.

[0018] Figure 4 is a schematic diagram illustrating determining an HRTF from an HRTF library according to some embodiments.

[0019] Figure 5 is a schematic diagram illustrating modification of a starting HRTF library to form a new HRTF library according to some embodiments.

[0020] Figure 6 is a schematic diagram showing details of the direction of incident waves reaching the ear according to some embodiments.

[0021] Figure 7is a schematic diagram showing details of the direction of an incident wave arriving at a rotating ear according to some embodiments.

[0022] Figure 8 is a schematic diagram illustrating size variations between ears according to some embodiments.

[0023] Figure 9 is a graph illustrating the frequency response of an HRTF according to some embodiments.

[0024] Figure 10 is a graph illustrating interaural time delay between left and right ear HRTFs according to some embodiments.

[0025] Figure 11 is a schematic diagram illustrating a modification of a delay-separated HRTF filter according to some embodiments.

[0026] Figure 12 is a flow chart illustrating a process for generating a personalized HRTF using an electronic device according to some embodiments. DETAILED DESCRIPTION

[0027] refer to Figure 1 , user 1 uses a pair of headphones 3 to listen to audio played from a media player 2. For binaural rendering of the audio, a head-related transfer function (HRTF) is used.

[0028] This article describes techniques for processing a library of HRTFs to generate a new library of HRTFs tailored to an individual listener. The adapted HRTFs are referred to as personalized HRTFs, or pHRTFs. In the following description, for purposes of explanation, numerous examples and specific details are set forth in order to provide a thorough understanding of the present disclosure.

[0029] The systems and methods disclosed in this application can be implemented as software, firmware, hardware, or a combination thereof. In hardware implementations, the division of tasks does not necessarily correspond to the division of physical units; on the contrary, a physical component can have multiple functions, and a task can be performed by several physical components in cooperation.

[0030] The computer hardware may be, for example, a server computer, a client computer, a personal computer (PC), a tablet PC, a set-top box (STB), a personal digital assistant (PDA), a cellular phone, a smartphone, an XR device (e.g., an AR or VR headset), a network device, a network router, a switch or a bridge, or any machine capable of executing (sequentially or otherwise) instructions that specify actions to be taken by the computer hardware. Furthermore, the present disclosure relates to any collection of computer hardware that, alone or in combination, executes instructions to perform any one or more of the concepts discussed herein.

[0031] Some or all of the components may be implemented by one or more processors that accept computer-readable (also referred to as machine-readable) code comprising an instruction set that, when executed by the one or more processors, results in the implementation of at least one of the methods described herein. Any processor that is capable of executing (sequentially or otherwise) an instruction set that specifies an action to be taken is included. Thus, an example is a typical processing system (e.g., computer hardware) that includes one or more processors. Each processor may include one or more of a CPU, a graphics processing unit, and a programmable DSP unit. The processing system may also include a storage subsystem that includes a hard drive, an SSD, RAM, and / or ROM. A bus subsystem for communication between components may be included. During execution of the software by the computer system, the software may reside in the storage subsystem and / or within the processor.

[0032] The one or more processors may operate as standalone devices or may be connected to, for example, a network to other processors. Such a network may be based on a variety of network protocols and may be the Internet, a wide area network (WAN), a local area network (LAN), or any combination thereof.

[0033] The software may be distributed on computer-readable media, which may include computer storage media (or non-transitory media) and communication media (or transient media). As known to those skilled in the art, the term "computer storage media" includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information such as computer-readable instructions, data structures, program modules or other data. Computer storage media include, but are not limited to, various forms of physical (non-transitory) storage media, such as EEPROM, flash memory or other storage technology, CD-ROM, digital versatile disk (DVD) or other optical disk storage, cassettes, magnetic tape, disk storage or other magnetic storage devices, or any other medium that can be used to store the required information and can be accessed by a computer. In addition, as known to those skilled in the art, (transitory) communication media typically contain computer-readable instructions, data structures, program modules or other data in a modulated data signal such as a carrier wave or other transmission mechanism, and include any information transfer medium.

