Earphone control method and earphone

Abstract

This application relates to a headphone control method and a headphone. The method is applied to a headphone, which includes a feedforward microphone and a feedback microphone. The method includes: acquiring a first audio signal through the feedforward microphone and a second audio signal through the feedback microphone; determining the current scene type of the external environment in which the headphone is located based on the first audio signal, and acquiring a target effect audio signal corresponding to the current scene type; determining the current spectral relationship information between the first and second audio signals, and the target spectral relationship information between the first audio signal and the target effect audio signal; iteratively adjusting the headphone's filter parameters according to the current spectral relationship information and the target spectral relationship information; and ensuring that the error between the second audio signal acquired again and the target effect audio signal is less than a preset error. This method can improve the listening experience of the headphone when worn.

Description

Technical Field

[0001] This application relates to the field of sound processing technology, and in particular to a headphone control method and headphones. Background Technology

[0002] With the development of audio processing technology, headphones have introduced pass-through and active noise cancellation modes. In pass-through mode, headphones transmit ambient sounds to the user's ears, while in active noise cancellation mode, they filter out ambient noise. Traditionally, regardless of whether it's pass-through or active noise cancellation, headphones typically use fixed filter parameters to process external sound signals. However, users often have different audio listening experience requirements for different environments. Therefore, once the filter parameters are fixed, the actual audio experience may not match the user's desired audio quality, resulting in a poor listening experience. Summary of the Invention

[0003] Therefore, it is necessary to provide a headphone control method and headphones that can improve the listening experience after wearing headphones, in order to address the above-mentioned technical problems.

[0004] In a first aspect, this application provides a headphone control method applied to headphones, the headphones including a feedforward microphone and a feedback microphone; the method includes:

[0005] A first audio signal is acquired through the feedforward microphone and a second audio signal is acquired through the feedback microphone;

[0006] Based on the first audio signal, determine the current scene type of the external scene where the headphones are located, and obtain the target effect audio signal corresponding to the current scene type;

[0007] Determine the current spectral relationship information between the first audio signal and the second audio signal, and the target spectral relationship information between the first audio signal and the target effect audio signal;

[0008] The filter parameters of the headphones are adjusted based on the current spectrum relationship information and the target spectrum relationship information.

[0009] The second audio signal is acquired again based on the adjusted filter parameters;

[0010] If it is determined that the error between the second audio signal acquired again and the target effect audio signal is greater than or equal to a preset error, then the process returns to the steps of acquiring the first audio signal through the feedforward microphone and acquiring the second audio signal through the feedback microphone, until the error between the second audio signal acquired again and the target effect audio signal is less than the preset error.

[0011] Secondly, this application also provides an earphone control device for use with earphones, the earphones including a feedforward microphone and a feedback microphone; the device includes:

[0012] A signal acquisition module is used to acquire a first audio signal through the feedforward microphone and a second audio signal through the feedback microphone;

[0013] The signal acquisition module is used to determine the current scene type of the external scene where the headphones are located based on the first audio signal, and to acquire the target effect audio signal corresponding to the current scene type;

[0014] The spectrum relationship information determination module is used to determine the current spectrum relationship information between the first audio signal and the second audio signal, and the target spectrum relationship information between the first audio signal and the target effect audio signal;

[0015] The parameter adjustment module is used to adjust the filter parameters of the headphones according to the current spectrum relationship information and the target spectrum relationship information;

[0016] The signal acquisition module is also used to acquire the second audio signal again according to the adjusted filter parameters;

[0017] An iterative loop module is used to determine if the error between the second audio signal acquired again and the target effect audio signal is greater than or equal to a preset error. If so, it returns to the steps of acquiring the first audio signal through the feedforward microphone and acquiring the second audio signal through the feedback microphone, until the error between the second audio signal acquired again and the target effect audio signal is less than the preset error.

[0018] Thirdly, this application also provides an earphone, including a feedforward microphone, a feedback microphone, a memory, and a processor, wherein the memory stores a computer program, and the processor executes the computer program to perform the following steps:

[0019] The system acquires a first audio signal via a feedforward microphone and a second audio signal via a feedback microphone; based on the first audio signal, it determines the current scene type of the external environment in which the headphones are located, and obtains the target effect audio signal corresponding to the current scene type; it determines the current spectral relationship information between the first audio signal and the second audio signal, and the target spectral relationship information between the first audio signal and the target effect audio signal; it adjusts the filter parameters of the headphones according to the current spectral relationship information and the target spectral relationship information; it acquires the second audio signal again according to the adjusted filter parameters; if it is determined that the error between the re-acquired second audio signal and the target effect audio signal is greater than or equal to a preset error, it returns to the steps of acquiring the first audio signal via the feedforward microphone and acquiring the second audio signal via the feedback microphone, until the error between the re-acquired second audio signal and the target effect audio signal is less than the preset error.

[0020] Fourthly, this application also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, performs the following steps:

[0021] The system acquires a first audio signal via a feedforward microphone and a second audio signal via a feedback microphone; based on the first audio signal, it determines the current scene type of the external environment in which the headphones are located, and obtains the target effect audio signal corresponding to the current scene type; it determines the current spectral relationship information between the first audio signal and the second audio signal, and the target spectral relationship information between the first audio signal and the target effect audio signal; it adjusts the filter parameters of the headphones according to the current spectral relationship information and the target spectral relationship information; it acquires the second audio signal again according to the adjusted filter parameters; if it is determined that the error between the re-acquired second audio signal and the target effect audio signal is greater than or equal to a preset error, it returns to the steps of acquiring the first audio signal via the feedforward microphone and acquiring the second audio signal via the feedback microphone, until the error between the re-acquired second audio signal and the target effect audio signal is less than the preset error.

