CN112218224A

CN112218224A - HRTF (head-mounted HRTF) measuring method and device based on head-mounted loudspeaker system

Info

Publication number: CN112218224A
Application number: CN202010984194.9A
Authority: CN
Inventors: 杈逛豢; 边仿
Original assignee: Hifiman Tianjin Technology Co ltd
Current assignee: Kunshan Haifeiman Technology Group Co ltd
Priority date: 2020-09-18
Filing date: 2020-09-18
Publication date: 2021-01-12
Anticipated expiration: 2040-09-18
Also published as: CN112218224B

Abstract

The invention provides an HRTF measuring method based on a head-mounted loudspeaker system and measuring equipment thereof. The method comprises the following steps of: processing the sound source signal into a test signal according to a preset HRTF; converting the test signal into a test sound signal by a head-mounted loudspeaker and playing the test sound signal to a listener; receiving the test sound signal by a sound receiving device arranged at the ear of the listener to generate a measurement signal; processing the measurement signal by a processing device to generate a measurement HRTF; and comparing the measured HRTF with a preset HRTF to obtain a comparison characteristic quantity, comparing the comparison characteristic quantity with a threshold value, and obtaining the personalized HRTF of the listener when the comparison characteristic quantity is smaller than the threshold value. The invention aims at the head-related transfer function difference caused by the difference of the head-mounted loudspeaker and the free-field loudspeaker system on the transmission path, and realizes the head-related transfer function measurement when a listener wears the head-mounted loudspeaker system.

Description

HRTF (head-mounted HRTF) measuring method and device based on head-mounted loudspeaker system

Technical Field

The invention relates to the technical field of audio analysis and processing, in particular to an HRTF measuring method based on a head-mounted loudspeaker system and measuring equipment thereof.

Background

A Head-Related Transfer Function (HRTF), also known as atf (acoustic Transfer Function), is an audio localization algorithm describing the transmission process of sound waves from a sound source to two ears of a listener, which reflects the comprehensive filtering result of the sound waves by human body structures, such as Head, pinna, trunk structures and even sexes, and contains localization information about the sound source, and has very important significance for the reproduction of stereo sound effects and the simulation of virtual position information of the sound source. The sound source device mainly comprises an Interaural Time Difference (ITD) and an Interaural sound pressure Level Difference (ILD), and in a practical application scene, a loudspeaker can convert signals processed by HRTFs into sound wave signals to show different spatial hearing effects.

The HRTF has personalized characteristics, and different physiological structures and size characteristics of different listeners determine that the HRTF has unique HRTF characteristics. The method is characterized in that 52 subjects are measured by professor of Nemada fungus, namely institute of physical science and technology acoustics of university of south China's science and technology institute in head-related transfer function database and characteristic analysis thereof, a high spatial resolution HRTF based on Chinese collected samples is established, and research results show that the largest ITDS has obvious gender difference in statistical significance; and the comparison with a foreign CIPIC HRTF database shows that the ITDS based on the Chinese sample has significant difference with the statistical result mainly based on the Western sample, namely the personalized features of the HRTFs have obvious gender and population difference.

The existing HRTF model which is applied to the application is an averaged HRTF model based on sample statistics, particularly based on the statistical result of a western person sample, the HRTF model cannot really accord with the HRTF characteristics of an actual listener, and therefore a reproduced sound field or a simulated sound field established based on the HRTF model cannot accurately reflect sound source position information in the sound field.

Furthermore, the way listeners acquire sound from a head mounted speaker system is different from a free field speaker system. For a free-field loudspeaker system, sound waves emitted by a sound source are scattered by the head, auricle, trunk and the like of a listener and then reach the ears, any body structure contacted by the sound waves in the process changes the sound waves, and the frequency and the phase of the sound waves are different; for a head-mounted speaker system, the speakers are placed directly at or near the ear orifices of the listener's ear, and the sound waves emitted from the sound source do not pass through the torso of the listener. Compared with a free field loudspeaker system, the influence of the trunk of a listener on sound waves emitted by the head-mounted loudspeaker system is small, so how to research the influence of the head-mounted loudspeaker system on the judgment of sound source position information of the listener, namely the acquisition of the personalized head-related transfer function of the listener when using the head-mounted loudspeaker system, becomes a key for improving the stereo listening effect of the head-mounted loudspeaker system.

