KR101459317B1 - Method and apparatus for calibrating the sound source signal acquired through the microphone array - Google Patents

Abstract

The present invention relates to a method and an apparatus for correcting a sound source signal obtained through a microphone array, and a method for correcting a sound source signal according to the present invention is a method for correcting a sound source signal obtained through a microphone array, A microphone array is constructed in a digital device capable of acquiring a sound source by calculating probability distributions expressing numbers as probabilities and calculating reference probability distributions representing the calculated probability distributions and correcting the sound source signals according to the calculated reference probability distributions The problem that the sound source signal is distorted due to the characteristic mismatch between the individual microphones is solved.

Microphone array, calibration, probability distribution, histogram, nonlinear transformation

Description

[0001] The present invention relates to a method and apparatus for calibrating a sound source signal acquired through a microphone array,

The present invention relates to a method and an apparatus for correcting a sound source signal acquired through a microphone array, and relates to a portable sound acquiring device such as a mobile phone equipped with a microphone array, an ultra mobile personal computer (UMPC) And a method and apparatus for correcting a difference in characteristics of a sound source signal obtained in acquiring sound such as voice call, recording, and voice recognition in a digital information device such as a remote video conference system.

The time has come to become commonplace to make a phone call using a mobile phone or to acquire sound through a digital camcorder and a sound recorder. In a variety of digital devices, such as consumer electronics (CE) devices and mobile phones, a microphone is used as a means of acquiring sound, which is a stereo sound utilizing two or more channels rather than a single channel mono sound A microphone array including a plurality of microphones is generally used.

The microphone array can combine multiple microphones to obtain additional properties relating to the directivity as well as the sound itself as well as the direction or position of the sound to be acquired. The directivity means that the sensitivity of a sound source signal emitted from a sound source located in a specific direction is increased by using a time difference in which the sound source signal reaches each of a plurality of microphones constituting the array. Therefore, by acquiring sound source signals using such a microphone array, it is possible to emphasize or suppress the sound source signals inputted from a specific direction.

Adjusting the microphone array means adjusting the directivity adjustment parameters such as the delay value of each of the plurality of microphones constituting the microphone array or the interval between the microphones. Also, in order to control the microphone array as intended by the user, a basic precondition must be established that the microphone array must operate according to the physical characteristics of the individual microphones (meaning signal size, phase and frequency response).

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is an object of the present invention to provide a sound source signal correction method and a sound source signal correction method for solving the problem that a sound source signal inputted through a microphone array in a digital device capable of acquiring a sound source is distorted due to a characteristic mismatch between individual microphones constituting a microphone array Method and apparatus.

According to another aspect of the present invention, there is provided a method for correcting a sound source signal, the method comprising the steps of: calculating probability distributions representing the number of sound source signals present in each interval as a probability, according to magnitude intervals of sound source signals acquired through a microphone array; Calculating a reference probability distribution representing the calculated probability distributions; And correcting the sound source signals according to the calculated reference probability distribution.

According to another aspect of the present invention, there is provided a computer-readable recording medium having recorded thereon a program for causing a computer to execute the sound source signal correction method described above.

According to an aspect of the present invention, there is provided an apparatus for correcting a sound source signal, the apparatus comprising: a probability distribution calculating unit operable to calculate probability distributions representing the number of sound source signals existing in each interval, part; A reference probability distribution calculating unit for calculating a reference probability distribution representing the calculated probability distributions; And a signal correction unit for correcting the sound source signals according to the calculated reference probability distribution.

Hereinafter, various embodiments of the present invention will be described in detail with reference to the drawings. In describing the embodiments, a sound source will be used as a term meaning a source from which sound is emitted. In addition, the sound pressure is the expression of the force of the acoustic energy using the physical quantity of the pressure, and the sound pressure field is a conceptual representation of the area of the sound pressure around the sound source.

FIG. 1 is a block diagram illustrating a schematic idea of correcting a sound source signal in a problem situation to be solved by the present invention, and includes a microphone array 100, a sound source signal correcting section 110, and a signal processing section 120. Before describing each component, the problem situation to be solved by the present invention will be described first.