[0022] Fifthly, this application also provides a computer program product, including a computer program that, when executed by a processor, performs the following steps:

[0023] The system acquires a first audio signal via a feedforward microphone and a second audio signal via a feedback microphone; based on the first audio signal, it determines the current scene type of the external environment in which the headphones are located, and obtains the target effect audio signal corresponding to the current scene type; it determines the current spectral relationship information between the first audio signal and the second audio signal, and the target spectral relationship information between the first audio signal and the target effect audio signal; it adjusts the filter parameters of the headphones according to the current spectral relationship information and the target spectral relationship information; it acquires the second audio signal again according to the adjusted filter parameters; if it is determined that the error between the re-acquired second audio signal and the target effect audio signal is greater than or equal to a preset error, it returns to the steps of acquiring the first audio signal via the feedforward microphone and acquiring the second audio signal via the feedback microphone, until the error between the re-acquired second audio signal and the target effect audio signal is less than the preset error.

[0024] The aforementioned headphone control method and headphones, after acquiring a first audio signal through the feedforward microphone and a second audio signal through the feedback microphone, first determine the current scene type of the external scene in which the headphones are located based on the first audio signal, and acquire the target effect audio signal corresponding to the current scene type. Then, they determine the current spectral relationship information representing the spectral relationship between the first and second audio signals, and the target spectral relationship information representing the spectral relationship between the first and target effect audio signals. Thus, based on the current spectral relationship information and the target spectral relationship information, the headphone's filter parameters are iteratively adjusted, enabling the second audio signal acquired by the feedback microphone to be more effective. The audio signal gradually approaches the target effect audio signal until the signal error between the second audio signal collected by the feedback microphone and the target effect audio signal is less than the preset error. At this point, the sound signal heard by the user is basically consistent with the target effect audio signal. Since the target effect audio signal corresponds to the current scene type of the external scene in which the headphones are located, the listening effect of the target effect audio signal is matched with the external environment in which the headphones are located. At this point, the listening effect after the user puts on the headphones can always be close to the sound effect of the target effect audio signal and match the external environment in which the headphones are located. In this way, the listening effect of the headphones can be stabilized at a good level, thus improving the listening effect after wearing the headphones. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the drawings used in the description of the embodiments of this application or related technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a flowchart illustrating a headphone control method in one embodiment of this application;

[0027] Figure 2 This is a flowchart illustrating the process of adjusting the filter parameters of headphones in one embodiment of this application;

[0028] Figure 3 This is a structural block diagram of the headphone control device in one embodiment of this application;

[0029] Figure 4 This is a diagram of the internal structure of the headphones in one embodiment of this application. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0031] In one embodiment, such as Figure 1 As shown, a headphone control method is provided. This embodiment illustrates the application of this method to headphones, which include a feedforward microphone and a feedback microphone. It is understood that this embodiment does not limit the form of the headphones; the headphones can be wireless Bluetooth headphones, over-ear headphones, etc. In this embodiment, the method includes the following steps:

[0032] Step 202: Acquire the first audio signal through the feedforward microphone and the second audio signal through the feedback microphone.

[0033] Headphones typically have pass-through and noise-canceling modes. In pass-through mode, the headphones can transmit external sound signals to the user, while in noise-canceling mode, the headphones will block external sound signals as noise. Headphones are equipped with a feedforward microphone (reference microphone) and a feedback microphone (error microphone). The feedforward microphone is usually located on the area of ​​the headphones that is in contact with the outside space to collect external sound signals. The feedback microphone is usually located on the side of the headphones facing the user's ear canal to collect the audio signals transmitted into the user's ear canal. The audio signals collected by the feedback microphone can be used as the real audio signals that the user actually hears.

[0034] It should be noted that the first audio signal is the external sound signal collected by the feedforward microphone, and the second audio signal is the sound signal that the external sound signal is transmitted to the feedback microphone and collected by the feedback microphone.

[0035] Step 204: Determine the current scene type of the external scene where the headphones are located based on the first audio signal, and obtain the target effect audio signal corresponding to the current scene type.

[0036] In different external scenarios, users usually have different requirements for the sound effect. For example, in an airport scenario, users usually want to filter out the noise of airplanes taking off and landing, but retain the voices of other people. In a sleep scenario, users usually want to block out the snoring of other people, but retain the sound of the alarm clock and other voices.

[0037] It should be noted that this embodiment sets up effect audio signals for various types of external scenes. Each effect audio signal is evenly matched with the type of external scene, which can bring users a better listening experience in the corresponding type of external scene.

[0038] As an example, step 204 includes: extracting audio signal features from the first audio signal, classifying the audio signal features to obtain feature classification results, and determining the current scene type of the external scene where the headphones are located based on the feature classification results. The audio signal features represent at least one of the amplitude and frequency features of the first audio signal.

[0039] In one embodiment, determining the current scene type of the external environment in which the headphones are located based on the first audio signal includes:

[0040] Extract audio signal features from the first audio signal; determine the current scene type of the external scene where the headphones are located based on the audio signal features.

[0041] Specifically, the first audio signal is converted from the time domain to the frequency domain to obtain the first spectrum signal corresponding to the first audio signal; based on the spectrum signal characteristics of the first spectrum signal in each preset frequency band, the current scene type of the external scene where the headphones are located is detected.

[0042] In addition, in this embodiment, when a change in the external scene where the headphones are located is detected, the following steps can be triggered: detect the current scene type of the external scene where the headphones are located based on the first audio signal, and obtain the scene type identifier; use the scene type identifier as an index to find the target effect audio signal corresponding to the scene type identifier.

[0043] In some embodiments, when a change in the external scene surrounding the headphones is detected, the current scene type of the external scene surrounding the headphones can be detected based on the first audio signal to obtain a scene type identifier. This scene type identifier is then pushed to the terminal device corresponding to the headphones. The terminal device displays multiple corresponding effect audio signals based on the scene type identifier. These corresponding effect audio signals are all audio signals with good listening effects in the scene corresponding to the scene type identifier. In response to the user's selection operation, the terminal device selects a target effect audio signal from the multiple corresponding effect audio signals and pushes the target effect audio signal to the headphones. The headphones receive the target effect audio signal fed back by the terminal device. The selection operation can be a click operation, a text input operation, or a selection box operation, etc.

