Instability detection method and system, active noise reduction system and control method thereof

Abstract

The present disclosure provides a method and system for detecting instability, an active noise reduction system and a control method thereof. The method for detecting instability is applied to an active noise reduction system, the active noise reduction system comprising a speaker and a reference microphone. The method for detecting instability comprises: obtaining a first acoustic feedback energy and a first total energy of a first sound signal collected by the reference microphone; and determining that the active noise reduction system is unstable in response to the first acoustic feedback energy and the first total energy meeting an instability condition. The present disclosure determines that the active noise reduction system is unstable by meeting the instability condition that the first acoustic feedback energy and the first total energy meet. By calculating the first proportion and the first difference, the interference of abnormal sound from the external environment can be effectively offset, thereby avoiding the phenomenon of false judgment of the active noise reduction system being unstable. Therefore, the method for detecting instability can more accurately determine whether the active noise reduction system is in an unstable state.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of active noise reduction, in particular to a method and system for detecting instability, an active noise reduction system and a control method thereof. BACKGROUND

[0002] An active noise reduction system generally comprises a reference microphone, a speaker and a controller. The working principle is that the sound signal obtained by the reference microphone is input into the controller to calculate the control signal of the sound signal, and the control signal is output through the speaker to make the control signal and the sound signal cancel out, thereby achieving the effect of noise reduction.

[0003] For an active noise reduction system, stability is an important evaluation index. In order to avoid instability of the active noise reduction system, the instability detection method generally detects the stability of the active noise reduction system, and takes corresponding measures when the active noise reduction system is detected to be unstable.

[0004] The commonly used instability detection method is to detect whether the output power of the control signal output by the speaker exceeds a threshold value. If it exceeds, it is determined that the instability detection system is unstable. However, when there is an abnormal sound such as the collision sound of cooking in the external environment, the reference microphone will also obtain the sound signal, and the output power of the control signal of the speaker calculated based on the sound signal obtained by the reference microphone will increase to exceed the threshold value, resulting in instability misjudgment. SUMMARY

[0005] The technical problem to be solved by the present disclosure is to overcome the defect that the instability detection method in the prior art is disturbed by the external environment, resulting in instability misjudgment, and to provide an instability detection method and system, and a control method and system of an active noise reduction system.

[0006] The present disclosure solves the above technical problems by the following technical solutions:

[0007] In a first aspect, an instability detection method is improved, which is applied to an active noise reduction system; the active noise reduction system comprises a speaker and a reference microphone; the instability detection method comprises:

[0008] obtaining a first sound feedback energy and a first total energy of a first sound signal collected by the reference microphone; wherein the first sound feedback energy is obtained according to a first control signal of the speaker and a sound feedback path;

[0009] determining that the active noise reduction system is unstable in response to the first acoustic feedback energy and the first total energy meeting an instability condition; wherein the instability condition comprises at least one of: a first ratio of the first acoustic feedback energy to the first total energy being greater than or equal to a ratio threshold, a first difference of the first total energy to the first acoustic feedback energy being less than or equal to a difference threshold, the first ratio being less than the ratio threshold and gradually increasing, the first difference being less than the difference threshold and gradually increasing.

[0010] Optionally, the step of determining the ratio threshold comprises:

[0011] obtaining a second acoustic feedback energy and a second total energy of a second sound signal collected by the reference microphone when the active noise reduction system is not unstable, to calculate a second ratio of the second acoustic feedback energy to the second total energy; wherein the second acoustic feedback energy is obtained according to a second control signal of the loudspeaker and the acoustic feedback path;

[0012] adjusting the gain of the acoustic feedback path to simulate the active noise reduction system being unstable, obtaining a third acoustic feedback energy and a third total energy of a third sound signal collected by the reference microphone, to calculate a third ratio of the third acoustic feedback energy to the third total energy; wherein the third acoustic feedback energy is obtained according to a third control signal of the loudspeaker and the acoustic feedback path;

[0013] selecting the ratio threshold within a numerical interval of the second ratio to the third ratio;

[0014] and / or,

[0015] the step of determining the difference threshold comprises:

[0016] obtaining a second acoustic feedback energy and a second total energy of a second sound signal collected by the reference microphone when the active noise reduction system is not unstable, to calculate a second difference of the second acoustic feedback energy in the second total energy; wherein the second acoustic feedback energy is obtained according to a second control signal of the loudspeaker and the acoustic feedback path;

[0017] adjusting the gain of the acoustic feedback path to simulate the active noise reduction system being unstable, obtaining a third acoustic feedback energy and a third total energy of a third sound signal collected by the reference microphone, to calculate a third difference of the third acoustic feedback energy in the third total energy; wherein the third acoustic feedback energy is obtained according to a third control signal of the loudspeaker and the acoustic feedback path;

[0018] selecting the difference threshold within a numerical interval of the second difference to the third difference.

[0019] Optionally, the adjusting the gain of the acoustic feedback path to simulate the instability of the active noise reduction system comprises:

[0020] decreasing the gain in a polling manner and in a decreasing step until the active noise reduction system is unstable.