Disclosure of Invention

In view of the above disadvantages in the prior art, the present invention provides an HRTF measuring method based on a head mounted speaker system, which specifically includes:

step S110: and processing the sound source signal into a test signal according to a preset HRTF.

Step S120: the test signal is converted into a test sound signal by the head-mounted loudspeaker and played to a listener.

Step S130: the test acoustic signal is received by a sound receiving device arranged at the ear of the listener to generate a measurement signal.

Step S140: the measurement signal is processed by a processing device to generate a measurement HRTF.

Step S150: comparing the measured HRTF with a preset HRTF to obtain a comparison characteristic quantity, comparing the comparison characteristic quantity with a threshold value, if the comparison characteristic quantity is larger than the threshold value, repeating the steps S110 to S140, and processing the measured HRTF generated in the previous step S140 as the preset HRTF and the sound source signal into a test signal.

And if the comparison characteristic quantity is smaller than a threshold value, taking the measured HRTF as the personalized HRTF of the listener.

Preferably, the comparison feature amount includes an ITD feature amount and an ILD feature amount; the ITD characteristic quantity is the ITD difference rate of the measured HRTF and the preset HRTF, and the ILD characteristic quantity is the ILD difference rate of the measured HRTF and the preset HRTF; the threshold values include an ITD feature quantity threshold value and an ILD feature quantity threshold value.

Preferably, the ITD threshold is 10% and the ILD threshold is 2%.

Preferably, the measuring method further comprises a reciprocity checking step of interchanging the positions of the speaker and the sound receiving device in steps S120 and S130, measuring and calculating to obtain a reciprocity HRTF, and cross-checking the reciprocity HRTF with the personalized HRTF.

Preferably, the measuring method further comprises an ear profile measuring step including: an optical measuring element disposed inside the head-mounted speaker is used to acquire a contour image of the listener's ear by optical mapping means and output the contour image to a processing device.

Preferably, the processing device identifies the contour image and parameterizes the contour image to obtain the ear contour parameters of the listener.

Preferably, the processing device constructs a database by using the contour image and the ear contour parameters as indexes, and stores the personalized HRTF as target data in the corresponding ear contour parameter index.

Preferably, the average value of the personalized HRTFs in the database is taken as the preset HRTF.

Preferably, the processing device compares the ear contour parameters of the listener to be tested with the database, and selects the personalized HRTF corresponding to the index closest to the listener as the preset HRTF.

The invention also provides HRTF measuring equipment based on the head-mounted loudspeaker system, which comprises:

the synthesis unit is used for processing the sound source signal into a test signal according to a preset HRTF; a head mounted speaker for playing the test signal from the head mounted speaker to a listener; the sound receiving device is arranged at the ear of the listener and used for receiving the test sound signal and generating a measurement signal according to the test sound signal; the analysis unit is used for processing the measurement signal and generating a measurement HRTF; a comparing unit, configured to compare the measured HRTF with a preset HRTF to obtain a comparison feature quantity, compare the comparison feature quantity with a threshold value, repeat steps S110 to S140 if the comparison feature quantity is greater than the threshold value, and process the measured HRTF generated in the previous step S140 as the preset HRTF and the sound source signal to a test signal; if the comparison characteristic quantity is smaller than a threshold value, taking the measured HRTF as an individualized HRTF of a listener; the synthesis unit, the analysis unit and the comparison unit form processing equipment; the head-mounted loudspeaker is tightly attached to the face of a listener, and the base noise in the space formed by the head-mounted loudspeaker and the face of the listener is not more than 10 decibels.

Preferably, the head mounted speaker comprises an outer shell and an elastic ear cap; the outer shell is connected with the elastic ear muffs, and the elastic ear muffs are used for being in contact with the heads of listeners; the shell body is different from one side of the elastic earmuff is provided with a multi-layer net structure, the grids of the multi-layer net structure are arranged in a staggered mode, and grid resonant cavities are arranged on the grids.

Preferably, the grid overlapping area of two adjacent layers of grids between the multiple layers of the net structures is not more than 20%.

Preferably, the elastic ear cap comprises an elastic layer and a sound insulation ring, and the elastic layer wraps the outer side of the sound insulation ring; one end of the sound insulation ring is connected with the outer shell, and one side of the sound insulation ring, which is different from the outer shell, is wrapped by the elastic layer; when the head-mounted loudspeaker is worn, the distance between the head of a listener and the sound insulation ring is not more than 0.8 mm; the sound insulation ring is a closed ring with double-layer shells, a vacuum layer is arranged between the double-layer shells, and the thickness of each layer of shell of each double-layer shell is not less than 1.6 mm.