[0044] As an example, the headphones include a motion detection module; detecting whether the external environment in which the headphones are located has changed, including:

[0045] The movement detection module on the earphone detects the displacement distance of the earphone in the external environment. If the displacement distance is greater than a preset distance threshold, it is considered that the external scene of the earphone has changed; if the displacement distance is less than or equal to the preset distance threshold, it is considered that the external scene of the earphone has not changed.

[0046] It should be noted that the target effect audio signal can be an audio signal characterizing the headphone's pass-through effect, an audio signal characterizing the headphone's active noise cancellation effect, or an audio signal characterizing both the headphone's pass-through effect and active noise cancellation effect. Therefore, the target effect audio signal must include at least one of the following:

[0047] Full-band active noise cancellation for audio signals;

[0048] Full-band pass-through effect for audio signals;

[0049] The audio signals with active noise reduction effect in multiple first frequency bands and the audio signals with pass-through effect in multiple second frequency bands, wherein the multiple first frequency bands and the multiple second frequency bands constitute the above-mentioned full frequency band.

[0050] Step 206: Determine the current spectral relationship information between the first audio signal and the second audio signal, and the target spectral relationship information between the first audio signal and the target effect audio signal.

[0051] The target effect audio signal is an audio signal with the expected listening effect, which matches the external environment. If the spectrum of the second audio signal transmitted from the external sound signal to the feedback microphone is close to the spectrum of the target effect audio signal, it is considered that the headphones currently have the expected listening effect, and the user's listening experience when wearing the headphones in the current external scenario is good.

[0052] As an example, step 206 includes: converting the first audio signal from the time domain to the frequency domain to obtain a first spectrum signal corresponding to the first audio signal, and converting the second audio signal from the time domain to the frequency domain to obtain a second spectrum signal corresponding to the second audio signal; determining current spectrum relationship information between the first spectrum signal and the second spectrum signal, wherein the current spectrum relationship information is used to characterize the spectrum relationship between the first audio signal and the second audio signal; and determining target spectrum relationship information between the first spectrum signal corresponding to the first audio signal and the third spectrum signal corresponding to the target effect audio signal, wherein the target spectrum relationship information is used to characterize the spectrum relationship between the first audio signal and the target effect audio signal.

[0053] As an example, determining the current spectral relationship information between the first spectral signal and the second spectral signal includes:

[0054] The signal ratio between the second spectral signal and the first spectral signal is calculated to obtain the current spectral relationship information.

[0055] Specifically, the first sample value of the first spectrum signal at each preset frequency and the second sample value of the second spectrum signal at each preset frequency can be obtained; the ratio between the second sample value and the first sample value at each preset frequency can be calculated to obtain the ratio of the first sample value at each preset frequency; and the ratio of the first sample value at each preset frequency can be used as the current spectrum relationship information.

[0056] As an example, determining the target spectral relationship information between the first spectral signal corresponding to the first audio signal and the third spectral signal corresponding to the target effect audio signal includes:

[0057] The signal ratio between the third spectrum signal and the first spectrum signal is calculated to obtain the target spectrum relationship information.

[0058] Specifically, the first sample value of the first spectrum signal at each preset frequency and the third sample value of the third spectrum signal at each preset frequency are obtained; the ratio between the third sample value and the first sample value at each preset frequency is calculated to obtain the ratio of the second sample value at each preset frequency; and the ratio of the second sample value at each preset frequency is used as the target spectrum relationship information.

[0059] Step 208: Adjust the headphone filter parameters according to the current spectrum relationship information and the target spectrum relationship information; and collect the second audio signal again according to the adjusted filter parameters.

[0060] The filter parameters can be the gain at each preset frequency. Based on the gain at the preset frequency, the amplitude of the sound signal at the preset frequency can be adjusted.

[0061] It should be noted that if the filter parameters of the headphones change, the sound signal transmitted from the outside sound signal to the ear canal will also change, and therefore the second audio signal collected by the feedback microphone will also change.

[0062] As an example, step 208 includes: calculating the difference between the current spectrum relationship information and the target spectrum relationship information to obtain spectrum deviation information; and adjusting the filter parameters of the headphones based on the spectrum deviation information.

[0063] Step 210: If the error between the second audio signal acquired again and the target effect audio signal is greater than or equal to the preset error, then return to the steps of acquiring the first audio signal through the feedforward microphone and acquiring the second audio signal through the feedback microphone, until the error between the second audio signal acquired again and the target effect audio signal is less than the preset error.

[0064] The signal error between the second audio signal and the target effect audio signal can be the spectral signal error between the second spectrum signal corresponding to the second audio signal and the third spectrum signal corresponding to the target effect audio signal.

[0065] As an example, step 210 includes: if the signal error between the second audio signal re-acquired by the feedback microphone and the target effect audio signal is greater than or equal to a preset error, then the steps of acquiring the first audio signal through the feedforward microphone and acquiring the second audio signal through the feedback microphone are re-executed to redetermine the current spectrum relationship information and the target spectrum relationship signal, until the error between the second audio signal re-acquired by the feedback microphone and the target effect audio signal is less than the preset error.

[0066] It should be noted that if the signal error between the second audio signal collected again by the feedback microphone and the target effect audio signal is less than the preset error, it means that the headphone filter parameter adjustment is complete and the adjusted filter parameters meet the requirements.

[0067] As an example, the current spectrum relationship information includes the ratio of the first sampled values ​​at each preset frequency, and the target spectrum relationship information includes the ratio of the second sampled values ​​at each preset frequency; the difference between the current spectrum relationship information and the target spectrum relationship information is calculated to obtain spectrum deviation information; based on this spectrum deviation information, the filter parameters of the headphones are adjusted, including:

[0068] Calculate the difference between the ratio of the first sampled value and the ratio of the second sampled value at each preset frequency to obtain the ratio difference at each preset frequency. Use the ratio differences at each preset frequency as the spectrum deviation information. Based on the mapping relationship between the ratio difference and the parameter adjustment information, find the parameter adjustment information corresponding to the ratio difference at each preset frequency. Based on the parameter adjustment information at each preset frequency, adjust the filter parameters of the headphones at each preset frequency.

