JPH05115099A - Listening device by out-head locarization headphone - Google Patents

Abstract

PURPOSE:To simply perceive a sense of an out-head sound image locarization by using a storage card exclusive for a person in which person dependent out- head sound image locarization information is stored. CONSTITUTION:The person dependent out-head sound image locarization information resulting from applying convolution operation to inverse headphone impulse information and spatial impulse information is stored in a storage card 9. When the storage card 9 is loaded to a storage card container 8, a data content of the storage card 9 is stored in each memory of right ear use and left ear use convolution computing elements 3a, 4a. A digital input audio signal 1 and the person dependent out-head sound image locarization information are subject to convolution operation in the computing element 3a and the result is outputted to a right ear use phone of a headphone 7 via a right ear use D/A converter 5. Similarly, the input signal is calculated by the computing element 4a for the left ear and the result is outputted to the left ear use phone. Thus, even when the device is used for listening by lots of unspecified persons, a sense of an out-head sound image locarization is perceived accurately by using the person dependent storage card.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for an out-of-head localization headphone listening device in a terminal device for conference calls.

[0002] The present invention relates to an out-of-head localization headphone listening device that makes it possible to easily experience an out-of-head sound image localization feeling by using a personalized memory card in which individual out-of-head sound image localization information is stored.

[0003]

2. Description of the Related Art Before explaining the present invention, the principle of out-of-head sound image localization will be described below.

FIGS. 5A, 5B and 5C are explanatory views showing the principle of out-of-head sound image localization which is the basis of the present invention. Here, FIG. 5A shows an example in which the sound image position (localization) is recognized by both ears of a human from the sound source position in the real space, and FIG. 5B shows a virtual image by an electric information signal instead of the sound source. FIG. 5C shows an example in which sound waves are radiated from a speaker, which is a sound source, into the ear canal and inserted into the ear canal. FIG. 5C shows an unknown transfer function for localizing the sound source from the electrical information signal through the headphones to the outside of the head. An example of processing is shown.

It is generally said that it is the level difference and the delay time difference between the left and right ears that humans perceive the position of the sound source with both ears. To be exact, this results in a difference in the head-related transfer function from the sound source position to the eardrum as a specific location of both ears.

Now, a sound wave is propagated through the space from the signal Source (s) of the sound source, and the head-related transfer function to the entrance of the ear canal as a specific location of both ears or the entrance of a small microphone mounted on the front of the eardrum is changed to Space ( s), the transfer function of the ear canal from the headphones to the entrance of the small microphone through the ear canal to the channel (s), and the transfer function of the speaker to Peak
er (s) and the transfer function of the microphone are Mic (s), and the sound pressure level inserted into the small microphone is Pressu.
Let re (s) be the sound pressure level Pressure that is inserted into the small microphone input via spatial propagation and the ear canal from the electrical information signal I (s) of the actual sound source or speaker input
(S) is Pressure (s) = Space (s) × Source (s) = Space (s) × Speaker (s) × I (s) (1) On the other hand, the sound pressure level of the headphones Pressure
As can be seen from FIG. 5C, (s) ′ can be represented by an unknown transfer function Unknown (s), a headphone transfer function, and an ear canal response response transfer function. Therefore, Pressure (s) ′ = Unknown (s) × Headphone (s) × Carnel (s) × I (s) (2) Furthermore, the spatial transfer function Ku (s) of the spatial real sound field from the speaker to the small microphone is Ku (s) = Space (s) ) × Speaker (s) × Mic (s) (3) The headphone transfer function Thead (s) from the headphones to the small microphone set in the ear canal is: Head (s) = Headphone (s) × Mic (s) ) × Carnel (s) (4) and the transfer functions Ku (s) and Thead (s) are transfer functions that can be measured in advance. In order to perform out-of-head localization as if listening from the sound source position, it is sufficient that the pressures in Expressions (1) and (2) are the same function. Therefore, if Expression (1) and Expression (2) are equalized, Space (s) × Speaker (s) × I (s) = Unknown (s) × Headphone (s) × Carnel (s) × I (s) ………… (5) is obtained. Therefore, the unknown transfer function Unknown (s)
In consideration of the equations (3) and (4), Unknown (s) = (Space (s) × Speaker (s)) / (Headphone (s) × Carnel (s)) = Ku (s) / Thead (s) ... (6)