Preferably, the double-layer shell comprises an inner shell and an outer shell, a ring resonant cavity is arranged on the outer shell, and the ring resonant cavity is an axisymmetric hole structure with the diameter of 0.02 mm to 0.12 mm and the depth of 0.1 mm to 0.35 mm; the ring resonant cavities are uniformly distributed on the outer shell, and the aperture ratio of the ring resonant cavities is 50-90%.

Preferably, the head mounted speaker further comprises an optical measurement device, the processing device further comprises an image processing unit and an image parameter processing unit, the optical measurement device is used for acquiring an ear contour image of the listener and outputting the ear contour image to the processing device; the processing equipment carries out parameterization processing on the ear contour image through the image processing unit to obtain ear contour parameters, and an individualized HRTF database which is indexed based on the ear contour parameters is constructed through the image parameter processing unit according to the ear contour image, the ear contour parameters and the individualized HRTFs corresponding to the ear contour images.

The invention aims at the head-related transfer function difference caused by the difference of a head-mounted loudspeaker and a free-field loudspeaker system on a transfer path, and can obtain the head-related transfer function which is in line with the body characteristics of a user, particularly when the head-mounted loudspeaker is used, by using the HRTF measuring method and the measuring equipment thereof based on the head-mounted loudspeaker system, more real HRTF data can be provided for the design and the use of the head-mounted loudspeaker system, and better stereo sound effect can be provided for the application of a head-mounted earphone in scenes of movies, games and far-field sound effect music quality identification.

Drawings

Fig. 1 is a flowchart of an HRTF measurement method based on a head mounted speaker system according to an embodiment of the present invention.

Fig. 2 is a schematic diagram of an HRTF measuring apparatus based on a head mounted speaker system according to an embodiment of the present invention.

Fig. 3 is a schematic partial structure diagram of a head mounted speaker according to an embodiment of the invention.

Fig. 4 is a partial structure diagram of an elastic earcap according to an embodiment of the present invention.

Fig. 5 is a schematic view of a sound isolation ring structure according to an embodiment of the present invention.

Fig. 6 is a schematic diagram of a mesh structure according to an embodiment of the present invention.

FIG. 7 is a schematic cross-sectional view of a resonant cavity according to an embodiment of the present invention.

Wherein, the head-mounted loudspeaker-110, the outer shell-111, the net structure-1111, the grid resonant cavity-1112, the elastic ear cap-112, the elastic layer-1121, the sound insulation ring-1122, the inner shell-11221, the outer shell-11222, the ring resonant cavity-11223, the sound receiving device-120, the processing device-130, the synthesizing unit-131, the analyzing unit-132 and the comparing unit-133; sound source signal-20, test signal-21, test sound signal-22 and measurement signal-23; personalized HRTF-30, preset HRTF-31 and measurement HRTF-32.

Detailed Description

In order to obtain personalized HRTF data of a listener wearing a head-mounted speaker and establish a personalized HRTF database based on the ear contour characteristics of the listener, the HRTF measuring method based on the head-mounted speaker system and the measuring equipment thereof are realized by the following technical scheme:

example 1:

referring to fig. 1, fig. 1 is a flowchart illustrating an HRTF measuring method based on a head mounted speaker system according to an embodiment of the invention.

The embodiment provides an HRTF measuring method based on a head-mounted speaker system, the measuring method is performed by a measuring device based on the head-mounted speaker system, and the measuring method comprises the following steps: step S110: processing the sound source signal 20 into a test signal 21 according to a preset HRTF 31; step S120: converting the test signal 21 into a test sound signal 22 by the head mounted speaker 110 to be played to a listener; step S130: receiving the test acoustic signal 22 by a sound receiving device 120 arranged at the ear of the listener to generate a measurement signal 23; step S140: processing the measurement signal 23 by the processing device 130 to generate a measurement HRTF 32; step S150: comparing the measured HRTF32 with a preset HRTF31 to obtain a comparison characteristic quantity, comparing the comparison characteristic quantity with a threshold value, repeating the steps S110 to S140 if the comparison characteristic quantity is greater than the threshold value, and processing the measured HRTF32 generated in the previous step S140 as a preset HRTF31 and the sound source signal 20 as a test signal 21; if the comparison characteristic quantity is smaller than the threshold value, the measured HRTF32 is used as the personalized HRTF30 of the listener.