[0069] It should be noted that the mapping relationship between the ratio difference and parameter adjustment information in this embodiment can be a fixed mapping relationship. However, due to differences in ear canal structure and headphone wearing status among different users, the headphone's listening effect cannot usually be directly adjusted to match the listening effect of the target audio signal after the first adjustment of the headphone's filter parameters. However, in this embodiment, the spectral deviation information is continuously determined based on the first audio signal collected by the feedforward microphone and the second audio signal collected by the feedback microphone. The headphone's filter parameters are then iteratively adjusted using this spectral deviation information. During the continuous adjustment of the headphone's filter parameters, the second audio signal collected by the feedback microphone gradually approaches the target audio signal, eventually achieving the desired headphone listening effect, that is, the headphone's listening effect is close to the sound effect of the target audio signal. Therefore, even if there are differences in ear canal structure and headphone wearing status among different users, this embodiment can always adjust the second audio signal collected by the feedback microphone to be close to the target audio signal, that is, adjust the headphone's listening effect to match the external environment in which the headphone is located, thus improving the listening effect after wearing the headphone.

[0070] In the aforementioned headphone control method, after acquiring a first audio signal via a feedforward microphone and a second audio signal via a feedback microphone, the current scene type of the external environment in which the headphones are located is first determined based on the first audio signal, and the target effect audio signal corresponding to the current scene type is obtained. Then, the current spectral relationship information representing the spectral relationship between the first and second audio signals, and the target spectral relationship information representing the spectral relationship between the first audio signal and the target effect audio signal are determined. Thus, based on the current spectral relationship information and the target spectral relationship information, the headphone's filter parameters are iteratively adjusted, enabling the second audio signal acquired by the feedback microphone to... The signal gradually approaches the target effect audio signal until the signal error between the second audio signal collected by the feedback microphone and the target effect audio signal is less than the preset error. At this point, the sound signal heard by the user is basically consistent with the target effect audio signal. Since the target effect audio signal corresponds to the current scene type of the external scene in which the headphones are located, the listening effect of the target effect audio signal is matched with the external environment in which the headphones are located. At this point, the listening effect after the user puts on the headphones can always be close to the sound effect of the target effect audio signal and match the external environment in which the headphones are located. In this way, the listening effect of the headphones can be stabilized at a good level, thus improving the listening effect after wearing the headphones.

[0071] In one exemplary embodiment, such as Figure 2 As shown, based on the current spectrum relationship information and the target spectrum relationship information, the headphone filter parameters are adjusted, including:

[0072] Step 302: Calculate the deviation between the current spectrum relationship information and the target spectrum relationship information to obtain the first spectrum deviation information.

[0073] The current spectrum relationship information can be the ratio of the first sample value to the second sample value and the first sample value at each preset frequency. The target spectrum relationship information can be the ratio of the second sample value to the third sample value and the first sample value at each preset frequency. The first sample value is the sample value at the preset frequency in the first spectrum signal corresponding to the first audio signal. The second sample value is the sample value at the preset frequency in the second spectrum signal corresponding to the second audio signal. The third sample value is the sample value at the preset frequency in the third spectrum signal corresponding to the target effect audio signal.

[0074] As an example, step 302 includes: calculating the difference between the ratio of the first sampled value and the ratio of the second sampled value at each preset frequency to obtain the ratio difference at each preset frequency; and using the ratio difference at each preset frequency as the first spectral deviation information.

[0075] Step 304: Determine the first parameter adjustment information corresponding to the filter parameters of the headphones based on the preset transfer function and the first spectral deviation information.

[0076] The preset transfer function can be a pre-set transfer function from the sound played by the headphone speaker to the feedback microphone. This preset transfer function is affected by the user's ear canal structure and the headphone wearing status, which can be the tightness of the headphone.

[0077] As an example, step 304 includes: calculating the first parameter adjustment information corresponding to the filter parameters of the headphones based on the preset transfer function and the first spectral deviation information.

[0078] In one embodiment, the first parameter adjustment information includes the parameter adjustment magnitude and parameter adjustment direction; determining the first parameter adjustment information corresponding to the headphone filter parameters based on the preset transfer function and the first spectral deviation information includes:

[0079] Based on the first spectral deviation information, the signal amplitude deviation between the first audio signal and the second audio signal in each preset frequency band is determined; based on the signal amplitude deviation in each preset frequency band and the preset transfer function, the parameter adjustment magnitude and parameter adjustment direction of the headphone filter parameters in each preset frequency band are determined.

[0080] Specifically, the deviation values ​​at each preset frequency in the first spectral deviation information are obtained, where the deviation value is the difference between the ratio of the first sample value and the ratio of the second sample value at the preset frequency; the deviation values ​​corresponding to the preset frequency in each preset frequency band are averaged to obtain the signal amplitude deviation between the first spectral signal corresponding to the first audio signal and the second spectral signal corresponding to the second audio signal in each preset frequency band; based on the signal amplitude deviation in each preset frequency band and the preset transfer function, the parameter adjustment amplitude and parameter adjustment direction of the headphone filter parameters in each preset frequency band are calculated, where the parameter adjustment amplitude can be the absolute value of the first parameter adjustment information, and the parameter adjustment direction is positively or negatively related to the first parameter adjustment information. For example, if the value of the first parameter adjustment information is positive, the parameter adjustment direction is decreasing; if the value of the first parameter adjustment information is negative, the parameter adjustment direction is increasing.

[0081] As an example, the specific formula for calculating the adjustment information of the first parameter corresponding to the filter parameters of the headphones is as follows:

[0082] (1)

[0083] in, Adjustment information for the first parameter. To adjust the previous filter parameters, To adjust the filter parameters, For the preset transfer function, The second audio signal is the sound signal collected by the feedback microphone after the external sound signal is transmitted to it. For the target effect audio signal, The external sound signal, i.e., the first audio signal, is collected by the feedforward microphone. This is the current spectrum relationship information. For target spectrum relationship information, This represents the deviation between the current spectrum relationship information and the target spectrum relationship information.