[0021] Optionally, the determining the instability of the active noise reduction system in response to the first acoustic feedback energy and the first total energy meeting an instability condition comprises:

[0022] the determining the final instability of the active noise reduction system in response to the first acoustic feedback energy and the first total energy meeting the instability condition for a plurality of times.

[0023] In a second aspect, a control method of an active noise reduction system is provided, and the control method comprises:

[0024] In a case where the instability detection method according to any one of the preceding aspects determines that the active noise reduction system is unstable, restarting the active noise reduction system.

[0025] Optionally, the active noise reduction system further comprises a controller, and the controller is configured to convert a sound signal into a control signal; and the restarting the active noise reduction system comprises:

[0026] acquiring a continuous instability frequency of the active noise reduction system;

[0027] in response to the continuous instability frequency being greater than or equal to a frequency threshold, shutting down the active noise reduction system and optimizing the controller; and after the active noise reduction system is restarted, performing active noise reduction based on the optimized controller.

[0028] In a third aspect, an instability detection system is provided, and the instability detection system is configured to implement the instability detection method according to any one of the preceding aspects; and the detection system comprises:

[0029] an acquisition module configured to acquire a first acoustic feedback energy and a first total energy of a first sound signal collected by a reference microphone; wherein the first acoustic feedback energy is obtained according to a first control signal of a loudspeaker and an acoustic feedback path;

[0030] a response module configured to determine the instability of the active noise reduction system in response to the first acoustic feedback energy and the first total energy meeting an instability condition; wherein the instability condition comprises at least one of the following: a first ratio of the first acoustic feedback energy to the first total energy being greater than or equal to a ratio threshold, a first difference of the first total energy to the first acoustic feedback energy being less than or equal to a difference threshold, the first ratio being less than the ratio threshold and gradually increasing, and the first difference being less than the difference threshold and gradually increasing.

[0031] In a fourth aspect, provided is an active noise reduction system, characterized by being used to implement the control method of any one of the preceding aspects; the control system comprises:

[0032] a detection module, configured to call a restart module when it is determined according to the instability detection method of any one of the preceding aspects that the active noise reduction system is unstable;

[0033] a restart module, configured to restart the active noise reduction system.

[0034] In a fifth aspect, provided is a household appliance, comprising a memory, a processor, and a computer program stored in the memory and used to run on the processor, characterized by that the processor implements the instability detection method of any one of the preceding aspects or the control method of the active noise reduction system of any one of the preceding aspects when the computer program is executed.

[0035] In a sixth aspect, provided is a computer readable storage medium, which stores a computer program, characterized by that the computer program is executed by a processor to implement the instability detection method of any one of the preceding aspects or the control method of the active noise reduction system of any one of the preceding aspects.

[0036] On the basis of common sense in the art, the preferred conditions described above can be combined in any manner, thereby obtaining preferred examples of the present disclosure.

[0037] The positive progress effect of the present disclosure is that the present disclosure determines that the active noise reduction system is unstable by satisfying the condition that the first acoustic feedback energy and the first total energy meet the instability condition. By calculating the first proportion and the first difference, the interference of abnormal sound from the external environment can be effectively offset, thereby avoiding the phenomenon of false judgment of instability of the active noise reduction system, and thus the instability detection method can more accurately determine whether the active noise reduction system is in an unstable state. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 A frequency domain signal curve diagram for stabilizing single-frequency abnormal sound, howling, and normal noise is provided for an exemplary embodiment of the present disclosure;

[0039] Figure 2 A time domain signal curve diagram for stabilizing single-frequency abnormal sound, howling, and normal noise is provided for an exemplary embodiment of the present disclosure;

[0040] Figure 3 A flowchart of an instability detection method is provided for an exemplary embodiment of the present disclosure;

[0041] Figure 4 A flowchart of determining a ratio threshold in an instability detection method is provided for an exemplary embodiment of the present disclosure;

[0042] Figure 5 A flow chart of another instability detection method provided for an exemplary embodiment of the present disclosure;

[0043] Figure 6 A flow chart of a control method of an active noise reduction system provided for an exemplary embodiment of the present disclosure;

[0044] Figure 7 A module schematic diagram of an instability detection system provided for an exemplary embodiment of the present disclosure;

[0045] Figure 8 A module schematic diagram of an active noise reduction system provided for an exemplary embodiment of the present disclosure;

[0046] Figure 9 A structure schematic diagram of a household appliance shown for an exemplary embodiment of the present disclosure. DETAILED DESCRIPTION

[0047] The present disclosure will be further described below by way of examples, but the present disclosure is not limited to the examples.

[0048] The prefix words such as “first”, “second” are used in the embodiments of the present disclosure only for distinguishing different described objects, and have no limiting effect on the position, order, priority, number or content of the described objects. The use of the ordinal words in the embodiments of the present disclosure for distinguishing the described objects does not constitute limitation on the described objects, and the statement of the described objects should refer to the description in the context of the claims or embodiments, and should not constitute redundant limitation because of the use of the prefix words. In addition, in the description of the embodiments, unless otherwise specified, the meaning of “plurality” is two or more than two.