In the above process, the comparison feature quantity may include ITD feature quantity and ILD feature quantity, which are an ITD difference rate and an ILD difference rate of the measured HRTF32 and the preset HRTF31, respectively, corresponding to an ITD threshold value and an ILD threshold value, respectively. Specifically, the ITD threshold is set to 10%, and the ILD threshold is set to 2%.

In particular, a speaker array may also be arranged within the head mounted speaker.

The embodiment aims at the head-related transfer function difference caused by the difference of a head-mounted loudspeaker and a free-field loudspeaker system on a transfer path, can obtain the head-related transfer function which is in line with the physical characteristics of a user, particularly when the head-mounted loudspeaker is used, can provide more real HRTF data for the design and the use of the head-mounted loudspeaker system, and provides better stereophonic sound effect for the application of a head-mounted earphone in scenes of movies, games and far-field sound effect and musical identification.

Example 2:

the embodiment provides an HRTF measuring method based on a head-mounted speaker system, which further comprises a reciprocity verifying step, wherein positions of the speaker and the sound receiving device in the steps S120 and S130 are interchanged, and the steps S210 to S250 are executed to obtain a reciprocity HRTF, so as to perform cross verification with the personalized HRTF. Wherein, step S210: processing the sound source signal 20 into a test signal 21 according to a preset HRTF 31; step S220: the test signal 21 is played to the head-wearing type radio device through a loudspeaker; step S230: receiving a test sound signal 22 by a microphone arranged in the head-mounted sound receiving device to generate a measurement signal 23; step S240: processing the measurement signal 23 by the processing device 130 to generate a measurement HRTF 32; step S250: comparing the measured HRTF32 with a preset HRTF31 to obtain a comparison characteristic quantity, comparing the comparison characteristic quantity with a threshold value, repeating the steps S210 to S240 if the comparison characteristic quantity is greater than the threshold value, and processing the measured HRTF32 generated in the previous step S240 as the preset HRTF and the sound source signal 20 into a test signal 21; if the comparison characteristic quantity is smaller than the threshold value, the measured HRTF32 is used as a reciprocal HRTF.

In this embodiment, the personalized HRTF30 obtained in step S150 is verified by using a reciprocity method. The method comprises the steps of arranging a loudspeaker at the position of the ear canal mouth of a listener, replacing the head-mounted loudspeaker with a head-mounted radio device to solve a reciprocal HRTF of an inverse path, comparing the reciprocal HRTF with the personalized HRTF30 obtained in the process from the step S110 to the step S150, and repeating the step S110 to the step S150 if the difference between the reciprocal HRTF and the personalized HRTF30 is larger than an expectation until the difference between the personalized HRTF30 and the reciprocal HRTF is smaller than the expectation.

Specifically, the above-mentioned differences include ITD differences and ILD differences. Where the expected value for the ITD difference is 10% and the expected value for the ILD difference is 2%.

More specifically, in order to ensure the consistency of the reverse path, the head-mounted sound receiving device and the head-mounted loudspeaker have a systematic external structure, and the arrangement position of the microphone of the head-mounted sound receiving device and the arrangement position of the loudspeaker of the head-mounted loudspeaker are consistent; and, the difference between the signal-to-noise ratio of the measurement signal of the reciprocity checking step and the signal-to-noise ratio of the measurement signal obtained in the process from the step S110 to the step S150 is not more than 5%.

In particular, in the reciprocity checking step, the listener should wear an in-ear protection device, such as an in-ear earplug, to prevent noise from the near-ear sound source from physiologically affecting the listener during the test.

More particularly, the speaker may be arranged at a side of the in-ear guard other than the side contacting the ear canal of the listener to acquire the test signal 21 from the processing device 130 by wireless communication means.

In this embodiment, according to the helmholtz reciprocity principle, the positions of the speaker and the microphone are exchanged, the personalized HRTF30 obtained in the process from step S110 to step S150 is verified by a reciprocity method, and within the allowable range of the difference of the sound transmission paths, the personalized HRTF obtained by the forward path is checked again, so that the measurement accuracy is improved.