[0034] Head-related transfer function (HRTF) filters can be used to process audio signals to produce binaural audio signals, thereby providing the listener with the illusion that sounds are arriving from a specified direction of arrival. The direction of arrival can be defined by a (x, y, z) unit vector (where Figure 2 Cartesian coordinates are defined in ). According to Figure 2, the coordinate frame is positioned with its origin approximately at the center of the listener's head, with the X-axis 101 pointing forward (in the direction of the listener's nose), the Y-axis 102 pointing to the listener's left, and the Z-axis 103 pointing upward through the top of the listener's head.

[0035] In one embodiment, the arrival direction of a sound source may be defined according to a side polar coordinate system, whereby the angle (φ, θ) refers to the lateral angle φ (the angle with the mid-plane xz) and the elevation angle θ (the angle measured as a rotation about the interaural y-axis).

[0036] The relationship between the (x, y, z) unit vector (in Cartesian coordinates) and the side polar angle is as follows:

[0037]

[0038] Figure 3 1 shows a sound emitted by an object 5 and incident on the left ear 4 of the user 1 from a direction 6. The elevation angle θ defines the angular displacement of the direction 120 relative to the forward-facing X-axis 101 as the angle around the Y-axis ( Figure 2 102) in the rotation.

[0039] HRTF filters are defined as frequency responses according to the following nomenclature:

[0040]

[0041] where the frequency response is a complex value (indicated by magnitude and phase);

[0042]

[0043] Alternatively, the nomenclature can be simplified to refer to various groups of related HRTFs. For example:

[0044]

[0045] In another example of nomenclature, the id hyperscript can be used to define various groups of HRTFs with specific characteristics using descriptive IDs, e.g.

[0046]

[0047] In some embodiments, the HRTF filters for the left and right ears include a time delay difference (interaural time difference, or ITD).

[0048] In some embodiments, each left / right pair (eg, corresponding to a left / right pair) in a HRTF group (eg, a HRTF set) is processed as follows: and ) can be modified to form a delayed separated HRTF (e.g., by the function and express):

[0049] Determine the time delay associated with each HRTF filter:

[0050]

[0051] The new delay-separated filter responses are determined by removing the corresponding time delay from each HRTF response:

[0052]

[0053] Determine the interaural time delay (ITD) between left / right pairs:

[0054]

[0055] Data representing one or more HRTFs (e.g., an HRTF group or HRTF set) can be stored or transmitted by various means known in the art. For example, an HRTF set may include HRTF filters corresponding to a finite number of directions of arrival. In some embodiments, various interpolation methods known in the art are used to calculate HRTF filters corresponding to arbitrary directions based on a finite number of DOAs.

[0056] An HRTF library may refer to a representation of one or more HRTF sets, including left and right ear HRTF filters and corresponding directions of arrival. In some embodiments, the HRTF library includes N delayed separated HRTFs:

[0057]

[0058] Where N is typically 8 or greater, typically between 32 and 1024. Higher values ​​of N will provide a more accurate representation of the HRTF set (e.g., higher directional resolution). An HRTF library consisting of a smaller set of responses (say, N < 30) will provide a less accurate representation of the HRTF set.

[0059] In some embodiments, the directions of arrival in the HRTF library correspond to unit vectors that are uniformly distributed on the surface of a unit sphere (e.g., the angular spacing between the unit vectors is approximately equal). In some embodiments, the directions of arrival in the HRTF library correspond to unit vectors that are uniformly distributed on (e.g., intersecting) a portion of the surface of a unit sphere (e.g., a region of the surface of the unit sphere whose surface area is less than the entire unit sphere). In some embodiments, the HRTF library includes DOAs corresponding to a fixed range of elevation and / or lateral angles (e.g., rotation angles relative to the median plane) on the unit sphere.