[0049] Instability detection of the active noise reduction system is that, when the active noise reduction system works, due to some faults or interference, an abnormal sound is emitted by the loudspeaker of the active noise reduction system, which affects the user experience. The abnormal sound includes howling and stable single-frequency abnormal sound (or stable single-frequency sound). The instability detection method provided in the embodiments can realize the detection of howling and the detection of stable single-frequency abnormal sound.

[0050] The characteristics of howling of the active noise reduction system are as follows: referring to Figure 1 and Figure 2 There is a prominent peak on the noise spectrum, the amplitude of the highest point of the peak is significantly higher than the adjacent frequency, and the peak value is generally much larger than the peak value of the stable single-frequency abnormal sound, and accounts for a large proportion of the overall noise power. The power amplitude of howling in the time domain gradually increases from small to large from the beginning of generation, and the ratio of the maximum power to the minimum power generally exceeds 5 times or more, and the amplitude generally approaches or even exceeds the maximum sound power of the loudspeaker itself. Figure 1The second to fifth columns of the table refer to the amplitude values ​​at 94.28Hz, 108.75Hz, 0Hz, and 6000Hz, respectively. The sixth column, RMS data, refers to the root mean square amplitude values ​​from 0 to 6000Hz. Amplitude can be characterized by, but is not limited to, power, energy, and decibels.

[0051] Unlike howling, stable single-frequency abnormal noise / stable single-frequency sound is characterized by a prominent peak in the noise spectrum. The amplitude of the peak (noise peak value) is higher than the amplitude of the corresponding adjacent frequency, and the power of this peak accounts for a relatively small proportion of the total noise power. That is, the power of the peak accounts for a proportion of the total noise power that is less than or equal to the power threshold, where the power threshold is determined based on experimental data. Figure 1 As shown by the blue curve, the bandwidth of this peak does not exceed 50Hz. See also Figure 2 In stable single-frequency noise, the power amplitude in the time domain is relatively stable from the beginning of its generation, with little power variation. The ratio of the maximum power to the minimum power will not exceed 3 times, and the amplitude is generally much smaller than the maximum sound power of the speaker itself. Figure 2 The left vertical axis represents the power amplitude, and the right vertical axis represents the sound pressure amplitude; the two can be converted to each other.

[0052] To reduce the false positive rate of instability in active noise cancellation systems, an exemplary embodiment of the present invention provides an instability detection method. Figure 3 This flowchart illustrates an instability detection method provided in an exemplary embodiment of this disclosure, applied to an active noise cancellation system. The active noise cancellation system includes at least a reference microphone, a speaker, and a controller. The reference microphone is deployed near the noise source of the device equipped with the active noise cancellation system. The reference microphone is used to acquire sound signals. These sound signals are filtered by a calibrated controller to obtain a control signal, which is then played through the speaker for active noise cancellation. It should be noted that the specific implementation of the controller's calibration method is described in relevant technical descriptions and will not be repeated here.

[0053] It should be noted that, in addition to range hoods, this active noise reduction system can also be used to reduce noise in other home appliances such as dishwashers, refrigerators, washing machines, dryers, blenders, juicers, kitchen fans, and coffee machines. The instability detection method includes the following steps:

[0054] Step 101: Obtain the first total energy of the first sound feedback energy and the first sound signal collected by the reference microphone.

[0055] The first acoustic feedback energy is obtained based on the loudspeaker's first control signal and the acoustic feedback path. The acoustic feedback path can be obtained based on Wiener filter calibration; for details, please refer to the relevant technical description, which will not be elaborated here.

[0056] Furthermore, the formula for calculating the energy of the first sound feedback is:

[0057]

[0058] wherein, is a first acoustic feedback energy, is a first control signal of the loudspeaker, is an acoustic feedback path, is a total number of sampling points of the first control signal.

[0059] The calculation formula of the first total energy is:

[0060]

[0061] wherein, is the first total energy, is a first sound signal collected by the reference microphone, is a total number of sampling points of the first sound signal.

[0062] Step 102, in response to the first acoustic feedback energy and the first total energy meeting an instability condition, determining that the active noise reduction system is unstable.

[0063] wherein, the instability condition comprises at least one of the following: a first ratio of the first acoustic feedback energy to the first total energy is greater than or equal to a ratio threshold, a first difference of the first total energy to the first acoustic feedback energy is less than or equal to a difference threshold, the first ratio is less than the ratio threshold and gradually increases, and the first difference is less than the difference threshold and gradually increases.

[0064] Further, the calculation formula of the first ratio is:

[0065]

[0066] wherein, is the first ratio, is the first total energy, is the first acoustic feedback energy. When the reference microphone also receives the abnormal sound (such as the sound of cutting vegetables) generated by the outside world, the sound signal obtained by the reference microphone will become larger, and the control signal obtained after the controller processes the sound signal will also increase, so the control signal output by the loudspeaker will also become larger. Because the sound signal and the control signal are both larger, the total energy and the acoustic feedback energy will also become larger, and by calculating the ratio of the acoustic feedback energy and the total energy, a part of the acoustic feedback energy can be offset. Therefore, by calculating the ratio, the interference of a part of the abnormal sound can be offset, and the accuracy of the detection method is higher.