Example 3:

the embodiment provides an HRTF measuring method based on a head-mounted loudspeaker system, which further comprises an ear contour measuring step, wherein an optical measuring element arranged inside the head-mounted loudspeaker is used for acquiring a contour image of the ear of a listener by adopting an optical mapping method, the contour image is output to a processing device, and an image processing unit of the processing device identifies the contour image and carries out parameterization processing on the contour image to obtain the ear contour parameters of the listener. The ear contour parameters can include the area ratio of the earlobe to the auricle, the distance between two feet of the antihelix crus, the depth and the area of a triangular fossa, the thickness of two rounds, the height and the width of the upper edge of the tragus and the lower edge of the antihelix, the length and the depth of a cymba concha, the depth of a concha cavity, the height difference and the projection overlapping rate between the antihelix and the concha cavity, the height difference and the projection overlapping rate of the ear tragus of the ear canal speaking, the shape parameters of the ear canal opening and the like.

In this embodiment, the processing device further uses the contour image and the ear contour parameter as indexes through the image parameter processing unit to construct a database, and the database stores the personalized HRTF obtained in the testing process as target data under the corresponding ear contour parameter index for subsequent retrieval and retrieval.

In particular, in the measurement process, the average value of the personalized HRTFs stored in the database can be used as a preset HRTF; or the individualized HRTF corresponding to the ear contour parameter index closest to the current listener is selected as the preset HRTF by comparing the ear contour parameters of the current listener to be tested in the database through the processing equipment.

In particular, the database also includes an index of the gender and age of the listener.

In particular, the optical mapping means may be laser imaging or infrared imaging means, the ear profile image may be a three-dimensional image, and the optical measuring elements may be arranged in a single point, a double point, a three point or an array.

The embodiment provides an HRTF measuring method based on a head-mounted loudspeaker system, which is characterized in that ear contour information of a listener is obtained through an optical mapping method, and an individualized HRTF database related to the ear contour of a human body is constructed according to the ear contour information and the individualized HRTF obtained through measurement, so that the parameterized relationship between the ear structure of the human body and the HRTF can be studied more deeply, a better solution of an initial HRTF can be obtained in the measuring process better, the measuring process of the HRTF can be shortened, and the measuring accuracy of the HRTF can be improved.

Example 4:

referring to fig. 2 to 7, fig. 2 is a schematic diagram of an HRTF measuring apparatus based on a head mounted speaker system according to an embodiment of the present invention; FIG. 3 is a schematic diagram of a partial structure of a head mounted speaker according to an embodiment of the present invention; FIG. 4 is a schematic view of a partial structure of an elastic earcap according to an embodiment of the present invention; FIG. 5 is a schematic view of a sound isolation ring structure according to an embodiment of the present invention; FIG. 6 is a schematic diagram of a web structure according to an embodiment of the present invention; FIG. 7 is a schematic cross-sectional view of a resonant cavity according to an embodiment of the present invention.

The present embodiment provides an HRTF measuring apparatus based on a head-mounted speaker system, which is capable of constructing a background environment conforming to an HRTF testing process and completing HRTF measurement. The measuring apparatus includes: a synthesizing unit 131, configured to process the sound source signal into a test signal according to a preset HRTF; a head mounted speaker for playing the test signal from the head mounted speaker to a listener; the sound receiving device is arranged at the ear of the listener and used for receiving the test sound signal and generating a measurement signal according to the test sound signal; an analyzing unit 132, configured to process the measurement signal and generate a measurement HRTF; a comparing unit 133, configured to compare the measured HRTF with a preset HRTF to obtain a comparison feature quantity, compare the comparison feature quantity with a threshold value, repeat steps S110 to S140 if the comparison feature quantity is greater than the threshold value, and process the measured HRTF generated in the previous step S140 as the preset HRTF and the sound source signal as a test signal; and if the comparison characteristic quantity is smaller than a threshold value, taking the measured HRTF as the personalized HRTF of the listener.

In order to enable the sound receiving device 120 to have a better sound receiving effect and prevent the influence of the external environment on the test process, the head-mounted speaker 110 is tightly attached to the face of the listener, the noise of a base in a space formed by the head-mounted speaker 110 and the face of the listener is not more than 10 decibels, and the signal-to-noise ratio of the measuring equipment is not less than 78 decibels.

In particular, the head mounted speaker 110 includes an outer shell 111 and an elastic ear cap 112, the elastic ear cap 112 is used for contacting with the head of the listener, and the other side is connected with the outer shell 111; one side of the outer shell 111, which is different from the elastic ear cap 112, is provided with a multi-layer mesh structure 1111, the meshes of the multi-layer mesh structure 1111 are arranged in a staggered manner, the mesh resonant cavities 1112 are arranged on the meshes, the resonant cavities on each layer of the mesh structure 1111 have different size characteristics, the mesh overlapping area of two adjacent layers of meshes between the multi-layer mesh structures 1111 is not more than 20%, so that the outer shell 111 has a good resistance noise elimination effect on external low-frequency noise within a wider frequency band range.