[0060] Figure 44. A process 400 is shown by which a left / right HRTF filter pair 406 corresponding to an arrival direction (φ, θ) 402 is determined from an HRTF library 401. An interpolation process 403 forms interpolated delayed separated HRTFs 404 corresponding to the arrival direction (φ, θ) 402 from the HRTF library 401. The delayed separated HRTFs 404 are processed 405 to form a left / right HRTF filter pair 406.

[0061] Given a smooth function f(φ,θ) sampled in several (N) unit vector directions (f(φ n ,θ n ):n∈1..N), the estimated value of the function value (f′(φ,θ)) in any direction can be estimated by using a linear mixture of the sampled values.

[0062]

[0063] In some embodiments, the gain value is selected according to the interpolation method: g n

[0064] Define the target vector

[0065]

[0066] Define the sampling vector

[0067]

[0068] The gain value is chosen such that: for all n∈1..N, And g n >0, and the error vector The amplitude is the smallest.

[0069] According to some embodiments, the interpolation gain (g n (φ,θ)), such as vector basis amplitude translation.

[0070] like Figure 4 As shown, from the HRTF library 401 (e.g., specified according to Equation 6 above), for any arrival direction (φ, θ), g is first selected according to an interpolation method such as the method defined above. n (φ,θ) is then processed 403 according to the following equation to estimate the interpolated delayed separated HRTF 404:

[0071]

[0072] The interpolated delayed separated HRTF 404 is then used to form an interpolated HRTF filter 406 according to the following equation:

[0073]

[0074] Binaural signals created using HRTF sets may be intended to provide listeners with the impression that sound objects are spatially located at different positions around them. However, a particular binaural signal may provide a more realistic spatial impression for some listeners and a less realistic spatial impression for other listeners.

[0075] When two listeners have similar physical and / or non-physical characteristics, including their head size, ear size, and the angle or pitch of their ears, the HRTF library preferred by the first listener is likely to also be preferred by the second listener.

[0076] In some embodiments, as Figure 5 As shown, a starter HRTF library 501 associated with a specific anatomical feature (Starter Feature) is first obtained, which is preferred by the listener and has a set of default parameters. Then, in a processing unit 502, the starter HRTF set 51 is modified to form a set of personalized HRTFs, pHRTFs, also called target HRTF library 401, which is suitable for a target subject with different anatomical features (target features). The modification in the processing unit 502 is based on the relationship between the default parameters and a set of personalized parameters associated with the anatomical features 510 of the target subject.

[0077] Personalized parameters can be determined from one or more images of the target / user. Techniques for deriving model parameters from features in an image are discussed in a co-pending application entitled "GENERATION OF PERSONALIZEDHEAD-RELATED TRANSFER FUNCTIONS (PHRTFS)" (Serial No.: Not Yet Assigned; Reference No.: D22129), which is incorporated herein by reference.

[0078] In other embodiments, personalization parameters may also be determined based on non-physical characteristics. For example, the target subject's age, gender, sex at birth, geographic location, nationality, race, or other demographic attributes may be used to infer (e.g., using numerical and / or machine learning-based methods) that a physical feature may have a certain size or form. As a specific example, the target subject's age may be used to infer that the target subject's head size is different from a default head size (e.g., the target subject's head size is smaller or larger than the default head size).

[0079] Figure 6 Detailed view of sound incident on the ear 4 of a user at an elevation angle θ relative to the forward X-axis 101, the user having Figure 5The listener's ear 4 is associated with a line A indicating the tilt angle of the ear 4.

[0080] Figure 7 A similar view is shown for sound incident on the user's ear 4' at an elevation angle θ relative to the forward X-axis 101, where the user has Figure 4 The target anatomical features of the target HRTF library 401 are compatible with the target HRTF library 401. The listener's ear 4' is associated with a line A' indicating the tilt angle of the ear 4'. Figure 6 The angular difference α between the ear 4 of the target listener and the ear 4′ of the target subject is referred to herein as the tilt angle α (associated with the left ear of the target listener). L or α (associated with the target listener's right ear) R .