[0067] The calculation formula of the first difference is:

[0068]

[0069] wherein, is the first difference, is the first total energy, is the first acoustic feedback energy.

[0070] When the reference microphone receives the abnormal sound (for example, the sound of cutting vegetables) from the outside world, the sound signal obtained by the reference microphone will become larger, and the control signal obtained by processing the sound signal by the controller will also become larger, so the control signal output by the loudspeaker will also become larger. Because the sound signal and the control signal are both larger, the total energy and the acoustic feedback energy will also become larger, and when the difference between the acoustic feedback energy and the total energy is calculated, part of the acoustic feedback energy can be offset. Therefore, by calculating the difference, the interference of part of the abnormal sound can be offset, and the accuracy of the detection method is higher.

[0071] In this embodiment, the present disclosure determines that the active noise reduction system is unstable by satisfying that the first acoustic feedback energy and the first total energy meet the instability condition. By calculating the first ratio and the first difference, the interference of the abnormal sound from the outside environment can be effectively offset, and the phenomenon of false judgment of the active noise reduction system instability can be avoided, so that the instability detection method can more accurately determine whether the active noise reduction system is in an unstable state.

[0072] In one embodiment, the step of determining the ratio threshold value comprises:

[0073] S1: When the active noise reduction system is not unstable, the second acoustic feedback energy and the second total energy of the second sound signal collected by the reference microphone are obtained to calculate the second ratio of the second acoustic feedback energy in the second total energy.

[0074] Preferably, the maximum value of the ratio of the second acoustic feedback energy to the second total energy when the active noise reduction system is not unstable is selected as the second ratio.

[0075] wherein, the second acoustic feedback energy is obtained according to the second control signal of the loudspeaker and the acoustic feedback path.

[0076] S2: Adjust the gain of the acoustic feedback path to simulate the active noise reduction system after being unstable, obtain the third acoustic feedback energy and the third total energy of the third sound signal collected by the reference microphone, and calculate the third ratio of the third acoustic feedback energy to the third total energy.

[0077] S3: Select the ratio threshold value in the numerical interval of the second ratio to the third ratio.

[0078] In the embodiment, if the ratio threshold is set lower than the second ratio, the active noise reduction system can be too conservative to achieve a good noise reduction effect; if set too high, the active noise reduction system can be unstable. Therefore, selecting the ratio threshold in the numerical interval of the second ratio to the third ratio can make the active noise reduction system maintain stability while exerting its noise reduction performance as much as possible to improve the user experience. In addition, by setting a suitable ratio threshold, preventive measures can be taken when the active noise reduction system is likely to be unstable to prevent the active noise reduction system from being unstable in advance.

[0079] It should be noted that step S1 can be performed before the active noise reduction system is shipped, that is, the second ratio is determined through experiments, so as to ensure that the active noise reduction system is in a non-unstable state and there is no environmental noise interference when the second ratio is determined, thereby improving the accuracy of the determination of the second ratio and the accuracy of the determination of the ratio threshold.

[0080] Steps S2 and S3 can be performed before the active noise reduction system is shipped or after it is put into use. Performing after it is put into use can make the determination of the third ratio conform to the use scenario of the active noise reduction system, and can avoid affecting the accuracy of the ratio threshold due to the pollution of the feedback path caused by oil or other reasons, and the mismatch between the determined third ratio and the use scenario of the active noise reduction system.

[0081] In one embodiment, the step of determining the difference threshold comprises:

[0082] S1: When the active noise reduction system is not unstable, the second sound feedback energy and the second total energy of the second sound signal collected by the reference microphone are obtained to calculate a second difference value of the second sound feedback energy in the second total energy.

[0083] Preferably, the interpolation minimum value of the second sound feedback energy in the second total energy when the active noise reduction system is not unstable can be selected as the second difference value.

[0084] Wherein, the second sound feedback energy is obtained according to the second control signal of the loudspeaker and the sound feedback path.

[0085] S2: Adjust the gain of the sound feedback path to simulate the active noise reduction system after being unstable, obtain the third sound feedback energy and the third total energy of the third sound signal collected by the reference microphone, and calculate the third difference value of the third sound feedback energy in the third total energy.

[0086] Wherein, the third sound feedback energy is obtained according to the third control signal of the loudspeaker and the sound feedback path;

[0087] S3: Select the difference threshold in the numerical interval of the second difference value to the third difference value.

[0088] In the embodiment, if the difference threshold is set lower than the second difference, the active noise reduction system can be too conservative to achieve a good noise reduction effect; if set too high, the active noise reduction system can be unstable. Therefore, selecting the difference threshold in the numerical interval of the second difference to the third difference can make the active noise reduction system maintain stability while exerting its noise reduction performance as much as possible to improve the user experience. In addition, by setting a suitable difference threshold, preventive measures can be taken when the active noise reduction system is likely to be unstable to prevent the active noise reduction system from being unstable.