[0084] It is easy to see from equation (1) that the preset transfer function is set to a fixed value in this embodiment. However, since each user's ear canal structure and headphone wearing state are different, the preset transfer function is still different from the actual transfer function from the sound played by the headphone speaker to the feedback microphone. However, the above equation (1) is based on The difference is used to iteratively adjust the filter parameters, therefore, during the iterative adjustment process, It will keep getting closer ,final will with When the sound quality approaches consistency, the perceived sound effect of the user is always close to that of the target sound signal. Therefore, in this embodiment, the adjustment process of the headphone sound quality is not affected by the user's ear canal structure or the headphone wearing status. The sound quality of the headphone can always be stabilized at a good level, thus always matching the external environment in which the headphone is located.

[0085] As an example, the derivation of equation (1) above is as follows:

[0086]

[0087]

[0088] Subtracting equation (2) from equation (3) yields equation (1), where, To adjust the previous filter parameters, To adjust the filter parameters, For the preset transfer function, The second audio signal is the sound signal collected by the feedback microphone after the external sound signal is transmitted to it. For the target effect audio signal, The external sound signal, i.e., the first audio signal, is collected by the feedforward microphone. The audio signal played by the headphones through the speaker, such as music or call audio signals. External sound signals are transmitted directly to the feedforward microphone without passing through a speaker. The feedforward microphone picks up the sound signal. Under normal circumstances, external sound signals are collected by the feedforward microphone to obtain the first audio signal. The first audio signal, after being filtered, is played by the speaker and then transmitted to the feedback microphone. However, due to material limitations, headphones cannot completely isolate sound, so some external sound signals will pass directly through the headphones to the feedback microphone, where they will be picked up and formed. .

[0089] Step 306: Adjust the filter parameters of the headphones according to the first parameter adjustment information.

[0090] The headphone's filter parameters may include filter parameters for each preset frequency band, which are used to filter external sound signals for each preset frequency band respectively; the first parameter adjustment information may include the parameter adjustment direction and parameter adjustment range corresponding to each preset frequency band.

[0091] As an example, step 306 includes: adjusting the filter parameters under each preset frequency band according to the parameter adjustment direction and parameter adjustment magnitude corresponding to each preset frequency band.

[0092] In this embodiment, each user's ear canal structure and headphone wearing status are different. Therefore, the preset transfer function and the actual transfer function from the headphone speaker to the feedback microphone are still different. Therefore, the preset transfer function is set to a fixed value. Although it is not possible to adjust the headphone's listening effect to be close to the listening effect of the target audio signal in one go, the headphone's filter parameters are continuously adjusted iteratively based on the deviation between the current spectrum relationship information and the target spectrum relationship information. During the iteration process, the current spectrum relationship information will continuously approach the target spectrum relationship information and eventually become consistent. At this time, the listening effect perceived by the user can always be close to the listening effect of the target audio signal. Therefore, the adjustment process of the headphone's listening effect in this embodiment is not affected by the user's ear canal structure and headphone wearing status. The headphone's listening effect can always be stabilized at a good level and can always match the external environment in which the headphone is located, thus improving the listening effect after wearing the headphone.

[0093] In one embodiment, the headphones are equipped with multiple feedforward microphones corresponding to multiple sound transmission directions. The first audio signal includes external sound signals from multiple sound transmission directions. The current spectrum relationship information includes first spectrum relationship information corresponding to the external sound signals from multiple sound transmission directions. The target spectrum relationship information includes second spectrum relationship information corresponding to the external sound signals from multiple sound transmission directions. Based on the current spectrum relationship information and the target spectrum relationship information, the headphone's filter parameters are adjusted, including:

[0094] The deviation between the first spectral relationship information and the second spectral relationship information in each sound transmission direction is calculated to obtain the second spectral deviation information in each sound transmission direction; based on the second spectral deviation information in each sound transmission direction, the second parameter adjustment information corresponding to the headphone filter parameters in each sound transmission direction is determined; based on the second parameter adjustment information, the headphone filter parameters in each sound transmission direction are adjusted respectively.

[0095] The headphones can be equipped with multiple feedforward microphones, which can be used to collect external sound signals from different sound transmission directions, such as left and right or front and back. The first spectral relationship information can be the ratio of the first sample value to the second sample value at each preset frequency in a sound transmission direction, and the second spectral relationship information can be the ratio of the second sample value to the first sample value at each preset frequency in a sound transmission direction.

[0096] Specifically, for the first spectral relationship information and the second spectral relationship information in each sound transmission direction, the difference between the ratio of the first sampled value and the ratio of the second sampled value at each preset frequency is calculated to obtain the ratio difference at each preset frequency; the ratio difference at each preset frequency in each sound transmission direction is used as the second spectral deviation information; based on the preset transfer function and the second spectral deviation information in each sound transmission direction, the second parameter adjustment information corresponding to the headphone filter parameters in each sound transmission direction is calculated; for each sound transmission direction, the headphone filter parameters in the sound transmission direction are adjusted according to the second parameter adjustment information.

[0097] As an example, the specific calculation process for the second parameter adjustment information can be referred to the specific calculation process for the first parameter adjustment information described above, and will not be repeated here.

[0098] As an example, the filter parameters of the headphones are adjusted according to the parameter adjustment direction and parameter adjustment magnitude in the second parameter adjustment information.

[0099] In one embodiment, the headphone control method further includes:

[0100] In response to the first adjustment command, adjust the signal amplitude of the target effect audio signal.

[0101] The first adjustment command can be determined by the user touching or clicking on the headphone itself, or by the user operating on a terminal device connected to the headphone. The first adjustment command is used to adjust the overall signal amplitude of the target effect audio signal, that is, to lower or raise the overall signal amplitude of the target effect audio signal in each preset frequency band.