[0081] So, given a starting HRTF library:

[0082]

[0083] According to some embodiments, a HRTF library may be defined, wherein the elevation angles in the library are suitable for compensating for the tilt angle α of the left ear of the target subject. L and the tilt angle α of the target object's right ear R :

[0084]

[0085] In another preferred embodiment, when the tilt angles associated with both ears are the same (α L =α R ), you can choose to define the target HRTF library according to the following formula:

[0086]

[0087] Figure 8 The user's ear 4 is shown at an ear height h, and the user has Figure 5 The alternative ears 104 and 204 having ear heights h' and h" will respond to incident sound waves with a frequency response similar to the frequency response associated with ear 4, but scaled according to the ear height (h' or h").

[0088] Similar adjustments can be determined for any other distance metric associated with two or more feature points of the ear. For example, the size, volume, or surface area of ​​the outer ear can be the basis for similar adjustments, to name just one example.

[0089] In some embodiments, the invention is adapted to have a scaling factor β associated with the subject's left ear. L (For example, ) and a scaling factor β associated with the subject's right ear R (For example, ) can be formed as follows:

[0090]

[0091] Figure 9 Examples of left and right ear responses 11, 13 for typical HRTFs for a particular direction of arrival from a starting HRTF library are shown. Scaled left and right ear 12, 14 responses are shown for a target HRTF library associated with a target subject having smaller ears.

[0092] In some embodiments, it is suitable to have an ear tilt angle α L and α R and / or ear scaling factor β L and β R The anatomical characteristics of the listener used in the HRTF library can be formed as follows:

[0093]

[0094] It is well known that interaural time difference (ITD) varies as a function of direction of arrival. Figure 10 The variation of ITD as a function of lateral angle (φ) is shown for an elevation angle θ = 0. The ITD associated with the starting HRTF library is shown as a solid curve 15. As shown by the dashed curve 16, a target subject with a larger head will be associated with a larger ITD.

[0095] The variation in head width of different listeners is associated with the variation in the frequency response of the HRTF associated with the respective listeners. Therefore, it is suitable to have a scaling factor β associated with the head width of the target object. H (For example, ) can be formed as follows:

[0096]

[0097] Figure 11 Processing of one of N elements of a starting HRTF library is shown, where the nth element 801 may be processed by a direction change block 802, a frequency response change block 803, and / or an ITD change block 804 to produce a corresponding nth element 805 of a target HRTF library.

[0098] In some embodiments, it is suitable to have an ear tilt angle α L and α R , ear scaling factor β L and β R, and the head scaling factor β H The target HRTF library used for the anatomical characteristics of the listener can be formed as follows:

[0099]

[0100] where w(f) is a cross-fade function that is equal to 1 when f < 1 kHz and equal to 0 when f > 3 kHz, and is generally monotonically decreasing for frequencies between 1 kHz and 3 kHz.

[0101] In some embodiments, w(f) is a piecewise linear function according to the following equation:

[0102]

[0103] In some embodiments, the starting HRTF library is determined by selecting an HRTF library associated with an individual listener. In some embodiments, the starting HRTF library is determined by combining a set of HRTF libraries associated with a corresponding set of listeners. In some embodiments, the starting HRTF library suitable for forming a target HRTF library associated with listeners who are members of a particular demographic group is determined by combining a set of HRTF libraries associated with a corresponding set of listeners who are members of a particular demographic group.

[0104] In some embodiments, several starting HRTF libraries are determined to be associated with several different demographic groups, and a target HRTF library 401 for a particular target listener is formed by first selecting a starting HRTF library 501 that is associated with a demographic group that matches the demographic attributes of the target listener. Subsequently, the selected starting HRTF library 501 is modified according to the various methods described above (e.g., Equation 16) to form the target HRTF library 401.

[0105] In some embodiments, the demographic groups are determined based on attributes including gender, sex at birth, age, weight, and race.In some embodiments, the demographic groups and / or related attributes are received via user input.