As described above, the microphone array is used to exploit the directional characteristics of the sound, such as directivity. In general, the microphone array improves the amplitude by giving a proper weight to each signal received by the microphone array to receive the target signal mixed with the background noise with a high sensitivity, thereby improving the noise when the desired target signal and the direction of the interference noise signal are different This kind of spatial filter is called a beamformer.

However, in order to process a sound source signal using such a beam shaper, the physical characteristics of each of the individual microphones constituting the microphone array must match those known to the user. In other words, the size, the phase, and the frequency response of the signals acquired through the individual microphones must match. This is because the factors for adjusting the microphone array are based on the physical characteristics of these individual microphones.

If the microphone source is delayed or the size of the source signal is changed for a certain period of time in order to adjust the microphone array, if the individual microphones constituting the microphone array are not adjusted according to the user's intention, It will be impossible to obtain a distorted sound source signal. For example, when attempting to eliminate unnecessary side-lobe artifacts in a generalized side-lobe canceller (GSC), which is an exemplary adaptive beamformer algorithm, the individual microphones constituting the microphone array If there is a characteristic mismatch between these characteristics, this characteristic mismatch causes signal leakage, resulting in a distortion of the sound source signal.

The above-mentioned characteristic inconsistencies between the microphones are mainly caused by the following two reasons. First, there are cases where the error occurs in the manufacturing process of the microphone. Secondly, the physical characteristics of the microphone may be changed by aging with the lapse of time in the process of using the microphone. Both of these causes are caused by the manufacturing process or the use process of the actual product, and inevitably occur in many cases. Therefore, various embodiments of the present invention to be described below are intended to correct the sound source signal so that the sound acquisition device is insensitive to the characteristic mismatch between the microphones when such problems occur in the sound acquisition device having the microphone array. Under such a problem, the schematic configuration of FIG. 1 will be described as follows.

The microphone array 100 acquires a sound source signal from the outside. The method of adjusting the microphone array 100 such as the direction of a sound source or the size of a sound source signal may be variously designed according to the situation and purpose in which the embodiment of the present invention is implemented.

The sound source signal correcting unit 110 corrects characteristic discrepancies of the sound source signals acquired through the microphone array 100. The following two methods are available as a method for solving the distortion problem of the sound source signal caused by the characteristic mismatch between the individual microphones. First, there may be a method of correcting each input sound source signal immediately when a sound source signal is input through the microphone array. Second, in a process of processing a sound source signal input through the microphone array according to a specific purpose, There may be a way to calibrate. The various embodiments of the present invention follow a method of directly correcting the electrons, i.e., the input signals themselves, of the above two solutions. This will be described in detail later with reference to FIG.

The signal processing unit 120 processes the corrected sound source signals through the sound source signal correcting unit 110 according to the purpose of the user. This may be freely designed according to various embodiments and environments in which the present invention is to be implemented, such as conventional sound source signal processing, beamformer, and sound source location tracker.

2 is a block diagram illustrating an apparatus for correcting a sound source signal according to an embodiment of the present invention. The microphone array 200, the reference probability distribution calculating unit 211, the signal correcting unit 212, and the signal processing unit 220 . The microphone array 200 and the signal processing unit 220 have the same configuration as the microphone array 100 and the signal processing unit 120 described in FIG. 1, and correspond to the configuration of a typical sound source signal processing apparatus. Therefore, in a more strict sense, the sound source signal correction apparatus according to the present embodiment includes a reference probability distribution calculating section 211 and a signal correction section 212 included in a region 210 indicated by a dotted line. Hereinafter, the sound source signal correction apparatus will be described in detail with reference to these two components.

The reference probability distribution calculating unit 211 calculates probability distributions representing the number of sound source signals present in each interval as probabilities for each magnitude interval of the sound source signals acquired through the microphone array 200. Generally, the probability distribution means the distribution of the probability variable, which corresponds to the probability value for each event that can occur in an attempt. In this case, the distribution state of the random variable can be calculated by counting the number of variables included in the interval obtained by dividing the variable by a predetermined width.

In the embodiments of the present invention, the probability distribution function (PDF) means that the size of the sound source signals is divided into a predetermined section and the number of corresponding sound source signals is counted for each section to express the probability. In general, a graph dividing a variable into arbitrary intervals and displaying the number of values included in each interval (also referred to as a frequency) is referred to as a histogram. Hereinafter, a graph indicating a graphical representation of a probability distribution will be.