[0102] In one embodiment, the headphone control method further includes:

[0103] In response to the second adjustment command, the signal amplitude distribution of the target effect audio signal in each preset frequency band is adjusted.

[0104] The second adjustment command can be determined by the user by touching or clicking on the earphone itself, or by the user operating on a terminal device connected to the earphone. The second adjustment command is used to adjust the frequency response characteristics of the target effect audio signal in each preset frequency band, so that the target effect audio signal is more in line with the user's expectations. For example, the frequency response characteristics of the preset frequency band corresponding to the human voice can be adjusted separately to enhance the human voice. The frequency response characteristics can characterize the relationship between the amplitude and phase of the sound signal and the frequency.

[0105] In one embodiment, the headphone control method further includes:

[0106] In response to the third adjustment command, the signal amplitude of the target effect audio signal in the target transmission direction is adjusted.

[0107] The third adjustment command can be determined by the user touching or clicking on the headphone itself, or by the user operating on a terminal device connected to the headphone. This third adjustment command is used to adjust the signal strength of the target effect audio signal in the target transmission direction, thereby achieving individual adjustment of the target effect audio signal in the target transmission direction. This allows for individual adjustment of the headphone's listening effect in a single sound transmission direction.

[0108] In one embodiment, the headphone control method further includes:

[0109] In response to the fourth adjustment command, the signal amplitude distribution of the target effect audio signal in each preset frequency band is adjusted in the target transmission direction.

[0110] The fourth adjustment command can be determined by the user by touching or clicking on the earphone itself, or by the user operating on a terminal device connected to the earphone. This fourth adjustment command is used to adjust the frequency response characteristics of the target effect audio signal in each preset frequency band in the target transmission direction, so that the target effect audio signal in the target transmission direction is more in line with the user's expectations. For example, the frequency response characteristics of the preset frequency band corresponding to the human voice can be adjusted separately in the target transmission direction, thereby achieving human voice enhancement in a single sound transmission direction. The frequency response characteristics can characterize the relationship between the amplitude and phase of the sound signal and its frequency.

[0111] In one embodiment, the headphone control method further includes:

[0112] The wearing status of the headphones is detected in real time; if the wearing status of the headphones changes, the steps of determining the current spectral relationship information between the first audio signal and the second audio signal, as well as the target spectral relationship information between the first audio signal and the target effect audio signal are triggered.

[0113] The wearing status can be the wearing position or the tightness of the headphones. In this embodiment, the wearing status of the headphones can be detected in real time. If the wearing status changes, it means that the sound effect of the headphones will be affected, thus triggering the real-time detection of the wearing status of the headphones.

[0114] If the wearing status of the headphones changes, the system triggers the steps of determining the current spectral relationship between the first and second audio signals, as well as the target spectral relationship between the first audio signal and the target effect audio signal, to adjust the headphone's listening experience and stabilize it at a good level. In this way, even if the headphone's listening experience is affected by changes in wearing status, the headphones can automatically adjust and trigger the spectral information determination, thereby automatically adjusting the headphone's listening experience to its optimal level.

[0115] It should be noted that in this embodiment, the headphones can be configured to detect the current scene type of the external scene in real time. For example, the scene type of the external scene in which the headphones are located can be detected based on at least one of the time-domain signal characteristics and frequency-domain signal characteristics of the first audio signal. However, the process of detecting the scene type of the external scene in which the headphones are located based on at least one of the time-domain signal characteristics and frequency-domain signal characteristics of the first audio signal usually requires the use of an AI model. This AI model requires high computing power, which will lead to excessive power consumption of the headphones. Therefore, it is possible to first detect whether the scene type of the external scene in which the headphones are located has changed. Only when the scene type of the external scene in which the headphones are located changes will the process of detecting the scene type of the external scene in which the headphones are located based on at least one of the time-domain signal characteristics and frequency-domain signal characteristics of the first audio signal be triggered.

[0116] In one embodiment, the above-described headphone control method further includes:

[0117] The system obtains the scene type previously detected by the headphones and determines the target detection frequency band based on the previously detected scene type. If the change in the signal amplitude of the first audio signal in the target detection frequency band is greater than a preset change threshold, it is determined that the scene type of the external scene where the headphones are located has changed, and the step of determining the current scene type of the external scene where the headphones are located based on the first audio signal is executed. If the change in the signal amplitude of the first audio signal in the target detection frequency band is not greater than the preset change threshold, it is determined that the scene type of the external scene where the headphones are located has not changed, and the previously detected scene type is determined as the current scene type of the external scene where the headphones are located.

[0118] Among them, the target effect audio features of different scene types usually have specific sound signal distribution features in certain frequency bands. For example, the sound amplitude can conform to a specific sound amplitude distribution in certain frequency bands.

[0119] Specifically, the previous scene type identifier of the scene type detected by the headphones is obtained, and the target detection frequency band is searched using the previous scene type identifier. If the signal amplitude change value of the first audio signal collected by the feedforward microphone in the target detection frequency band is greater than a preset change threshold, it can be considered that the scene type of the external scene where the headphones are located has changed, thereby triggering the execution of the above-mentioned step of determining the current scene type of the external scene where the headphones are located based on the first audio signal. If the signal amplitude change value of the first audio signal collected by the feedforward microphone in the target detection frequency band is not greater than the preset change threshold, it can be considered that the scene type of the external scene where the headphones are located has not changed, thereby directly determining the previously detected scene type as the current scene type of the external scene where the headphones are located. This approach enables the detection of the target frequency band based on the previously detected scene type. By monitoring the change in the sound amplitude of the first audio signal within the target detection frequency band, it is possible to indirectly detect whether the scene type of the external environment in which the headphones are located has changed. This determines whether to use the currently acquired first audio signal to check the current scene type. The entire detection process does not require re-detecting the scene type of the external environment every time. Instead, the scene type detection process is only triggered after a change in the scene type of the external environment in which the headphones are located is detected. This is not a real-time scene type detection process, thus reducing the power consumption of the headphones.