[0106] In some embodiments, the HRTF is represented as a time domain impulse response (eg, h(t)), a frequency remap (eg, M target (f) = M starter (βf)) can be remapped by the corresponding time to achieve.

[0107] It will be appreciated that a set of HRTFs in discrete directions (which may constitute a library of HRTFs) forms the basis of HRTF functions as a function of frequency (or time) and direction. Conversely, as is known in the art, a library of HRTFs may be defined based on spherical harmonic filters, based on a set of spherical harmonics. In some embodiments, a starting library of HRTFs defined based on spherical harmonics may be processed to achieve rotation about the Y axis by applying a linear blend of the starting spherical harmonic filters to generate a target set of spherical harmonic filters.

[0108] In some embodiments, where the spherical harmonics are oriented such that the spherical harmonic basis functions are periodic under rotation about the Y-axis, a linear mixture of starting spherical harmonic filters to produce a target set of spherical harmonic filters can be implemented using a sparse matrix.

[0109] Figure 12 1 is a flow chart illustrating a process for generating a personalized HRTF using an electronic device according to some embodiments. Process 1200 is performed at an electronic device (e.g., computing hardware as described above). Some operations in process 1200 may optionally be combined, the order of some operations may optionally be changed, and some operations may optionally be omitted.

[0110] As described below, process 1200 provides an efficient way to generate personalized HRTFs using an electronic device. The process reduces the computational requirements for performing device personalization, which, for battery-powered devices, conserves energy and increases the time between battery charges. Furthermore, the process enables device personalization, such as pHRTF generation, to be performed on devices with limited computational power (e.g., mobile devices).

[0111] In step 1202, the electronic device obtains a default HRTF set associated with one or more default parameters, each default parameter being associated with a specific human body feature.

[0112] In step 1204 , the electronic device determines at least one personalized parameter, each personalized parameter being associated with one of the user's specific body characteristics.

[0113] In step 1206, the electronic device modifies the default HRTF set based on a relationship between the at least one personalized parameter and the corresponding one or more default parameters to determine a pHRTF set.

[0114] In some embodiments, the step of modifying the default set of HRTFs comprises one of frequency remapping, frequency scaling, and angle shifting.

[0115] In some embodiments, at least one of the specific human features is a physical feature. In some embodiments, at least one personalization parameter is determined based on a non-physical feature of the user. In some embodiments, at least one personalization parameter is determined based on the user's age. In some embodiments, at least one personalization parameter is obtained from one or more images of the user.

[0116] In some embodiments, the default parameters include a default ear tilt angle, and modifying the default set of HRTFs includes adjusting the default HRTFs to compensate for a difference between the determined user ear tilt angle and the default tilt angle.

[0117] In some embodiments, the default parameters include a default ear size, and modifying the default HRTF set includes frequency remapping the default HRTFs based on a determined relationship between the user's ear size and the default ear size. In some embodiments, the frequency remapping is based on a ratio between the determined ear size and the default ear size. In some embodiments, the default parameters include a default head size, and modifying the default HRTF set includes frequency remapping the default HRTFs based on a determined relationship between the user's head size and the default head size. In some embodiments, the frequency remapping is based on a ratio between the determined head size and the default head size. In some embodiments, modifying the default HRTFs involves a gradual transition between frequency remapping based on ear size and frequency remapping based on head size.

[0118] In some embodiments, the default parameters include a default head size, and modifying the default set of HRTFs includes time-remapping the default HRTFs based on a determined relationship between the user's head size and the default head size. In some embodiments, the frequency remapping is based on a ratio between the determined head size and the default head size.

[0119] In some embodiments, at least one default parameter is associated with a specific non-physical characteristic, the default parameter includes a default value, and modifying the default HRTF set includes adjusting the default HRTF to compensate for a difference between a value determined to correspond to the specific non-physical characteristic of the user and the default value. In some embodiments, the default parameter is associated with one or more of age, gender, sex at birth, geographic location, nationality, and race. In some embodiments, modifying the default HRTF set includes one of frequency remapping, frequency scaling, and angle shifting. In some embodiments, the default parameter includes a default age, and modifying the default HRTF set includes frequency remapping the default HRTF based on a ratio between a determined age of the user and the default age.

