Determination Device, Determination Method, Computer Program, and Recording Medium

Abstract

To determine whether a living body sound is detected correctly, while keeping cost down.SOLUTION: A determination device (20) determines whether a living body sound is detected correctly by a living body sound detection device (10), having a first sensor (11) for acquiring first sound information containing the living body sound when detecting the living body sound of an object (1), and a second sensor (12) arranged in a position separated from the object more than the first sensor and acquiring second sound information containing the sound around the object. The determination device includes: acquisition means (21a, 21b) for acquiring the first sound information and the second sound information; extraction means (24a, 24b) for extracting a first low frequency component being the low frequency component contained in the first sound information, and a second low frequency component being the low frequency component contained in the second sound information; and determination means (27) for determining whether the living body sound detection device detects the living body sound correctly, on the basis of results of comparison between the first low frequency component and the second low frequency component.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to the technical fields of a determination device, a determination method, a computer program, and a recording medium for determining whether a biological sound detection device correctly detects a target biological sound.

Background Art

[0002] As this type of device, for example, one or a plurality of contact detection sensor pairs are arranged around a auscultatory sound sensor in a chest piece, and based on the contact detection results of the paired contact detection sensors, it is determined whether the contact state is appropriate for acquiring auscultatory sounds correctly. A device has been proposed (see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the technique described in Patent Document 1, it is necessary to prepare at least one contact detection sensor pair (that is, two contact detection sensors) separately from the auscultatory sound sensor, and there are technical problems such as relatively high product costs, for example.

[0005] The present invention has been made in view of the above problems, and an object thereof is to provide a determination device, a determination method, a computer program, and a recording medium that can determine whether a biological sound detection device correctly detects a target biological sound while suppressing costs.

Means for Solving the Problems

[0006] In order to solve the above problems, the determination device of the present invention is a determination device that determines whether a biological sound detection device having a first sensor that acquires first sound information including the biological sound and a second sensor that is disposed at a position farther from the target than the first sensor and acquires second sound information including the sound around the target correctly detects the biological sound. The determination device includes an acquisition unit that acquires the first sound information and the second sound information, an extraction unit that extracts a first low-frequency component that is a low-frequency component included in the first sound information and a second low-frequency component that is a low-frequency component included in the second sound information, and a determination unit that determines whether the biological sound detection device correctly detects the biological sound based on a comparison result between the first low-frequency component and the second low-frequency component. The determination means calculates a correlation coefficient between the first low-frequency component and the second low-frequency component, and determines that the biological sound detection device is not correctly detecting the biological sound when the correlation coefficient is smaller than a predetermined threshold value, and determines that the biological sound detection device is correctly detecting the biological sound when the correlation coefficient is larger than the predetermined threshold value 。

[0007] In order to solve the above problems, the determination method of the present invention is a determination method that determines whether a biological sound detection device having a first sensor that acquires first sound information including the biological sound and a second sensor that is disposed at a position farther from the target than the first sensor and acquires second sound information including the sound around the target correctly detects the biological sound. The determination method includes an acquisition step of acquiring the first sound information and the second sound information, an extraction step of extracting a first low-frequency component that is a low-frequency component included in the first sound information and a second low-frequency component that is a low-frequency component included in the second sound information, and a determination step of determining whether the biological sound detection device correctly detects the biological sound based on a comparison result between the first low-frequency component and the second low-frequency component. As described above, the determination step includes a calculation step of calculating a correlation coefficient between the first low-frequency component and the second low-frequency component, and it is determined that the biological sound detection device is not correctly detecting the biological sound when the correlation coefficient is smaller than a predetermined threshold value, and it is determined that the biological sound detection device is correctly detecting the biological sound when the correlation coefficient is larger than the predetermined threshold value 。

[0008] In order to solve the above problems, the computer program of the present invention causes a computer of a determination device that determines whether a biometric sound detection device having a first sensor that acquires first sound information including the biometric sound when detecting the biometric sound of an object and a second sensor that is disposed at a position farther from the object than the first sensor and acquires second sound information including the sound around the object correctly detects the biometric sound, to function as acquisition means for acquiring the first sound information and the second sound information, and extraction means for extracting a first low-frequency component that is a low-frequency component included in the first sound information and a second low-frequency component that is a low-frequency component included in the second sound information. Determination means including calculation means for calculating a correlation coefficient between the first low-frequency component and the second low-frequency component, determining that the biological sound detection device is not correctly detecting the biological sound when the correlation coefficient is smaller than a predetermined threshold value, and determining that the biological sound detection device is correctly detecting the biological sound when the correlation coefficient is larger than the predetermined threshold value Function as.