Therefore, the spatial transfer function Ku (s) including the actual sound field impulse response (head transfer function) of the space from the speaker input to the small microphone output, and the ear canal transfer function from the headphones to the small microphone set in the ear canal. If the headphone transfer function Thead (s) including is measured in advance and the calculation processing of the equation (6) is performed, the unknown transfer function Unk
It becomes possible to obtain known (s). further,
By performing a real-time convolution operation of a desired input sound signal on this unknown transfer function, the input sound source can be localized at an arbitrary location. Many literatures have been published on these theories, and as a famous book,
There are "spatial sound" by Brauert, Morimoto, and Goto published by Kashima Publishing. The above-mentioned technology has been published about 30 years ago and is now a well-known fact.

The above is the principle of the out-of-head sound image localization. The head related transfer function space (s) and the outer ear transfer function “carnel”
(S) largely depends on the shape of the head, the structure of the auricle, and the external auditory meatus, and thus differs from individual to individual. In addition, research to find the head-related transfer function space (s) has been actively carried out in order to realize a similar common sense of localization for an unspecified number of people, but it still includes the auricle structure. No studies have been conducted to find the ear canal transfer function “carnel (s)”. For this reason, even if an unspecified large number of people listen to one type of head-related transfer function space (s) and one type of ear canal transfer function carnel (s), they have not reached the point where a similar localization feeling is required. Therefore, the unknown transfer function unknown (s) obtained from these transfer functions is inevitably measured for each individual. Hereinafter, unknown (s) is referred to as individual out-of-head sound image localization information.

Further, based on the above-mentioned principle, an example in which this is realized will be described below. FIG. 4 is a block diagram showing an example of an out-of-head stereotactic headphone listening device realized by a method based on the above principle.

In FIG. 4, 1 is an input sound signal, 2 is an analog-digital (AD) converter, 3 is a convolution calculator for the right ear, 4 is a convolution calculator for the left ear, and 5 is a digital analog (DA) for the right ear. ) Converter, 6 is a digital analog (DA) converter for the left ear, and 7 is binaural headphones.

The input sound signal 1 is first converted into a digital signal by the analog-digital converter 2 in order to carry out a highly accurate operation. The digital signal of this sound is
As shown in the convolutional calculators 3 and 4 for the right and left ears of FIG. 4, the memories (M ₁ , M ₁ ) in which the result information (out-of-head sound localization information for each individual) of the equation (6) is stored in advance.
₂ , ..., M _n and M ₁ , M ₂ , ..., M _k ) The contents are subjected to convolutional integration, and the right and left ear digital-analog converters 5 and 5 for transmitting analog signals to the binaural headphones 7 and Processed via 6.

[0012]

As described above, the dedicated memories (M ₁ , M ₂ , ..., M _n and M ₁ , M ₂ , ..., M) are used.
_k ) When performing a convolution operation with the contents, an unspecified large number of out-of-head sound image localization information (head-related transfer function space) is shared.
Unless (s) and the ear canal transfer function (carnel (s)) are developed, it is technically difficult because even if an unspecified number of people listen to the sound, the same sense of localization cannot be obtained. Since there is no choice but to make a device, there is a problem in that it is considerably difficult economically.

An object of the present invention is to solve the above-mentioned problems, and to provide an economical out-of-head stereotactic headphone listening device that can be shared and used by anyone.

[0014]

SUMMARY OF THE INVENTION The present invention intends to generate a sound image for each individual in an out-of-head localization headphone listening device provided with sound image localization means for localization of a sound image outside the head using binaural headphones. The out-of-head sound image for each individual as a result of convolution of the inverse headphone impulse information and the spatial impulse information based on the spatial impulse information from the location to the specific location of the left and right ears and the headphone impulse information from the headphones to the specific location of the left and right ears. A storage card storage device having a storage card in which localization information is stored, wherein the sound image localization means includes a means for storing the storage card and outputting the stored individual out-of-head sound image localization information, and the storage card storage device. A convolution calculator for the right and left ears that performs a convolution operation between the individual out-of-head sound image localization information output from the device and the input sound signal Characterized in that it contains.

Further, according to the present invention, the storage card accommodating device reads out and outputs data from a storage card insertion detecting means for detecting that the storage card has been inserted, and a storage card inserted by designating an address. It may include read output means, reset means for resetting the device, and ideal data storage means for outputting ideal impulse information as data when the storage card is not inserted and in the reset state.