[0089] In one embodiment, adjusting the gain of the acoustic feedback path to simulate instability of the active noise reduction system comprises:

[0090] The gain is reduced in a polling manner and in decreasing steps until the active noise reduction system is unstable.

[0091] Specifically, only the reduction of the gain of the acoustic feedback path can trigger the instability of the active noise reduction system, because when the gain of the acoustic feedback path becomes smaller, the required acoustic feedback energy to be removed decreases, and the actual noise obtained by the reference microphone becomes larger, and the control signal calculated by the controller becomes larger, so it is likely to make the control signal emitted by the loudspeaker larger and cause the instability of the active noise reduction system.

[0092] At present, due to the limitation of the layout and structure of various smoke machines, the acoustic feedback path is affected by many factors such as external space, so it is difficult to quantify its gain, and the best way is to reduce the gain in a polling manner. The method can be: first, set the gain; second, calculate the ratio of the acoustic feedback energy to the total energy; third, judge whether there is instability phenomenon (whether the noise is raised), if not, reduce the gain by a step, and repeat the above three steps until the active noise reduction system is unstable to obtain the third ratio.

[0093] It should be noted that the step can be a fixed value or a dynamic value; when the step is a dynamic value, the step is positively correlated with the third ratio, or the step is positively correlated with the third difference.

[0094] In the embodiment, by polling and reducing the gain in decreasing steps, the third ratio can be found more quickly and accurately. For example, the preset acoustic feedback path gain is 1.0, and when the ratio is the third ratio, the corresponding acoustic feedback path target gain is 0.5. If a more accurate target gain is required, the step can be set to 0.25, 0.15, and 0.1 when polling, so that the target gain can be adjusted to the target gain only by polling three times. Compared with setting a fixed step, for example, 0.1, the target gain needs to be adjusted by polling five times.

[0095] Figure 3A flow chart for determining the ratio threshold in the instability detection method provided for an exemplary embodiment of the present disclosure is provided below, taking the determination of the ratio threshold before the active noise reduction system leaves the factory as an example, to further illustrate how to determine the ratio threshold, see Figure 2 .

[0096] S1: Calibrate the controller under the condition that the reference microphone and the loudspeaker are determined before leaving the factory.

[0097] S2: Obtain the second ratio under the condition that the active noise reduction system is not unstable, and obtain the third ratio under the condition that the active noise reduction system is unstable.

[0098] S3: Select the ratio threshold in the numerical interval of the second ratio to the third ratio.

[0099] In one embodiment, in response to the first acoustic feedback energy and the first total energy meeting the instability condition, comprising:

[0100] In response to the first acoustic feedback energy and the first total energy obtained multiple times meeting the instability condition, it is determined that the active noise reduction system is unstable.

[0101] In this embodiment, by the first acoustic feedback energy and the first total energy obtained multiple times meeting the instability condition, the situation of false judgment of the active noise reduction system being unstable due to abnormal increase of sound can be avoided, and the accuracy of the instability detection method is improved.

[0102] In one embodiment, Figure 4 A flow chart of another instability detection method provided for an exemplary embodiment of the present disclosure is provided, in combination with Figure 4 , to further illustrate the instability detection method.

[0103] S1: Obtain the sound signal obtained by the reference microphone.

[0104] S2: Obtain the control signal output by the loudspeaker.

[0105] S3: Calculate the ratio of the acoustic feedback energy and the total energy according to the control signal, the acoustic feedback path, and the sound signal.

[0106] S4: Determine whether the ratio reaches the ratio threshold, if yes, go to S6, if not, go to S5.

[0107] S5: Determine whether the ratio obtained multiple times is all increased, if yes, go to S6, if not, go to S2.

[0108] S6: Determine that the active noise reduction system is unstable.

[0109] An exemplary embodiment of the present disclosure provides a control method of an active noise reduction system. Figure 6A flow chart of a control method of an active noise reduction system is provided for an exemplary embodiment of the present disclosure. The control method comprises:

[0110] Step 201: determining whether the active noise reduction system is unstable according to the above instability detection method.

[0111] In step 202, if the determination result is yes, the active noise reduction system is restarted.

[0112] In this embodiment, the active noise reduction system is restarted when it is unstable, which can eliminate temporary errors or abnormal conditions that may cause instability to some extent, so as to restore the active noise reduction system to a stable state, thereby avoiding its howling. This can improve the user's experience.

[0113] In one embodiment, the active noise reduction system further comprises a controller for converting a sound signal into a control signal. Restarting the active noise reduction system comprises:

[0114] S1: obtaining the number of consecutive instabilities of the active noise reduction system.

[0115] S2: in response to the number of consecutive instabilities being greater than or equal to a number threshold, shutting down the active noise reduction system and optimizing the controller; after restarting, the active noise reduction system performs active noise reduction based on the optimized controller. Preferably, the number threshold is set to 10 times.

[0116] The controller can be optimized by LMS algorithm (least mean square algorithm). It should be noted that the labeling method of the controller is described in the related art, which will not be described here.