[0120] In some embodiments, the default HRTF set is selected from a plurality of default HRTF sets based on one or more personalization parameters associated with non-physical characteristics of the user.In some embodiments, the personalization parameters are related to demographic attributes of the user.

[0121] Unless otherwise stated, it will be apparent from the following discussion that throughout this disclosure, discussions using terms such as "process," "calculate," "calculate," "determine," "analyze," etc., refer to the actions and / or processes of computer hardware or computing systems or similar electronic computing devices to manipulate data represented as physical quantities (e.g., electronic quantities) and / or convert them into other data similarly represented as physical quantities.

[0122] It should be understood that in the above description of exemplary embodiments of the present disclosure, various features are sometimes combined in a single embodiment, figure, or description thereof for the purpose of simplifying the disclosure and aiding in understanding one or more of the various inventive aspects. However, this method of disclosure should not be interpreted as reflecting an intention that the claimed disclosure requires more features than are expressly recited in each claim. On the contrary, as reflected in the following claims, the inventive aspects lie in less than all the features of a single preceding disclosed embodiment. Therefore, the claims following the "Detailed Description" section are hereby expressly incorporated into this "Detailed Description" section, with each claim standing on its own as a separate embodiment of the present disclosure. Furthermore, as will be understood by those skilled in the art, although some embodiments described herein include some features included in other embodiments but not other features, combinations of features of different embodiments are also intended to be included within the scope of the present disclosure and to form different embodiments. For example, in the claims below, any of the claimed embodiments may be used in any combination.

[0123] In addition, some embodiments are described herein as methods or combinations of elements of methods that can be implemented by a processor of a computer system or by other means for performing the function. Therefore, a processor with instructions for performing this method or method element forms a means for performing this method or method element. It should be noted that when the method includes several elements, such as several steps, this does not imply the order of these elements unless otherwise specified. In addition, the elements of the device embodiments described herein are examples of means for performing the functions performed by the elements for the purpose of realizing the embodiments of the present disclosure. In the description provided herein, many specific details are set forth. However, it should be understood that the embodiments of the present disclosure can be implemented without these specific details. In other cases, well-known methods, structures and techniques are not shown in detail to avoid blurring the understanding of this specification.

[0124] Those skilled in the art will recognize that the present invention is by no means limited to the preferred embodiments described above. On the contrary, numerous modifications and variations are possible within the scope of the appended claims. For example, other default parameters associated with other physical or non-physical human characteristics in addition to the above parameters may be used to generate a personalized HRTF.

[0125] Various aspects of the present disclosure may be understood from the following Enumerated Example Embodiments (EEE):

[0126] EEE 1. A method for generating a personalized set of head-related transfer functions (pHRTFs) for a user of a media playback device, comprising:

[0127] - obtaining a set of default HRTFs associated with one or more default parameters, each default parameter being associated with a specific human body feature;

[0128] - determining at least one personalization parameter, each personalization parameter being associated with one of said specific anatomy characteristics of the user; and

[0129] - modifying the default HRTF set based on a relationship between the at least one personalized parameter and corresponding one or more default parameters to determine the pHRTF set.

[0130] EEE 2. The method according to EEE 1, wherein the step of modifying the default HRTF set comprises one of frequency remapping, frequency scaling, and angle shifting.

[0131] EEE 3. The method according to EEE1 or EEE2, wherein at least one of the specific human features is a physical feature.

[0132] EEE 4. The method according to EEE 3, wherein at least one personalization parameter is determined based on a non-physical characteristic of the user.

[0133] EEE 5. The method according to EEE 4, wherein at least one personalization parameter is determined based on the age of the user.

[0134] EEE 6. The method according to EEE 3, wherein at least one personalization parameter is obtained from one or several images of the user.