[0120] It should be understood that although the steps in the flowcharts of the embodiments described above are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the embodiments described above may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages of other steps.

[0121] Based on the same inventive concept, this application also provides an earphone control device for implementing the earphone control method described above. The solution provided by this device is similar to the implementation described in the above method; therefore, the specific limitations in one or more earphone control device embodiments provided below can be found in the limitations of the earphone control method described above, and will not be repeated here.

[0122] In one exemplary embodiment, such as Figure 3 As shown, a headphone control device is provided, including: a signal acquisition module 402, a signal acquisition module 404, a spectrum relationship information determination module 406, a parameter adjustment module 408, and an iterative loop module 410, wherein:

[0123] Signal acquisition module 402 is used to acquire a first audio signal through the feedforward microphone and a second audio signal through the feedback microphone;

[0124] The signal acquisition module 404 is used to determine the current scene type of the external scene where the headphones are located based on the first audio signal, and to acquire the target effect audio signal corresponding to the current scene type.

[0125] The spectrum relationship information determination module 406 is used to determine the current spectrum relationship information between the first audio signal and the second audio signal, and the target spectrum relationship information between the first audio signal and the target effect audio signal;

[0126] The parameter adjustment module 408 is used to adjust the filter parameters of the headphones according to the current spectrum relationship information and the target spectrum relationship information;

[0127] The signal acquisition module 402 is also used to acquire the second audio signal again according to the adjusted filter parameters;

[0128] The iterative loop module 410 is used to determine that the error between the second audio signal acquired again and the target effect audio signal is greater than or equal to a preset error, and then return to the steps of acquiring the first audio signal through the feedforward microphone and acquiring the second audio signal through the feedback microphone, until the error between the second audio signal acquired again and the target effect audio signal is less than the preset error.

[0129] In one embodiment, the signal acquisition module is further configured to:

[0130] Extract audio signal features from the first audio signal; determine the current scene type of the external scene in which the headphones are located based on the audio signal features.

[0131] In one embodiment, the signal acquisition module is further configured to:

[0132] The method obtains the scene type previously detected by the headphones and determines the target detection frequency band based on the previously detected scene type. If the change in the signal amplitude of the first audio signal in the target detection frequency band is greater than a preset change threshold, it is determined that the scene type of the external scene where the headphones are located has changed, and the step of determining the current scene type of the external scene where the headphones are located based on the first audio signal is executed. If the change in the signal amplitude of the first audio signal in the target detection frequency band is not greater than the preset change threshold, it is determined that the scene type of the external scene where the headphones are located has not changed, and the previously detected scene type is determined as the current scene type of the external scene where the headphones are located.

[0133] In one embodiment, the parameter adjustment module is further configured to:

[0134] The deviation between the current spectrum relationship information and the target spectrum relationship information is calculated to obtain the first spectrum deviation information; based on the preset transfer function and the first spectrum deviation information, the first parameter adjustment information corresponding to the filter parameters of the headphones is determined; based on the first parameter adjustment information, the filter parameters of the headphones are adjusted.

[0135] In one embodiment, the first parameter adjustment information includes the parameter adjustment magnitude and the parameter adjustment direction; the parameter adjustment module is further configured to:

[0136] Based on the first spectral deviation information, the signal amplitude deviation between the first audio signal and the second audio signal in each preset frequency band is determined; based on the signal amplitude deviation in each preset frequency band and the preset transfer function, the parameter adjustment magnitude and parameter adjustment direction of the headphone filter parameters in each preset frequency band are determined.

[0137] In one embodiment, the apparatus further includes:

[0138] The signal adjustment module is used to adjust the signal amplitude of the target effect audio signal in response to a first adjustment command; or to adjust the signal amplitude distribution of the target effect audio signal in each preset frequency band in response to a second adjustment command.

[0139] In one embodiment, the apparatus further includes:

[0140] The wearing status detection module is used to detect the wearing status of the headphones in real time; if the wearing status of the headphones changes, the step of determining the current spectrum relationship information between the first audio signal and the second audio signal, and the target spectrum relationship information between the first audio signal and the target effect audio signal is triggered.

[0141] In one embodiment, the target effect audio signal includes at least one of the following:

[0142] Full-band active noise cancellation for audio signals;

[0143] Full-band pass-through effect for audio signals;

[0144] The audio signals with active noise reduction effect in multiple first frequency bands and the audio signals with pass-through effect in multiple second frequency bands, wherein the multiple first frequency bands and the multiple second frequency bands constitute the full frequency band.

[0145] In one embodiment, the headphones are equipped with multiple feedforward microphones corresponding to multiple sound transmission directions, the first audio signal includes external sound signals from the multiple sound transmission directions, the current spectrum relationship information includes first spectrum relationship information corresponding to the external sound signals from the multiple sound transmission directions, and the target spectrum relationship information includes second spectrum relationship information corresponding to the external sound signals from the multiple sound transmission directions; the parameter adjustment module is further configured to:

[0146] The deviation between the first spectral relationship information and the second spectral relationship information in each of the sound transmission directions is calculated to obtain the second spectral deviation information in each of the sound transmission directions; based on the second spectral deviation information in each of the sound transmission directions, the second parameter adjustment information corresponding to the filter parameters of the headphones in each of the sound transmission directions is determined; based on the second parameter adjustment information, the filter parameters of the headphones in each of the sound transmission directions are adjusted.

[0147] Each module in the aforementioned headphone control device can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in the processor within the headphone in hardware form or independent of it, or stored in the headphone's memory in software form, so that the processor can call and execute the corresponding operations of each module.