[0117] Further, in response to the number of consecutive instabilities being less than the number threshold, the active noise reduction system is directly restarted. If the active noise reduction system is not unstable after restarting, the number of consecutive instabilities is cleared. If the active noise reduction system is still unstable after restarting, the number of consecutive instabilities is incremented by 1 and the S1 step is performed again.

[0118] In this embodiment, when the number of consecutive instabilities is greater than or equal to the number threshold, it indicates that the controller is not matched. During the shutdown of the active noise reduction system, the controller is optimized in time to improve the stability and noise reduction effect of the active noise reduction system, thereby reducing user dissatisfaction and negative evaluation of the system.

[0119] Corresponding to the above instability detection method embodiment, the present disclosure also provides an instability detection system embodiment.

[0120] Figure 7 A module schematic diagram of an instability detection system is provided for an exemplary embodiment of the present disclosure. The detection system is applied to an active noise reduction system. The active noise reduction system comprises a loudspeaker and a reference microphone. The detection system comprises:

[0121] The acquisition module 71 is configured to acquire a first acoustic feedback energy and a first total energy of a first sound signal collected by a reference microphone, wherein the first acoustic feedback energy is obtained according to a first control signal of a loudspeaker and an acoustic feedback path.

[0122] The response module 72 is configured to determine that the active noise reduction system is unstable in response to the first acoustic feedback energy and the first total energy meeting an instability condition, wherein the instability condition comprises at least one of the following: a first ratio of the first acoustic feedback energy to the first total energy being greater than or equal to a ratio threshold, a first difference of the first total energy to the first acoustic feedback energy being less than or equal to a difference threshold, the first ratio being less than the ratio threshold and gradually increasing, and the first difference being less than the difference threshold and gradually increasing.

[0123] Optionally, the response module 72 comprises:

[0124] The first calculation unit is configured to, when the active noise reduction system is not unstable, acquire a second acoustic feedback energy and a second total energy of a second sound signal collected by the reference microphone, to calculate a second ratio of the second acoustic feedback energy in the second total energy, wherein the second acoustic feedback energy is obtained according to a second control signal of the loudspeaker and the acoustic feedback path.

[0125] The second calculation unit is configured to, after adjusting a gain of the acoustic feedback path to simulate that the active noise reduction system is unstable, acquire a third acoustic feedback energy and a third total energy of a third sound signal collected by the reference microphone, to calculate a third ratio of the third acoustic feedback energy in the third total energy, wherein the third acoustic feedback energy is obtained according to a third control signal of the loudspeaker and the acoustic feedback path.

[0126] The first selection unit is configured to select the ratio threshold in a numerical interval of the second ratio to the third ratio.

[0127] Optionally, the response module 72 comprises:

[0128] The third calculation unit is configured to, when the active noise reduction system is not unstable, acquire a second acoustic feedback energy and a second total energy of a second sound signal collected by the reference microphone, to calculate a second difference of the second acoustic feedback energy in the second total energy, wherein the second acoustic feedback energy is obtained according to a second control signal of the loudspeaker and the acoustic feedback path.

[0129] The fourth calculation unit is configured to, after adjusting a gain of the acoustic feedback path to simulate that the active noise reduction system is unstable, acquire a third acoustic feedback energy and a third total energy of a third sound signal collected by the reference microphone, to calculate a third difference of the third acoustic feedback energy in the third total energy, wherein the third acoustic feedback energy is obtained according to a third control signal of the loudspeaker and the acoustic feedback path.

[0130] The second selecting unit is configured to select the difference threshold value in a numerical interval of the second difference value to the third difference value.

[0131] Optionally, the third calculating unit and / or the fourth calculating unit comprise:

[0132] The polling component is configured to decrease the gain in a polling manner and with a decreasing step until the active noise reduction system is unstable.

[0133] Optionally, the response module 72 comprises:

[0134] The determining unit is configured to determine that the active noise reduction system is finally unstable in response to the first sound feedback energy and the first total energy acquired for multiple times both satisfying the instability condition.

[0135] Corresponding to the foregoing embodiment of the method for controlling the active noise reduction system, the disclosure also provides an embodiment of a control system for the active noise reduction system. Figure 8 A module schematic diagram of a control system for an active noise reduction system is provided for an exemplary embodiment of the disclosure, and the control system comprises:

[0136] The detection module 81 is configured to determine whether the active noise reduction system is unstable according to the foregoing instability detection method.

[0137] The restart module 82 is configured to restart the active noise reduction system.

[0138] Optionally, the active noise reduction system further comprises a controller, and the controller is configured to convert the sound signal into a control signal; the detection module 81 comprises:

[0139] The acquisition unit is configured to acquire the number of consecutive instabilities of the active noise reduction system;

[0140] The response unit is configured to, in response to the number of consecutive instabilities being greater than or equal to the number threshold value, close the active noise reduction system and optimize the controller; so that the active noise reduction system after being restarted performs active noise reduction based on the optimized controller.

[0141] For the system embodiment, since it basically corresponds to the method embodiment, the related parts can be referred to the part of the description of the method embodiment. The system embodiment described above is only illustrative, wherein the units described as separate components can be or can not be physically separated, and the components of the unit can be or can not be physical units, i.e., can be located in one place, or can be distributed on multiple network units. According to the actual needs, part or all of the modules can be selected to achieve the purpose of the disclosure scheme.