[0135] EEE 7. A method according to one of EEE3-EEE6, wherein the default parameters include a default ear tilt angle, and wherein modifying the default HRTF set includes adjusting the default HRTF to compensate for a difference between the determined user ear tilt angle and the default tilt angle.

[0136] EEE 8. The method according to one of EEE3-EEE6, wherein the default parameters include a default ear size, and wherein modifying the default HRTF set includes frequency remapping of the default HRTFs based on the determined relationship between the user's ear size and the default ear size. EEE 8. The method according to one of EEE3-EEE6, wherein the default parameters include a default ear size, and wherein modifying the default HRTF set includes frequency remapping of the default HRTFs based on the determined relationship between the

[0137] EEE 9. The method according to EEE 8, wherein the frequency remapping is based on a ratio between the determined ear size and the default ear size. ...

[0138] EEE 10. The method according to one of EEE3-EEE6, wherein the default parameters include a default head size, and wherein modifying the default HRTF set includes frequency remapping the default HRTFs based on the determined relationship between the user's head size and the default head size. EEE 10. The method according to one of EEE3-EEE6, wherein the default parameters include a default head size, and wherein modifying the default HRTF set includes frequency remapping the default HRTFs based on the determined relationship between the

[0139] EEE 11. The method according to EEE10, wherein the frequency remapping is based on a ratio between the determined head size and the default head size. EEE 12. The method according to EEE 12, wherein the frequency remapping is based on a ratio between the determined head size and the default head size.

[0140] EEE 12. The method according to claims 8 and 10, wherein modifying the default HRTF involves gradual changes in frequency remapping based on ear size and frequency remapping based on head size. EEE 13.

[0141] EEE 13. The method according to one of EEE3-EEE6, wherein the default parameters include a default head size, and wherein modifying the default HRTF set includes time-delay remapping the default HRTFs based on the determined relationship between the user's head size and the default head size.

[0142] EEE 14. The method according to EEE 13, wherein the frequency remapping is based on a ratio between the determined head size and the default head size. ...

[0143] EEE 15. A method according to EEE1, wherein at least one of the default parameters is associated with a specific non-physical characteristic, wherein the default parameter includes a default value, and wherein modifying the default HRTF set includes adjusting the default HRTF to compensate for a difference between the determined value corresponding to the specific non-physical characteristic of the user and the default value.

[0144] EEE 16. The method according to EEE15, wherein the default parameters are associated with one or more of age, gender, birth sex, geographic location, nationality and race.

[0145] EEE 17. The method according to EEE 15 or EEE 16, wherein the step of modifying the default HRTF set comprises one of frequency remapping, frequency scaling, and angular shifting. EEE 17.

[0146] EEE 18. The method according to EEE 15, wherein the default parameters include a default age, and wherein modifying the default set of HRTFs includes frequency remapping the default HRTFs based on a ratio between the determined user age and the default age. ...

[0147] EEE 19. The method according to any of the preceding EEEs, wherein the default HRTF set is selected from a plurality of default HRTF sets based on one or several personalized parameters associated with non-physical characteristics of the user. ...

[0148] EEE 20. The method according to EEE19, wherein the personalization parameters are related to demographic attributes of the user.

[0149] EEE 21. A system for generating a personalized set of head-related transfer functions (pHRTFs) for a user of a media playback device, the system comprising a processing unit configured to:

[0150] receiving a default HRTF set associated with one or more default parameters, each default parameter being associated with a specific human body feature,

[0151] receiving at least one personalization parameter, each personalization parameter being associated with one of the specific body characteristics of the user, and

[0152] The default HRTF set is modified based on a relationship between the at least one personalized parameter and corresponding one or more default parameters to determine the pHRTF set.

[0153] EEE 22. A computer program product comprising computer program code portions, the computer program code portions being configured to perform the method according to one of EEE1-EEE20 when executed on a computer processor. EEE 22.

[0154] EEE 23. A non-transitory computer-readable storage medium storing instructions, which, when executed by a computing device, cause the computing device to perform the method according to one of EEE1-EEE20.