[0009] In order to solve the above problems, the recording medium of the present invention stores the computer program of the present invention described above.

[0010] The operations and other advantages of the present invention will become apparent from the following embodiments for carrying out the invention.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Embodiments for Carrying Out the Invention

[0012] (Determination device) An embodiment of a determination device will be described. The determination device according to the embodiment determines whether a biometric sound detection device correctly detects a biometric sound of an object. The biometric sound detection device has a first sensor and a second sensor. The first sensor acquires first sound information including the biometric sound when detecting the biometric sound of the object. The second sensor is disposed at a position farther from the object than the first sensor when detecting the biometric sound of the object. The second sensor acquires second sound information including the sound around the object.

[0013] Here, the first sound information mainly includes sound information related to the biological sound, but may also include sound information related to the sound around the target. The second sound information mainly includes sound information related to the sound around the target, but may also include sound information related to the biological sound. By the way, the sound information related to the sound around the target that may be included in the first sound information becomes noise for the sound information related to the biological sound. By referring to the second sound information mainly including the sound information related to the sound around the target, the noise included in the first sound information can be removed or reduced. Note that since the method of removing or reducing noise is not an essential feature of the determination device, its description is omitted.

[0014] The determination device is configured to include an acquisition means, an extraction means, and a determination means. The acquisition means acquires the first sound information and the second sound information from the biological sound detection device. The extraction means extracts a first low-frequency component that is a low-frequency component included in the first sound information. The extraction means also extracts a second low-frequency component that is a low-frequency component included in the second sound information. Note that since existing technologies can be applied to the method of extracting the low-frequency component from the sound information, the detailed description thereof is omitted. The determination means determines whether the biological sound detection device correctly detects the biological sound of the target based on the comparison result between the first low-frequency component and the second low-frequency component.

[0015] As described above, the second sound information acquired by the second sensor may also include information related to the biological sound. This is because when the biological sound detection device is appropriately in contact with the target, the vibration generated related to the biological sound propagates throughout the biological sound detection device, and the vibration is detected by the second sensor. Also, the frequency related to the biological sound is relatively low. When the biological sound detection device is appropriately in contact with the target, since the second sound information includes information related to the biological sound, the second low-frequency component is relatively similar to the first low-frequency component. On the other hand, when the biological sound detection device is not appropriately in contact with the target, the second low-frequency component is relatively deviated from the first low-frequency component. Therefore, by comparing the first low-frequency component and the second low-frequency component, it is possible to determine whether the biological sound detection device correctly detects the biological sound of the target.

[0016] As described above, the second sound information acquired by the second sensor can be used, for example, to remove or reduce noise included in the first sound information acquired by the first sensor. That is, in the determination device, for example, the second sound information used for noise removal or the like is also used to determine whether the biological sound detection device correctly detects the target biological sound. In other words, the determination device does not need to provide a dedicated member to the biological sound detection device in order to determine whether the biological sound detection device correctly detects the target biological sound. Therefore, according to the determination device, it is possible to determine whether the biological sound detection device correctly detects the target biological sound while suppressing costs.

[0017] (Determination method) An embodiment of the determination method will be described. The determination method according to the embodiment determines whether the biological sound detection device correctly detects the target biological sound. The configuration of the biological sound detection device is the same as that of the embodiment according to the determination device described above, and thus the description thereof is omitted.

[0018] The determination method includes an acquisition step, an extraction step, and a determination step. In the acquisition step, the first sound information and the second sound information are acquired. In the extraction step, a first low-frequency component, which is a low-frequency component included in the first sound information, is extracted. Also, in the extraction step, a second low-frequency component, which is a low-frequency component included in the second sound information, is extracted. In the determination step, based on the comparison result between the first low-frequency component and the second low-frequency component, it is determined whether the biological sound detection device correctly detects the biological sound.