[0142] Figure 9This is a schematic diagram of the structure of a home appliance according to an example embodiment of the present disclosure. The home appliance includes a memory, a processor, and a computer program stored in the memory and used to run on the processor. When the processor executes the computer program, it implements the instability detection method or the control method of the active noise cancellation system provided in any of the above embodiments. Figure 9 The home appliance 90 shown is merely an example and should not impose any limitation on the functionality and scope of use of the embodiments disclosed herein.

[0143] like Figure 9 As shown, the home appliance 90 can be represented in the form of a general-purpose computing device, such as a server device. The components of the home appliance 90 may include, but are not limited to: at least one processor 91, at least one memory 92, and a bus 93 connecting different system components (including memory 92 and processor 91).

[0144] Bus 93 includes a data bus, an address bus, and a control bus.

[0145] The memory 92 may include volatile memory, such as random access memory (RAM) 921 and / or cache memory 922, and may further include read-only memory (ROM) 923.

[0146] The memory 92 may also include a program tool 925 (or utility) having a set (at least one) program module 924, such program module 924 including but not limited to: an operating system, one or more application programs, other program modules, and program data, each or some combination of these examples may include an implementation of a network environment.

[0147] The processor 91 executes various functional applications and data processing by running computer programs stored in the memory 92, such as the instability detection method or the control method of the active noise reduction system provided in any of the above embodiments.

[0148] The home appliance 90 can also communicate with one or more external devices 94 (e.g., keyboard, pointing device, etc.). This communication can be performed through the input / output (I / O) interface 95. Furthermore, the home appliance 90 can also communicate with one or more networks (e.g., local area network (LAN), wide area network (WAN), and / or public networks, such as the Internet) via a network adapter 96. As shown, the network adapter 96 communicates with other modules of the home appliance 90 via bus 93. It should be understood that, although not shown in the figure, other hardware and / or software modules can be used in conjunction with the home appliance 90, including but not limited to: microcode, device drivers, redundant processors, external disk drive arrays, RAID (disk array) systems, tape drives, and data backup storage systems.

[0149] It should be noted that, although several units / modules or sub-units / modules of the home appliance are mentioned in the above detailed description, such division is merely exemplary and not mandatory. Indeed, according to embodiments of the present disclosure, features and functions of two or more units / modules described above can be embodied in one unit / module. Conversely, features and functions of one unit / module described above can be further divided into embodied by a plurality of units / modules.

[0150] The embodiments of the present disclosure further provide a computer readable storage medium having stored thereon a computer program, which, when executed by a processor, implements the instability detection method or the control method of the active noise reduction system according to any of the above embodiments.

[0151] More specifically, the readable storage medium can include, but is not limited to, a portable disc, a hard disk, a random access memory, a read-only memory, an erasable programmable read-only memory, an optical storage device, a magnetic storage device, or any suitable combination of the above.

[0152] Although the specific embodiments of the present disclosure are described above, those skilled in the art should understand that this is only an illustration, and the protection scope of the present disclosure is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present disclosure, and such changes and modifications all fall within the protection scope of the present disclosure.

Claims

1. A method of detecting instability, characterized by, The instability detection method is applied to an active noise reduction system; The active noise reduction system comprises a speaker and a reference microphone; the instability detection method comprises: obtaining a first acoustic feedback energy and a first total energy of a first sound signal collected by the reference microphone; wherein the first acoustic feedback energy is obtained according to a first control signal of the speaker and an acoustic feedback path; in response to the first acoustic feedback energy and the first total energy meeting an instability condition, determining that the active noise reduction system is unstable; wherein the instability condition comprises at least one of the following: a first ratio of the first acoustic feedback energy to the first total energy is greater than or equal to a ratio threshold, a first difference of the first total energy to the first acoustic feedback energy is less than or equal to a difference threshold, the first ratio is less than the ratio threshold and gradually increases, and the first difference is less than the difference threshold and gradually increases; the step of determining the ratio threshold comprises: when the active noise reduction system is not unstable, obtaining a second acoustic feedback energy and a second total energy of a second sound signal collected by the reference microphone to calculate a second ratio of the second acoustic feedback energy to the second total energy; wherein the second acoustic feedback energy is obtained according to a second control signal of the speaker and the acoustic feedback path; adjusting the gain of the acoustic feedback path to simulate the instability of the active noise reduction system, obtaining a third acoustic feedback energy and a third total energy of a third sound signal collected by the reference microphone to calculate a third ratio of the third acoustic feedback energy to the third total energy; wherein the third acoustic feedback energy is obtained according to a third control signal of the speaker and the acoustic feedback path; selecting the ratio threshold in a numerical interval from the second ratio to the third ratio; and / or, the step of determining the difference threshold comprises: when the active noise reduction system is not unstable, obtaining a second acoustic feedback energy and a second total energy of a second sound signal collected by the reference microphone to calculate a second difference of the second acoustic feedback energy in the second total energy; wherein the second acoustic feedback energy is obtained according to a second control signal of the speaker and the acoustic feedback path; adjusting the gain of the acoustic feedback path to simulate the instability of the active noise reduction system, obtaining a third acoustic feedback energy and a third total energy of a third sound signal collected by the reference microphone to calculate a third difference of the third acoustic feedback energy in the third total energy; wherein the third acoustic feedback energy is obtained according to a third control signal of the speaker and the acoustic feedback path; selecting the difference threshold in a numerical interval from the second difference to the third difference.