In the present invention, the storage card is an IC
It is preferably a card.

[0017]

With the use of the memory card in which the individual out-of-head sound image localization information (formula (6)) is stored, the convolution operation of the individual out-of-head sound image localization information stored in this memory card and the input sound signal is performed. ..

Therefore, by holding a dedicated memory card for each individual, it becomes possible to easily listen to the out-of-head sound image localization.

Further, as a storage card storage device, as a data when the storage card is not inserted and in a reset state,
By including the ideal data storage means for outputting the ideal impulse information (delta function) of 10000000, the input sound signal can be directly used as the output sound signal. Further, as a storage card, I including a ROM card
A C card can be used. That is, the storage card only needs to have a storage capacity of about 0.5K to 1.0K bytes, and most of the commercially available IC cards have a storage capacity of 8K.
~ 16 Kbytes is sufficient. Also, the price is 2000-3000 yen for a small number of orders, so it can be purchased at a considerably low price.

[0020]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a first embodiment of the present invention, and FIG. 2 is a block diagram showing details of a convolutional computing unit for the right ear and a storage card storage device.

In this embodiment, an analog-digital (AD) converter 2, a right-ear digital-analog (DA) converter 5, and a left ear are used as sound image localization means for localizing a sound image outside the head using the binaural headphones 7. Digital analog (D
A) In an out-of-head stereotactic headphone listening device equipped with a converter 6, spatial impulse information from a place where a sound image is to be generated to a specific place of both left and right ears, which is a feature of the present invention, and Based on the headphone impulse information from the headphones to specific locations on both the left and right ears, there is a memory card 9 in which personalized out-of-head sound localization information as a result of convolution of inverse headphone impulse information and spatial impulse information is stored. The localization means includes a storage card storage device 8 including a storage card 9 and means for outputting the stored individual out-of-head sound image localization information, and individual out-of-head sound image localization information output from the storage card storage device 8. And a convolutional calculator 3a for the right ear and a convolutional calculator 4a for the left ear, which perform a convolutional calculation with the input sound signal.

Then, the storage card storage device 8 reads out the data from the storage card 9 by specifying the address and the storage card insertion detector 14 as the storage card insertion detection means for detecting the insertion of the storage card and outputs the data. An address counter 15, a data reader 16 and an address selector 17 as read output means, a reset switch 14a as reset means for resetting the device, and ideal data as data when the storage card 9 is not inserted and in the reset state. It includes an initial storage data section 18 as an ideal data storage means for outputting impulse information.

Further, here, as the storage card 9, I
A C card is used.

The memory (temporary storage memory) in the convolutional computing unit 3a for the right ear and the convolutional computing unit 4a for the left ear
Personalized out-of-head sound image localization information output from the storage card storage device 8 is written in M _{1 to} M _n and M _{1 to} M _k .

Next, the operation of the first embodiment will be described. In FIG. 1, the same operation is performed for the right ear and the left ear, and therefore the right ear will be described with reference to FIG.

First, when the storage card 9 is inserted into the storage card storage device 8, the storage card insertion detector 14 operates and the designated address is input from the address counter 15 to the address information of the storage card 9, and the address is stored. The data content stored in the number (out-of-head sound localization information for each individual) is read from the storage card 9 by the data reader 16. The address information is output to the address selector 17 together with the read data content, and the address selector 17 sends the data content to the right ear convolution operation unit 3a according to each designated address.

Then, the output data contents are respectively written in the memories M _{1 to} M _n of the right ear convolution calculator 3a, and the convolution operation with the digital input sound signal is performed, and the result is the right ear digital signal. It is output to the right earphone of the binaural headphones 7 via the analog converter 5.

Normally, when the storage card 9 is not inserted in the storage card storage device 8, the data reader 16 does not operate and the initial storage data section 18 operates. That is, the address counter 15 and the initial storage data unit 18 operate. Further, when the reset switch 14a operates and enters the reset state regardless of whether the storage card 9 is inserted or not, the address counter 15 and the initial storage data unit 18 also operate.

The initial storage data section 18 is a fixed storage and has impulse information, that is, 1000000000.
The ideal impulse information (delta function) of 0 is inserted, and the ideal impulse information is output to the right ear convolution calculator 3a instead of the individual out-of-head sound image localization information. As a result, the input sound signal 1 is sent as it is to the output sound signal and the binaural headphones 7.