The magnitude of the sound source signals from which the probability distribution is calculated can be expressed in various ways. Typically, the size of the signal in the time domain or the size of the signal in the frequency domain It will be possible.

The magnitude of the input signals in the time domain will be the amplitudes of the signals themselves. Therefore, the probability distribution can be calculated by dividing the amplitude of the input signals by a constant magnitude interval and counting the number of signals included in each interval. In order to obtain the magnitudes of the input signals in the frequency domain, the following procedure is followed.

First, for the digital signal processing of the excitation signals inputted through the microphone array 200, the frequency domain is transformed through a fast Fourier transform for convenience of operation. Generally, in digital signal processing, a convolution is used to input a signal to a corresponding system and express a resulting output signal, which is divided into frames in order to limit a given object signal finitely . A frame is a unit in which a sound source signal is separated into a predetermined section according to a change in time. Once the sound source signals are transformed into the frequency domain on a frame-by-frame basis, the process of calculating the probability distribution is similar to that in the time domain. That is, the probability distribution can be calculated by dividing the signal size of the main pseudo range by a constant magnitude interval and counting the number of signals included in each interval.

The reference probability distribution calculating unit 211 first calculates the degree of distribution of the sound source signals for each of the above intervals as a probability, and calculates a reference value representative of the respective sound source signals from the calculated results. This reference value is a reference probability distribution, and it is a measure for correcting the respective sound source signals in a subsequent step.

Hereinafter, the process of calculating the reference probability distribution from the sound source signals input by the reference probability distribution calculating unit 211 will be described in more detail with reference to FIGS. 4, 5A and 5B. In the following embodiments, the probability distributions as the mood probability distributions will use cumulative probability distributions in which the signal magnitudes are smaller to the larger ones, and the normal cumulative probability distributions obtained by normalizing the cumulative probability distributions to specific values will be used. As a matter of course, it is possible to use means for representing various probability distributions in addition to the cumulative probability distribution and the normal cumulative probability distribution. Hereinafter, specific meanings and configurations will be described.

FIG. 4 is a diagram illustrating a method of calculating a cumulative probability distribution in a sound source signal correction apparatus according to an embodiment of the present invention. The first graph illustrates a histogram of a probability distribution of sound source signals input through a microphone array And the second graph is an example of a histogram that accumulates and normalizes the probability distribution of the sound source signals. The horizontal axis of the graph represents a magnitude interval of the sound source signal and the vertical axis represents the number of sound source signals corresponding to each interval as a probability distribution. In FIG. 4, it is assumed that the microphone array is composed of four microphones, and the sound source signals inputted through the respective microphones are represented by four channels.

In the left graph of FIG. 4, although the input sound source signals are the same, a difference between probability distributions appears for each channel. That is, we can see that there is a characteristic mismatch between the microphones. If these probability distributions are accumulated in a larger scale from the smaller side to the larger side with respect to the horizontal axis and a histogram is shown, a graph in which the signal size increases as shown in FIG. 4 will be drawn. However, the accumulated cumulative probability distributions do not match the accumulated maximum values due to the characteristic mismatch between the microphones described above. That is, the cumulative results of the probability distributions are different from each other. Therefore, a normalization process for matching the cumulative results is performed. Here, the normalization means that the maximum value is matched with a specific value as a reference for easy calculation. In this embodiment, the maximum value of the accumulated probability distribution is set to 1 and the minimum value is set to 0. The histogram generated through the above process is shown in the second graph of FIG. The second graph in FIG. 4 is a histogram showing a normalized cumulative probability distribution function. The vertical axis is normalized to 1, and the probability distributions of the four channels gradually increase as they progress to the right As shown in FIG.

5A and 5B are block diagrams illustrating a detailed configuration of calculating a reference cumulative probability distribution in a sound source signal correction apparatus according to an embodiment of the present invention, and show a specific configuration for generating the histogram of FIG. 4 .