2. The method of claim 1, wherein the instability is detected by determining a change in the at least one parameter. The adjustment of the gain of the acoustic feedback path to simulate the instability of the active noise reduction system comprises: decreasing the gain in a decreasing step by polling until the active noise reduction system is unstable.

3. The method of detecting destabilization according to claim 1 or 2, wherein in response to the first acoustic feedback energy and the first total energy meeting the instability condition, determining that the active noise reduction system is unstable, comprises: in response to the first acoustic feedback energy and the first total energy meeting the instability condition, determining that the active noise reduction system is unstable, comprises: in response to the first acoustic feedback energy and the first total energy meeting the instability condition, determining that the active noise reduction system is unstable, comprises:

4. A control method of an active noise reduction system, characterized by, The control method comprises: In the case where it is determined by the instability detection method according to any one of claims 1-3 that the active noise reduction system is unstable, restarting the active noise reduction system.

5. The control method according to claim 4, characterized by, The active noise reduction system further comprises a controller; the controller is used to convert a sound signal into a control signal; the restarting of the active noise reduction system comprises: Obtaining the number of consecutive instabilities of the active noise reduction system; In response to the number of consecutive instabilities being greater than or equal to a number threshold, shutting down the active noise reduction system and optimizing the controller; after restarting, the active noise reduction system performs active noise reduction based on the optimized controller.

6. A system for detecting instability, characterized by The instability detection system is used to implement the instability detection method according to any one of claims 1-3; the detection system comprises: An obtaining module, configured to obtain a first acoustic feedback energy and a first total energy of a first sound signal collected by the reference microphone; wherein the first acoustic feedback energy is obtained according to a first control signal of the loudspeaker and an acoustic feedback path; A response module, configured to determine that the active noise reduction system is unstable in response to the first acoustic feedback energy and the first total energy meeting an instability condition; wherein the instability condition comprises at least one of the following: a first ratio of the first acoustic feedback energy to the first total energy being greater than or equal to a ratio threshold, a first difference of the first total energy to the first acoustic feedback energy being less than or equal to a difference threshold, the first ratio being less than the ratio threshold and gradually increasing, and the first difference being less than the difference threshold and gradually increasing; The response module comprises: A first calculation unit, configured to, when the active noise reduction system is not unstable, obtain a second acoustic feedback energy and a second total energy of a second sound signal collected by the reference microphone, to calculate a second ratio of the second acoustic feedback energy to the second total energy; wherein the second acoustic feedback energy is obtained according to a second control signal of the loudspeaker and the acoustic feedback path; A second calculation unit, configured to, after adjusting the gain of the acoustic feedback path to simulate the active noise reduction system being unstable, obtain a third acoustic feedback energy and a third total energy of a third sound signal collected by the reference microphone, to calculate a third ratio of the third acoustic feedback energy to the third total energy; wherein the third acoustic feedback energy is obtained according to a third control signal of the loudspeaker and the acoustic feedback path; A first selection unit, configured to select the ratio threshold in a numerical interval of the second ratio to the third ratio; And / or; The response module comprises: A third calculation unit, configured to, when the active noise reduction system is not unstable, obtain a second acoustic feedback energy and a second total energy of a second sound signal collected by the reference microphone, to calculate a second difference of the second acoustic feedback energy in the second total energy; wherein the second acoustic feedback energy is obtained according to a second control signal of the loudspeaker and the acoustic feedback path; A fourth computing unit is configured to adjust the gain of the acoustic feedback path to simulate the instability of the active noise reduction system, obtain a third acoustic feedback energy and a third total energy of a third sound signal collected by the reference microphone, and calculate a third difference value of the third acoustic feedback energy in the third total energy; wherein the third acoustic feedback energy is obtained according to a third control signal of the loudspeaker and the acoustic feedback path; A second selecting unit is configured to select the difference value threshold in a numerical interval of the second difference value to the third difference value.

7. An active noise reduction system characterized by, The control method for implementing the active noise reduction system of claim 4 or 5; the active noise reduction system comprises: A detection module is configured to call a restart module when it is determined that the active noise reduction system is unstable according to the instability detection method of any one of claims 1-3; A restart module is configured to restart the active noise reduction system.

8. An appliance comprising a memory, a processor, and a computer program stored on the memory for running on the processor, characterized in that, The processor executes the computer program to implement the instability detection method of any one of claims 1-3 or the control method of the active noise reduction system of claim 4 or 5.

9. A computer readable storage medium having stored thereon a computer program, characterized in that, The computer program is executed by the processor to implement the instability detection method of any one of claims 1-3 or the control method of the active noise reduction system of claim 4 or 5.

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