Sound source estimation method

Abstract

To increase estimation accuracy of a source of sound.SOLUTION: A sound source estimation method performs: first processing of acquiring a frequency of the largest sound at each time as first sound information from sound data during a predetermined period to estimate a source of the sound on the basis of the first sound information (S13); second processing of generating processed sound data from the sound data and acquiring a frequency of the largest sound at each time as second sound information from the processed sound data to estimate the source of the sound on the basis of the second sound information (S15); and third processing of estimating the source of the sound on the basis of an estimation result in the first processing and an estimation result in the second processing (S17).SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a sound source estimation method.

Background Art

[0002] Patent Document 1 discloses a sound source estimation system for estimating candidates for the sound source of abnormal noise. In this system, in frequency sound data representing changes in the frequency spectrum during a predetermined period, the maximum sound frequency, which is the frequency indicating the loudest sound, is extracted. Based on the maximum sound frequency and the rotational speed of the component, the order is calculated. Then, the component having the order closest to the calculated order is estimated as the sound source of the abnormal noise.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above system for estimating the sound source of abnormal noise using the maximum sound frequency, when the noise other than the abnormal noise is large, it becomes difficult to estimate the sound source of the abnormal noise.

Means for Solving the Problems

[0005] A sound source estimation method to solve the above problem involves causing a control device to execute the following: a first process which involves obtaining the frequency of the loudest sound at each time from sound data over a predetermined period as first sound information and estimating the sound source based on the first sound information; a second process which involves generating processed sound data from the sound data, excluding sound data in the frequency range of the sound emitted from the sound source estimated in the first process, obtaining the frequency of the loudest sound at each time from the processed sound data as second sound information and estimating the sound source based on the second sound information; and a third process which involves estimating the sound source based on the estimation results from the first process and the estimation results from the second process. [Effects of the Invention]

[0006] The above sound source estimation method can improve the accuracy of estimating the source of sound. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 is a flowchart showing one embodiment of the sound source estimation method. [Figure 2] In Figure 2, (A) is a diagram showing an example of first sound information, (B) is a diagram showing the frequency progression of the noise, and (C) is a diagram showing the estimation result of the source of the abnormal sound in the first processing. [Figure 3] In Figure 3, (A) is a diagram showing an example of second-order sound information, and (B) is a diagram showing the estimation result of the source of the abnormal sound in the second processing. [Figure 4] Figure 4 shows the estimated source of the abnormal noise in the third processing step. [Modes for carrying out the invention]

[0008] An embodiment of the sound source estimation method will be described below with reference to Figures 1 to 4. <Configuration of the sound source estimation method> One example of a sound source estimation method is a method for estimating the source of an unusual noise occurring in a vehicle. When a vehicle occupant notices an unusual noise, they operate a button provided in the vehicle, for example. This button is an operation unit that initiates a series of processes to identify the source of the unusual noise.

[0009] Figure 1 illustrates a series of processes for identifying the source of an abnormal noise. These processes are performed by a control device. In step S11, the control device acquires sound data for a predetermined period by having a sound collection device such as a microphone collect sound. The sound data for the predetermined period is time-series data including the loudness and frequency of the collected sound.

[0010] In step S13, the control device performs a first process to estimate the source of the abnormal noise by analyzing sound data over a predetermined period. Specifically, the control device acquires the maximum sound frequency at each time point as the first sound information from the sound data during a predetermined period (S131). The maximum sound frequency is the frequency of the loudest sound. Figure 2(A) shows an example of the first sound information.

[0011] Next, the control device estimates the source of the abnormal noise based on the first information (S133). Figure 2(B) shows the frequency progression of switching noise, which is noise generated when an in-vehicle switch is activated, as shown by line 1, L1. As lines showing the frequency progression of noise when the motor is driven, line 2, L2, shows the frequency progression of 48th-order noise, and line 3, L3, shows the frequency progression of 24th-order noise.

[0012] The control device obtains the number of plots included in a predetermined frequency region containing the first line L1, the number of plots included in a predetermined frequency region containing the second line L2, and the number of plots included in a predetermined frequency region containing the third line L3 from among the multiple plots shown in Figure 2. The control device then calculates the matching ratio of the switching noise, the matching ratio of the 48th order of motor noise, and the matching ratio of the 24th order of motor noise. For example, the control device can calculate the matching ratio of the switching noise by dividing the number of plots included in the predetermined frequency region containing the first line L1 by the total number of plots in Figure 2.

[0013] Figure 2(C) illustrates an example of the estimated source of the abnormal noise based on the first sound information. In this case, the control device indicates that the switch is the most likely source of the abnormal noise.

[0014] Then, once the control device has finished the first process, it moves the process to the next step S15. In step S15, the control device performs a second process to estimate the source of the abnormal noise by analyzing the processed sound data, which will be described later.

[0015] Specifically, the control device generates processed sound data (S151) based on the sound data acquired in step S11 and the first sound information. Specifically, the control device generates processed sound data by excluding sound data in the frequency range of the sound emitted from the source of the abnormal sound estimated in the first processing from the sound data.

[0016] Next, the control device acquires the maximum sound frequency at each time point from the processed sound data as second sound information (S153). An example of second sound information is shown in Figure 3(A). The control device then estimates the source of the abnormal noise based on the second information (S155). The method for estimating the source here is the same as the estimation method in step S133. Figure 3(B) shows an example of the result of estimating the source of the abnormal noise based on the second information.

[0017] When the control device finishes the second process, it proceeds to the next step S17. In step S17, the control device executes a summation process. The summation process corresponds to a "third process" of estimating the sound source based on the estimation results in the first process and the estimation results in the second process.

[0018] Figure 4 shows the result of the summation process. Specifically, the control device multiplies both the first matching rate, which is the matching rate in the first process, and the second matching rate, which is the matching rate in the second process, by a weighting coefficient. Then, the control device calculates the sum of the first matching rate and the second matching rate after correction by the weighting coefficient as the matching rate. In Figure 4, the weighting coefficient for the first matching rate is 1, and the weighting coefficient for the second matching rate is 0.8. However, these are just examples, and different values may be set as the weighting coefficients.

[0019] When the control device finishes the summation process, it proceeds to step S19. In step S19, the control device notifies the occupant of the result of the summation process. For example, the control device may display the result on an in-vehicle display.

[0020] <Advantages of this Embodiment> In this embodiment, the source of the abnormal sound is estimated by considering sounds other than the loudest sound. This makes it possible to identify multiple sources when there are multiple sources of abnormal sound.

Explanation of Reference Numerals

[0021] S13... First process, S15... Second process, S17... Summation process.

Claims

[Claim 1] A first process involves obtaining the frequency of the loudest sound at each time point from sound data over a predetermined period as first sound information, and estimating the sound source based on this first sound information. A second process is performed to generate processed sound data from the aforementioned sound data, excluding sound data in the frequency range of the sound emitted from the sound source estimated in the first process; to obtain the frequency of the loudest sound at each time point from the processed sound data as second sound information; and to estimate the sound source based on the second sound information. The control device is instructed to perform a third process, which estimates the sound source based on the estimation results from the first process and the estimation results from the second process. Sound source estimation method.

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