5A, the reference cumulative probability distribution calculating unit includes a normal cumulative probability distribution calculating unit 510 and a representative value calculating unit 520. [

As described above, the normal cumulative probability distribution calculating unit 510 calculates the normal cumulative probability distributions corresponding to the sound source signals from the signal distributions of the magnitude intervals of the sound source signals received through the microphone array. Referring to FIG. 5B, the normal cumulative probability distribution calculating unit 510 includes an accumulating unit 511 and a normalizing unit 512. The accumulation unit 511 calculates and accumulates probability distributions of the magnitudes of the signals according to magnitude intervals of the excitation signals. The normalization unit 512 normalizes the accumulated maximum values for the probability distributions accumulated through the accumulation unit 511 to coincide with each other.

The representative value calculating unit 520 calculates a representative value from the normal cumulative probability distributions calculated through the normal cumulative probability distribution calculating unit 510 and sets the representative cumulative probability distribution. When a sound source signal is generated by the number of individual microphones constituting the microphone array, and a normal cumulative probability distribution corresponding to the generated sound source signal is calculated, a representative value representative of the representative cumulative probability distribution is calculated and set as a criterion for subsequent sound source signal correction . For example, assuming that there are four individual microphones, four regular cumulative probability distributions will be calculated, and one standard cumulative probability distribution is calculated from these four regular cumulative probability distributions according to a specific rule. Here, the specific rule may be implemented in the form of an arbitrary function that calculates a representative value.

As a method for calculating the representative value, various methods can be used, which typically select values that can represent arbitrary values, and these methods can be easily obtained by those having ordinary skill in the art to which the present invention belongs. It is. Representative methods of calculating representative values will be briefly described as follows.

First, it can be set to the representative value by using the average value (average). That is, an average value of signal magnitudes of a plurality of normal cumulative probability distributions is obtained and set as a reference cumulative probability distribution. Second, it can be set as a representative value using the median. This method is a method of setting the normal cumulative probability distribution corresponding to the median value of the signal size to the reference cumulative probability distribution considering the degree of distribution of the sound signals. In addition to the above methods, a method may be used in which one or more sound source signals among a plurality of sound source signals are selected, more weight is given to the selected sound source signals, and a representative value is calculated.

The process of calculating the reference cumulative probability distribution in the reference probability distribution calculating unit 211 of FIG. 2 has been described. Through this process, when there is a difference between the input sound signals due to the characteristic mismatch between the plurality of microphones, a reference cumulative probability distribution serving as a reference for correcting the sound source signals can be obtained.

Next, the signal correcting unit 212 corrects the sound source signals according to the reference cumulative probability distribution calculated through the reference probability distribution calculating unit 211. [ Accordingly, the signal corrector 212 may exist as many as the number of individual microphones constituting the microphone array, and corrects the respective sound source signals (meaning channels) by referring to the reference cumulative probability distribution. Hereinafter, a method of correcting the excitation signals in the signal corrector 212 will be described in more detail with reference to FIGS. 6 and 7. FIG.

6 is a detailed block diagram illustrating a configuration of a sound source signal correction apparatus according to an exemplary embodiment of the present invention that corrects a sound source signal using a conversion function. The signal correction unit 620 further includes a probability distribution conversion unit 621 ).

First, the normal cumulative probability distribution is calculated from the sound source signals through the normal cumulative probability distribution calculating unit 610. This process is as described in FIG. 2 above. Next, the probability distribution transforming unit 621 transforms the corrected sound source signals from the normal cumulative probability distributions calculated through the normal cumulative probability distribution calculating unit 610 using a function of converting the sound source signals into the reference cumulative probability distribution . That is, the normal cumulative probability distribution is corrected according to the reference value. This correction process is performed through a sample-by-sample comparison process according to the reference cumulative probability distribution. The sample-to-sample comparison refers to a comparison of a specific sample of a sound source signal before correction with a corresponding reference sample (which means a value according to a reference cumulative probability distribution). To help understand the above conversion process, refer to FIG.

7 is a diagram illustrating a method of generating a corrected sound source signal in a probability distribution conversion unit of a sound source signal correction apparatus according to an embodiment of the present invention. The graph shown by the solid line in FIG. 7 is the histogram of the reference cumulative probability distribution, and the graph shown by the dotted line is the histogram of the normal cumulative probability distribution corresponding to the currently uncorrected sound source signal. It is assumed that the vertical axis of the graph is normalized to a value from 0 to 1. Correction of the sound source signal means that the normal cumulative probability distribution value for a specific sample is matched to the reference cumulative probability distribution value.