The elastic ear cap 112 includes an elastic layer 1121 and a sound-proof ring 1122, and the elastic layer 1121 wraps the outside of the sound-proof ring 1122. One end of the sound-proof ring 1122 is connected with the outer shell 111, and one end of the sound-proof ring 1122 different from the outer shell 111 is wrapped by the elastic layer 1121; when the head mounted speaker 110 is worn, the distance between the head of the listener and the sound-proof ring 1122 is not more than 0.8 mm, so that the transmission path of external noise through the structural components of the head mounted speaker 110 is reduced while the wearing comfort is ensured.

The soundproof ring 1122 is a closed ring having double shells with a vacuum layer therebetween, and the thickness of each shell of the double shells is not less than 1.6 mm. The double-layer shell comprises an inner shell 11221 and an outer shell 11222, a ring resonant cavity 11223 is arranged on the outer shell 11222, and the ring resonant cavity 11223 is of an axisymmetric hole structure with the diameter of 0.02 mm to 0.12 mm and the depth of 0.1 mm to 0.35 mm; the ring resonant cavities 11223 are uniformly distributed in the outer shell 11222, the aperture ratio of the ring resonant cavities 11223 is 50% to 90%, external noise is further isolated, particularly a transmission path of low-frequency noise input through the elastic ear loops 112, and the sound insulation ring 1122 enables the elastic ear loops 112 to achieve a sound attenuation effect of 48 db on low-frequency noise of 10 to 200 hz.

The embodiment realizes personalized HRTF30 measurement when a user wears a head-mounted speaker through a set of measuring equipment based on a head-mounted speaker system; optimize the design of making an uproar passively fall of head mounted speaker simultaneously, head mounted speaker closely laminates with the listener head when wearing, fuses multiple high porosity resonant cavity, sound absorbing material and transfer path separation overall arrangement, compromises the noise elimination and the isolated processing of different frequency low frequency noise and high frequency noise for the head mounted speaker is not more than 10 decibels with the base noise in the confined space that the listener head formed when using, and measuring equipment's SNR is not less than 78 decibels.

It should be noted that the above-mentioned embodiments are provided for further detailed description of the present invention, and the present invention is not limited to the above-mentioned embodiments, and those skilled in the art can make various modifications and variations on the above-mentioned embodiments without departing from the scope of the present invention.

Claims

1. A HRTF measuring method based on a head-mounted loudspeaker system is characterized by comprising the following steps:

step S110: processing the sound source signal into a test signal according to a preset HRTF;

step S120: converting the test signal into a test sound signal by a head-mounted loudspeaker and playing the test sound signal to a listener;

step S130: receiving the test sound signal by a sound receiving device arranged at the ear of the listener to generate a measurement signal;

step S140: processing the measurement signal by a processing device to generate a measurement HRTF;

step S150: comparing the measured HRTF with a preset HRTF to obtain a comparison characteristic quantity, comparing the comparison characteristic quantity with a threshold value, if the comparison characteristic quantity is greater than the threshold value, repeating the steps S110 to S140, and processing the measured HRTF generated in the previous step S140 as the preset HRTF and the sound source signal into a test signal;

2. The HRTF measuring method according to claim 1, wherein the comparison feature includes an ITD feature and an ILD feature; the ITD characteristic quantity is the ITD difference rate of the measured HRTF and the preset HRTF, and the ILD characteristic quantity is the ILD difference rate of the measured HRTF and the preset HRTF; the threshold values include an ITD feature quantity threshold value and an ILD feature quantity threshold value.

3. The HRTF measurement method of claim 2, wherein the ITD threshold is 10% and the ILD threshold is 2%.

4. The HRTF measuring method according to claim 1, wherein the HRTF measuring method further comprises a reciprocity checking step, wherein positions of the speaker and the sound receiving device in steps S120 and S130 are exchanged, and a reciprocal HRTF is obtained through measurement and calculation and cross-checked with the personalized HRTF.