Claims

1. A method for generating a personalized set of head-related transfer functions (pHRTFs) for a user of a media playback device, comprising: - obtaining a set of default HRTFs associated with one or more default parameters, each default parameter being associated with a specific human body feature; - determining at least one personalization parameter, each personalization parameter being associated with one of said specific anatomy characteristics of the user; as well as - modifying the default HRTF set based on a relationship between the at least one personalized parameter and corresponding one or more default parameters to determine the pHRTF set.

2. The method according to claim 1, wherein The step of modifying the default HRTF set includes one of frequency remapping, frequency scaling, and angle shifting.

3. The method of claim 1 or 2, wherein at least one of the specific human characteristics is a physical characteristic. The method according to claim 3 , wherein at least one personalization parameter is determined based on a non-physical characteristic of the user. The method of claim 4 , wherein at least one personalization parameter is determined based on the age of the user.

6. The method according to claim 3, wherein: At least one personalization parameter is obtained from one or several images of the user.

7. The method according to one of claims 3-6, wherein the default parameters include a default ear tilt angle, and wherein modifying the default HRTF set includes adjusting the default HRTF to compensate for a difference between the determined user ear tilt angle and the default tilt angle.

8. The method of one of claims 3-6, wherein the default parameters include a default ear size, and wherein modifying the default HRTF set includes frequency remapping of the default HRTFs based on the determined relationship between the user's ear size and the default ear size.

9. The method of claim 8, wherein the frequency remapping is based on a ratio between the determined ear size and the default ear size.

10. The method of one of claims 3-6, wherein the default parameters include a default head size, and wherein modifying the default set of HRTFs includes frequency remapping the default HRTFs based on a determined relationship between the user's head size and the default head size.

11. The method according to claim 10, wherein: The frequency remapping is based on a ratio between the determined head size and the default head size.

12. The method according to claims 8 and 10, wherein modifying the default HRTF involves gradual changes in frequency remapping based on ear size and frequency remapping based on head size.

13. The method of one of claims 3-6, wherein the default parameters include a default head size, and wherein modifying the default set of HRTFs includes time-delay remapping of the default HRTFs based on a determined relationship between the user's head size and the default head size.

14. The method according to claim 13, wherein: The frequency remapping is based on a ratio between the determined head size and the default head size.

15. A method according to claim 1, wherein at least one of the default parameters is associated with a specific non-physical characteristic, wherein the default parameters include default values, and wherein modifying the default HRTF set includes adjusting the default HRTF to compensate for a difference between the determined value corresponding to the specific non-physical characteristic of the user and the default value.

16. The method according to claim 15, wherein The default parameters are associated with one or more of age, gender, sex at birth, geographic location, nationality, and race.

17. The method according to claim 15 or 16, wherein the step of modifying the default HRTF set comprises one of frequency remapping, frequency scaling and angular shifting.

18. The method of claim 15, wherein the default parameters include a default age, and wherein modifying the set of default HRTFs includes frequency remapping the default HRTFs based on a ratio between the determined age of the user and the default age.

19. The method according to any of the preceding claims, wherein the default HRTF set is selected from a plurality of default HRTF sets based on one or several personalization parameters associated with non-physical characteristics of a user.

20. The method of claim 19, wherein the personalization parameters are related to demographic attributes of the user.

21. A system for generating a personalized set of head-related transfer functions (pHRTFs) for a user of a media playback device, the system comprising a processing unit configured to: receiving a default HRTF set associated with one or more default parameters, each default parameter being associated with a specific human body feature, receiving at least one personalization parameter, each personalization parameter being associated with one of the specific body characteristics of the user, and The default HRTF set is modified based on a relationship between the at least one personalized parameter and corresponding one or more default parameters to determine the pHRTF set.

22. A computer program product comprising computer program code portions configured to perform the method according to one of claims 1 to 20 when executed on a computer processor.

23. A non-transitory computer-readable storage medium storing instructions that, when executed by a computing device, cause the computing device to perform the method according to any one of claims 1-20.

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