FIG. 3 is a block diagram showing a second embodiment of the present invention, which is an example in which the present invention is applied to a two-channel stereo system having both left and right channels.

In the second embodiment, instead of the analog-digital converter 2 in the first embodiment of FIG. 1, a right channel analog-digital (AD) converter 12 for converting the right analog input signal 10 into a digital signal, An analog-to-digital (AD) converter 13 for the left channel for digitally converting the left analog input signal 11 is provided.

Therefore, the operation is similar to that of the first embodiment shown in FIG.

In the first and second embodiments, the convolution calculators 3a and 4a for the right and left ears are used.
Is a DSP (Digital Signal Processor)-
An IC can be used. That is, the recent DSP processor-IC has a processing time of 1 n product sum calculation of 60 nsec.
Since the impulse response length of the out-of-head sound image localization information for each individual is about 32 msec, a 512 tap FIR digital filter is required for 16 kHz sampling, and 512 × 60≈31 μsec, that is, 16 k
It has reached a technical level capable of sufficiently processing in Hz sampling time (62.5 μsec).

If the input sound signal 1, the right analog input signal 10 and the left analog input signal 11 are digital signals, the analog-digital converters 2, 12 and 13 are unnecessary.

Further, since the input sound signal becomes the output sound signal in the reset state, it is possible to use a normal equalizer amplifier.

[0037]

As described above, according to the present invention, the memory card stores individual out-of-head sound localization information unique to the listener,
By transferring this information from the memory card to the convolutional arithmetic unit when necessary, even if an unspecified number of people listen to it, if the memory card is possessed, it is possible to perceive the sound image localization feeling easily and accurately. In addition to being able to do so, it is possible to share the out-of-head sound image localization device, and there is an effect that the cost can be reduced.

Further, when the storage card is not inserted or when there is some kind of trouble, the reset switch is provided so that the input sound signal becomes the output sound signal as it is, so that the input sound signal is cut off. There is also an effect that the listener does not feel uncomfortable.

[Brief description of drawings]

FIG. 1 is a block diagram showing the first embodiment of the present invention.

FIG. 2 is a block configuration diagram showing details of a convolutional computing unit for the right ear and a storage card storage device of FIG.

FIG. 3 is a block diagram showing a second embodiment of the present invention.

FIG. 4 is a block diagram showing a conventional example.

FIG. 5 is an explanatory diagram showing the principle of out-of-head sound image localization.

[Explanation of symbols]

 1 Input sound signal 2 Analog-to-digital (AD) converter 3, 3a Right-ear convolutional calculator 4, 4a Left-ear convolutional calculator 5 Right-ear digital-analog (DA) converter 6 Left-ear digital analog (DA) Converter 7 Binaural headphones 8 Storage card storage device 9 Storage card 10 Right analog input signal 11 Left analog input signal 12 Right channel analog digital (AD) converter 13 Left channel analog digital (AD) converter 14 Storage card insertion Detector 14a Reset switch 15 Address counter 16 Data reader 17 Address selector 18 Initial storage data section

Claims (3)

[Claims] 1. In an out-of-head localization headphone listening device equipped with sound image localization means for localization of a sound image outside the head using binaural headphones, identification of the left and right ears from the place where a sound image is to be generated for each individual. A memory card that stores individual out-of-head sound localization information as a result of convolution of inverse headphone impulse information and spatial impulse information based on the spatial impulse information up to the location and the headphone impulse information from the headphones to specific locations on the left and right ears. The sound image localization means includes a memory card storage device including a means for accommodating the storage card and outputting the stored personalized out-of-person sound image localization information, and a personalized head output from the storage card storage device. A head including convolutional calculators for the right and left ears, which perform a convolutional calculation of external sound image localization information and an input sound signal Localization headphone listening devices. 2. The storage card accommodation device includes storage card insertion detection means for detecting that the storage card has been inserted, and read output means for reading and outputting data from the storage card inserted by designating an address. 2. The out-of-head stereophonic headphone listening apparatus according to claim 1, further comprising reset means for resetting the device, and ideal data storage means for outputting ideal impulse information as data when the storage card is not inserted and in the reset state. 3. The out-of-head stereotactic headphone listening device according to claim 1, wherein the storage card is an IC card.