For example, when the A value on the horizontal axis of the graph shows a specific value (meaning a sample) of the sound source signal that is not corrected, the cumulative probability distribution corresponding to the A value will be the C value on the vertical axis. In this case, if the input value corresponding to this cumulative probability distribution is inversely estimated based on the C value, the corrected input signal will be the B value in the horizontal axis of the histogram of the reference cumulative probability distribution. That is, the B value is a signal obtained by correcting the uncorrected microphone input signal A value.

The process of correcting the tone signal by the signal corrector 212 of FIG. 2 has been described with reference to FIGS. 6 and 7. FIG. Hereinafter, a process of calculating the reference probability distribution in the sound source signal correction apparatus 210 of FIG. 2 and a process of correcting the sound source signal in accordance with the calculated reference probability distribution will be described below with reference to the mathematical expression.

이라고 하면, 이들 마이크로폰 입력 신호들에 대응하는 정규 누적 확률 분포들은

와 같이 표현할 수 있다. 이 때, 정규 누적 확률 분포들은

이라는 조건을 만족한다. 이어서, 마이크로폰 입력 신호 각각의 누적 확률 분포로부터 기준 누적 확률 분포를 산출하면 다음의 수학식 1과 같이 표현된다.First, assuming that the number of individual microphones constituting the microphone array is k, k microphone input signals

, Normal cumulative probability distributions corresponding to these microphone input signals < RTI ID = 0.0 >

Can be expressed as At this time, the normal cumulative probability distributions

Is satisfied. Next, the reference cumulative probability distribution is calculated from the cumulative probability distribution of each of the microphone input signals, as expressed by the following Equation (1).

은 기준 누적 확률 분포에 따른 함수이고, f(·)는 대표값을 산출하는 함수를 의미한다. 앞서 도 5a에서 설명한 바와 같이 f(·)는 평균값이나 중앙값을 구하는 함수가 될 수 있을 것이다.here,

Is a function according to the reference cumulative probability distribution, and f (·) is a function that calculates a representative value. As described above with reference to FIG. 5A, f (.) May be a function for obtaining an average value or a median value.

Next, the process of correcting the microphone input signal to follow the reference cumulative probability distribution is expressed as Equation 2 below.

는 보정되지 않은 마이크로폰 입력 신호이고,

는 보정된 마이크로폰 입력 신호를 의미한다. 또한,

는 정규 누적 확률 분포에 따른 함수이고,

은 기준 누적 확률 분포에 따른 함수를 의미한다. 즉, 수학식 2는 앞서 도 7을 통해 설명한 바와 같이, 특정 입력 신호에 대한 정규 누적 확률 분포 값을 기준 누적 확률 분포 값에 일치시키는 입력 신호 보정 과정을 나타낸다.here,

Is an uncorrected microphone input signal,

Means a corrected microphone input signal. Also,

Is a function according to the normal cumulative probability distribution,

Denotes a function according to the reference cumulative probability distribution. Equation (2) represents an input signal correction process for matching the normal cumulative probability distribution value of a specific input signal with a reference cumulative probability distribution value, as described above with reference to FIG.

Equation (2) can be summarized with the corrected microphone input signal as a center.

및

과 같은 확률 분포에 따른 함수들은 일종의 비선형 변환 함수들로서, 수학식 3을 통해 도 2의 신호 보정부(212)는 최종적으로 보정된 음원 신호를 생성하여 신호 처리부(220)에 공급한다.ideal

And

The signal corrector 212 of FIG. 2 generates a final corrected sound source signal and supplies the corrected sound source signal to the signal processing unit 220 through Equation (3).

The signal processing unit 220 is typically provided in a digital signal processing apparatus having a microphone array. Since the signal processing unit 220 can be freely designed according to the environment in which the embodiments of the present invention are implemented, detailed description is omitted here.