5. The HRTF measuring method based on the head-mounted loudspeaker system, according to claim 1, wherein the measuring method further comprises an ear shape measuring step, comprising: an optical measuring element disposed inside the head-mounted speaker is used to acquire a contour image of the listener's ear by optical mapping means and output the contour image to a processing device.

6. The HRTF measuring method based on a head-mounted speaker system according to claim 5, wherein the processing device identifies the contour image and parameterizes the contour image to obtain the ear contour parameters of the listener.

7. The HRTF measuring method based on a head-mounted speaker system according to claim 6, wherein the processing device constructs a database with the contour image and the ear contour parameters as indexes, and stores the personalized HRTFs as target data under the corresponding ear contour parameter indexes.

8. The HRTF measuring method according to claim 7, wherein an average value of the personalized HRTFs in the database is used as a preset HRTF.

9. The HRTF measuring method of claim 7, wherein the processing device compares the ear contour parameters of the listener to be tested with the database, and selects the personalized HRTF corresponding to the index closest to the listener as the preset HRTF.

10. An HRTF measuring device based on a head mounted speaker system, comprising:

the synthesis unit is used for processing the sound source signal into a test signal according to a preset HRTF;

a head mounted speaker for playing the test signal from the head mounted speaker to a listener;

the sound receiving device is arranged at the ear of the listener and used for receiving the test sound signal and generating a measurement signal according to the test sound signal;

the analysis unit is used for processing the measurement signal and generating a measurement HRTF;

a comparing unit, configured to compare the measured HRTF with a preset HRTF to obtain a comparison feature quantity, compare the comparison feature quantity with a threshold value, repeat steps S110 to S140 if the comparison feature quantity is greater than the threshold value, and process the measured HRTF generated in the previous step S140 as the preset HRTF and the sound source signal to a test signal; if the comparison characteristic quantity is smaller than a threshold value, taking the measured HRTF as an individualized HRTF of a listener;

the synthesis unit, the analysis unit and the comparison unit form processing equipment;

the head-mounted loudspeaker is tightly attached to the face of a listener, and the base noise in the space formed by the head-mounted loudspeaker and the face of the listener is not more than 10 decibels.

11. A HRTF measuring device based on a head-mounted loudspeaker system according to claim 10, wherein the head-mounted loudspeaker comprises an outer casing and an elastic ear cap; the outer shell is connected with the elastic ear muffs, and the elastic ear muffs are used for being in contact with the heads of listeners; the shell body is different from one side of the elastic earmuff is provided with a multi-layer net structure, the grids of the multi-layer net structure are arranged in a staggered mode, and grid resonant cavities are arranged on the grids.

12. An HRTF measuring device based on a head-mounted loudspeaker system, according to claim 11, wherein the mesh overlapping area of two adjacent layers of mesh between the mesh structures is not more than 20%.

13. The HRTF measuring device of claim 11, wherein the elastic earmuffs comprise an elastic layer and a sound-proof ring, the elastic layer wrapping around an outer side of the sound-proof ring; one end of the sound insulation ring is connected with the outer shell, and one side of the sound insulation ring, which is different from the outer shell, is wrapped by the elastic layer; when the head-mounted loudspeaker is worn, the distance between the head of a listener and the sound insulation ring is not more than 0.8 mm; the sound insulation ring is a closed ring with double-layer shells, a vacuum layer is arranged between the double-layer shells, and the thickness of each layer of shell of each double-layer shell is not less than 1.6 mm.

14. The HRTF measuring device based on a head-mounted speaker system according to claim 13, wherein the double-layered casing comprises an inner casing and an outer casing, the outer casing is provided with a ring resonant cavity, and the ring resonant cavity is an axisymmetric hole structure with a diameter of 0.02 mm to 0.12 mm and a depth of 0.1 mm to 0.35 mm; the ring resonant cavities are uniformly distributed on the outer shell, and the aperture ratio of the ring resonant cavities is 50-90%.

15. A HRTF measuring device based on a head mounted loudspeaker system according to claim 10, wherein the head mounted loudspeaker further comprises an optical measuring device, the processing device further comprises an image processing unit and an image parameter processing unit; the optical measurement device is used for acquiring an ear contour image of a listener and outputting the ear contour image to the processing device; the processing equipment carries out parameterization processing on the ear contour image through the image processing unit to obtain ear contour parameters, and an individualized HRTF database which is indexed based on the ear contour parameters is constructed through the image parameter processing unit according to the ear contour image, the ear contour parameters and the individualized HRTFs corresponding to the ear contour images.