[0148] In one exemplary embodiment, an earphone is provided, the internal structure of which can be shown in the diagram below. Figure 4 As shown, the headset includes a feedforward microphone, a feedback microphone, a processor, a memory, an input / output interface, a communication interface, a display unit, and an input device. The feedforward microphone is used to collect external sound signals, while the feedback microphone collects sound signals from the ear canal of the user. The processor, memory, and input / output interface are connected via a system bus, as are the communication interface, display unit, and input device. The headset's processor provides computing and control capabilities. The headset's memory includes a non-volatile storage medium and internal memory. The non-volatile storage medium stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage medium. The headset's input / output interface is used for exchanging information between the processor and external devices. The headset's communication interface is used for wired or wireless communication with external terminals; wireless communication can be achieved through Wi-Fi, mobile cellular networks, Near Field Communication (NFC), or other technologies. When the computer program is executed by the processor, it implements a headset control method.

[0149] Those skilled in the art will understand that Figure 4 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the headphones to which the present application is applied. Specific headphones may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0150] In one embodiment, an earphone is also provided, including a feedforward microphone, a feedback microphone, a memory, and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps in the above method embodiments.

[0151] In one embodiment, a computer-readable storage medium is provided having a computer program stored thereon that, when executed by a processor, implements the steps in the above method embodiments.

[0152] In one embodiment, a computer program product is provided, including a computer program that, when executed by a processor, implements the steps in the above method embodiments.

[0153] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile memory and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, artificial intelligence (AI) processors, etc., and are not limited to these.

[0154] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0155] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A headphone control method, characterized in that, Applied to headphones, the headphones including a feedforward microphone and a feedback microphone; the method includes: A first audio signal is acquired through the feedforward microphone and a second audio signal is acquired through the feedback microphone; Based on the first audio signal, determine the current scene type of the external scene where the headphones are located, and obtain the target effect audio signal corresponding to the current scene type; Determine the current spectral relationship information between the first audio signal and the second audio signal, and the target spectral relationship information between the first audio signal and the target effect audio signal; The filter parameters of the headphones are adjusted based on the current spectrum relationship information and the target spectrum relationship information. The second audio signal is acquired again based on the adjusted filter parameters; If it is determined that the error between the second audio signal acquired again and the target effect audio signal is greater than or equal to a preset error, then the process returns to the steps of acquiring the first audio signal through the feedforward microphone and acquiring the second audio signal through the feedback microphone, until the error between the second audio signal acquired again and the target effect audio signal is less than the preset error.

2. The method according to claim 1, characterized in that, The method further includes: Obtain the scene type previously detected by the earphone, and determine the target detection frequency band based on the previously detected scene type; If the change in the amplitude of the first audio signal in the target detection frequency band is greater than a preset change threshold, it is determined that the scene type of the external scene where the headphones are located has changed, and the step of determining the current scene type of the external scene where the headphones are located based on the first audio signal is executed. If the change in the amplitude of the first audio signal in the target detection frequency band is not greater than a preset change threshold, it is determined that the scene type of the external scene where the headphones are located has not changed, and the scene type detected last time is determined as the current scene type of the external scene where the headphones are located.

3. The method according to claim 1, characterized in that, The step of determining the current scene type of the external environment in which the headphones are located based on the first audio signal includes: Extract audio signal features from the first audio signal; The current scene type of the external scene in which the headphones are located is determined based on the characteristics of the audio signal.

4. The method according to claim 1, characterized in that, The step of adjusting the filter parameters of the headphones based on the current spectrum relationship information and the target spectrum relationship information includes: Calculate the deviation between the current spectrum relationship information and the target spectrum relationship information to obtain the first spectrum deviation information; Based on the preset transfer function and the first spectral deviation information, the first parameter adjustment information corresponding to the filter parameters of the headphones is determined; The filter parameters of the headphones are adjusted based on the first parameter adjustment information.

5. The method according to claim 4, characterized in that, The first parameter adjustment information includes the parameter adjustment magnitude and parameter adjustment direction; the step of determining the first parameter adjustment information corresponding to the filter parameters of the headphones based on the preset transfer function and the first spectral deviation information includes: Based on the first spectral deviation information, the signal amplitude deviation between the first audio signal and the second audio signal in each preset frequency band is determined; Based on the signal amplitude deviation and preset transfer function under each preset frequency band, the adjustment range and direction of the headphone filter parameters under each preset frequency band are determined.

6. The method according to claim 1, characterized in that, The method further includes: In response to the first adjustment command, the signal amplitude of the target effect audio signal is adjusted; Alternatively, in response to a second adjustment command, the signal amplitude distribution of the target effect audio signal in each preset frequency band can be adjusted.

7. The method according to claim 1, characterized in that, The method further includes: Real-time detection of the wearing status of the headphones; If the wearing status of the headphones changes, the step of determining the current spectral relationship information between the first audio signal and the second audio signal, and the target spectral relationship information between the first audio signal and the target effect audio signal is triggered.

8. The method according to claim 1, characterized in that, The target effect audio signal includes at least one of the following: Full-band active noise cancellation for audio signals; Full-band pass-through effect for audio signals; The audio signals with active noise reduction effect in multiple first frequency bands and the audio signals with pass-through effect in multiple second frequency bands, wherein the multiple first frequency bands and the multiple second frequency bands constitute the full frequency band.

9. The method according to claim 1, characterized in that, The headphones are equipped with multiple feedforward microphones corresponding to multiple sound transmission directions. The first audio signal includes external sound signals from the multiple sound transmission directions. The current spectrum relationship information includes first spectrum relationship information corresponding to the external sound signals from the multiple sound transmission directions. The target spectrum relationship information includes second spectrum relationship information corresponding to the external sound signals from the multiple sound transmission directions. The step of adjusting the filter parameters of the headphones based on the current spectrum relationship information and the target spectrum relationship information includes: Calculate the deviation between the first spectral relationship information and the second spectral relationship information in each of the sound transmission directions to obtain the second spectral deviation information in each of the sound transmission directions; Based on the second spectral deviation information in each of the sound transmission directions, the second parameter adjustment information corresponding to the filter parameters of the headphones in each of the sound transmission directions is determined respectively; Based on the adjustment information of each of the second parameters, the filter parameters of the headphones are adjusted in each of the sound transmission directions.

10. An earphone, comprising a feedforward microphone, a feedback microphone, a memory, and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 9.

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