The configuration and the role of the sound source signal correction apparatus have been described in detail with reference to the various embodiments of the present invention. According to the present embodiments, the reference probability distribution is calculated based on the probability distributions of the sound source signals input through the microphone array, and the sound source signals are corrected accordingly, whereby the individual microphones The problem that the sound source signal is distorted due to the characteristic mismatch between the signals is eliminated. In addition, once the reference probability distribution is calculated, input sound source signals can be corrected in real time, so that quick error compensation becomes possible.

FIG. 3 is a block diagram illustrating a sound source signal correction apparatus to which a storage unit according to another embodiment of the present invention is added, in which a storage unit 315 is added to the sound source signal correction apparatus 210 of FIG.

3 includes a reference probability distribution calculating unit 311 and a signal correcting unit 312 as in FIG. 2, and therefore features of the configuration will be described with the storage unit 315 as a center.

The storage unit 315 stores the reference probability distribution calculated through the reference probability distribution calculating unit 311. [ As described above, the property mismatch between microphones is caused by errors in the manufacturing process of the microphones and aging due to use of the microphones. Therefore, once a characteristic mismatch occurs, there is a high possibility that such a problem will not change greatly within a short time. That is, the property mismatch itself slowly changes with time. Therefore, once the baseline cumulative probability distribution is calculated, it is not necessary to calculate it several times in a short time. Rather, if the reference probability distribution is calculated each time the sound source signal is corrected, it will be a waste of system resources.

For this reason, the storage unit 315 stores the calculated reference probability distribution so that it does not have to be calculated again. The storage unit 315 may be a recording device capable of recording data or a specific storage device connected through a network. Then, the signal correction unit 312 reads the reference probability distribution stored in the storage unit 315, and corrects the sound source signals according to the read reference probability distribution. 3, if it is determined that the sound source signal correction apparatus 310 has performed a predetermined period of time or that the characteristics of the microphones have changed, the reference signal distribution unit 311 newly calculates the reference probability distribution again through the reference probability distribution calculating unit 311 And updating the newly calculated reference probability distribution to the storage unit 315, thereby solving the characteristic mismatch between the changed microphones.

In this embodiment, the reference probability distribution is not repeatedly calculated, and the reference probability distribution once calculated is stored. However, the unnecessary calculation is reduced by utilizing the reference probability distribution for correction of the sound source signal. Once the reference probability distribution is calculated, It is possible to omit it, and it is possible to correct the sound source signal quickly.

FIG. 8 is a flowchart illustrating a sound source signal correction method according to another embodiment of the present invention, which includes the following steps.

In step 810, probability distributions representing the number of sound source signals present in each interval as probability are calculated for each magnitude interval of the sound source signals acquired through the microphone array. Probability distributions can be calculated through a normalization process of accumulating probability distributions of sound source signals and then matching the maximum values.

The reference probability distribution representing each of the probability distributions is calculated based on the probability distributions calculated in step 820 through step 810. [ The reference probability distribution can be obtained by calculating a representative value such as an average value or a median value from the calculated probability distributions and setting the reference probability distribution.

In step 830, the sound source signals acquired in step 810 are corrected according to the reference probability distribution calculated in step 820. [ The corrected sound source signals can be obtained from the sound source signals by inputting probability distributions using an inverse function of a function for converting to a reference probability distribution calculated in step 810. [

According to the present embodiment, the problem that the sound source signal is distorted due to the characteristic mismatch between the individual microphones constituting the microphone array is solved, and the correction of the sound source signal is performed in real time according to the calculated reference cumulative probability distribution. Do.

Meanwhile, the present invention can be embodied in computer readable code on a computer readable recording medium. A computer-readable recording medium includes all kinds of recording apparatuses in which data that can be read by a computer system is stored.

Examples of the computer-readable recording medium include a ROM, a RAM, a CD-ROM, a magnetic tape, a floppy disk, an optical data storage device, and the like in the form of a carrier wave (for example, transmission via the Internet) . In addition, the computer-readable recording medium may be distributed over network-connected computer systems so that computer readable codes can be stored and executed in a distributed manner. In addition, functional programs, codes, and code segments for implementing the present invention can be easily deduced by programmers skilled in the art to which the present invention belongs.

Various embodiments of the present invention have been described above. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. Therefore, the disclosed embodiments should be considered in an illustrative rather than a restrictive sense. The scope of the present invention is defined by the appended claims rather than by the foregoing description, and all differences within the scope of equivalents thereof should be construed as being included in the present invention.

1 is a block diagram illustrating a schematic idea of correcting a sound source signal in a problem situation to be solved by the present invention.

2 is a block diagram illustrating a sound source signal correction apparatus according to an embodiment of the present invention.

3 is a block diagram illustrating a sound source signal correction apparatus to which a storage unit according to another embodiment of the present invention is added.

4 is a diagram illustrating a method of calculating a cumulative probability distribution in a sound source signal correction apparatus according to an embodiment of the present invention.

5A and 5B are block diagrams illustrating a detailed configuration of calculating a reference cumulative probability distribution in a sound source signal correction apparatus according to an embodiment of the present invention.

6 is a block diagram illustrating in detail a configuration for correcting a sound source signal using a conversion function in a sound source signal correction apparatus according to an embodiment of the present invention.

7 is a diagram illustrating a method of generating a corrected sound source signal in a probability distribution conversion unit of a sound source signal correction apparatus according to an embodiment of the present invention.

8 is a flowchart illustrating a sound source signal correction method according to another embodiment of the present invention.

Claims (13)

Calculating probability distributions representing the number of sound source signals present in each interval as probabilities for each magnitude interval of the same sound source signals acquired through a microphone array; Calculating a reference probability distribution representing the probability distributions based on the calculated probability distributions; And And correcting the sound source signals according to the calculated reference probability distribution. The method according to claim 1, Wherein the calculating of the probability distributions comprises calculating and accumulating probability distributions of the magnitudes of the sound source signals for each of the intervals, Wherein the step of calculating the reference probability distribution calculates the reference probability distribution based on the accumulated probability distributions. 3. The method of claim 2, Wherein the step of calculating the probability distributions further comprises the step of normalizing the cumulative probability distributions such that the maximum values of the cumulative probability distributions coincide with a predetermined value, Wherein the step of calculating the reference probability distribution calculates the reference probability distribution based on the normalized cumulative probability distributions. The method according to claim 1, Wherein the step of calculating the reference probability distribution calculates an average value or a median value from the calculated probability distributions and sets the reference probability distribution as the reference probability distribution. The method according to claim 1, Wherein the step of correcting the sound source signals comprises generating the corrected sound source signals by inputting the probability distributions into an inverse function of a function of converting the sound source signals into the reference probability distribution. The method according to claim 1, Further comprising the step of previously storing the calculated reference probability distribution, Wherein the step of correcting the sound source signals comprises reading the pre-stored reference probability distribution and correcting the sound source signals according to the read reference probability distribution. A computer-readable recording medium storing a program for causing a computer to execute the method according to any one of claims 1 to 6. A probability distribution calculating unit for calculating probability distributions representing the number of the sound source signals present in each interval as probabilities according to magnitude intervals of the same sound source signals acquired through the microphone array; A reference probability distribution calculating unit for calculating a reference probability distribution representing the probability distributions based on the calculated probability distributions; And And a signal correction unit for correcting the sound source signals according to the calculated reference probability distribution. 9. The method of claim 8, Wherein the probability distribution calculating unit includes an accumulating unit for calculating and accumulating probability distributions of magnitudes of the sound source signals for each of the intervals, Wherein the reference probability distribution calculating unit calculates the reference probability distribution based on the accumulated probability distributions. 10. The method of claim 9, Wherein the probability distribution calculating unit further includes a normalizing unit for normalizing the accumulated probability distributions such that maximum values of the accumulated probability distributions are equal to a predetermined value, Wherein the reference probability distribution calculating unit calculates the reference probability distribution based on the normalized cumulative probability distributions. 9. The method of claim 8, Wherein the reference probability distribution calculating unit calculates an average value or a median value from the calculated probability distributions and sets the reference probability distribution as the reference probability distribution. 9. The method of claim 8, Wherein the signal corrector comprises a probability distribution transformer for generating corrected sound source signals by inputting the probability distributions into an inverse function of a function for converting from the sound source signals to the reference probability distribution. 9. The method of claim 8, And a storage unit for storing the calculated reference probability distribution in advance, Wherein the signal correction unit reads the pre-stored reference probability distribution and corrects the sound source signals according to the read reference probability distribution.

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