[0019] According to the determination method, similarly to the determination device according to the above-described embodiment, it is possible to determine whether the biological sound detection device correctly detects the target biological sound while suppressing costs.

[0020] (Computer program) Embodiments related to a computer program will be described. The computer program according to the embodiments causes a computer of a determination device that determines whether a biological sound detection device correctly detects a biological sound when detecting the target biological sound to function as an acquisition unit that acquires first sound information and second sound information, an extraction unit that extracts a first low-frequency component that is a low-frequency component included in the first sound information and extracts a second low-frequency component that is a low-frequency component included in the second sound information, and a determination unit that determines whether the biological sound detection device correctly detects the biological sound based on a comparison result between the first low-frequency component and the second low-frequency component. Note that the configuration of the biological sound detection device is the same as that of the embodiments related to the determination device described above, and thus the description thereof is omitted.

[0021] According to the computer program, if the computer program is read from a recording medium such as a RAM (Random Access Memory), a CD-ROM (Compact Disc Read Only Memory), or a DVD-ROM (DVD Read Only Memory) that stores the computer program and executed by a computer that constitutes the determination device, or if the computer program is executed after being downloaded via a communication means, the determination device according to the above-described embodiments can be relatively easily realized. As a result, similar to the determination device according to the above-described embodiments, it is possible to determine whether the biological sound detection device correctly detects the target biological sound while suppressing costs.

[0022] Here, a recording medium such as a CD-ROM or a DVD-ROM on which the computer program is recorded corresponds to an example of an embodiment related to the recording medium.

Example

[0023] An example related to the determination device will be described with reference to FIGS. 1 and 2. In this example, in a system that continuously monitors the biological sound of Subject 1, a determination device 20 that determines whether a biological sound detection device 10 correctly detects the biological sound will be described.

[0024] The biological sound detection device 10 includes a first sensor 11 and a second sensor 12. The first sensor 11 and the second sensor 12 may be sensors capable of acquiring biological sounds, such as microphones or acceleration sensors. When detecting the biological sound of the subject 1, the biological sound detection device 10 is attached to the subject 1 such that the first sensor 11 is arranged closer to the subject 1 than the second sensor 12 (in other words, the second sensor 12 is arranged at a position farther from the subject 1 than the first sensor 11).

[0025] The first sensor 11 acquires first sound information including the biological sound of the subject 1. The second sensor 12 acquires second sound information including the sounds around the subject 1. Here, the first sound information and the second sound information may be digital audio in, for example, the WAVE format or the like.

[0026] The determination device 20 includes an acquisition unit 21a and 21b, a frequency conversion unit 22a and 22b, a power conversion unit 23a and 23b, a low-frequency acquisition unit 24a and 24b, a correlation coefficient calculation unit 25, a threshold processing unit 26, and a detection unit 27. The acquisition unit 21a acquires the first sound information acquired by the first sensor 11. The acquisition unit 21b acquires the second sound information acquired by the second sensor 12.

[0027] The first sound information acquired by the acquisition unit 21a is sent to the frequency conversion unit 22a. The frequency conversion unit 22a performs frequency conversion processing on the first sound information. The frequency conversion unit 22a sends the first sound information subjected to the frequency conversion processing to the power conversion unit 23a. The power conversion unit 23a performs power conversion processing on the first sound information subjected to the frequency conversion processing. As a result, a power spectrum related to the first sound information (that is, a graph indicating the sound pressure level for each frequency) is generated.

[0028] Similarly, the second sound information acquired by the acquisition unit 21b is sent to the frequency conversion unit 22b. The frequency conversion unit 22b performs a frequency conversion process on the second sound information. The frequency conversion unit 22b sends the second sound information on which the frequency conversion process has been performed to the power conversion unit 23b. The power conversion unit 23b performs a power conversion process on the second sound information on which the frequency conversion process has been performed. As a result, a power spectrum related to the second sound information is generated.

[0029] Note that since various existing modes can be applied to the frequency conversion process and the power conversion process, the description thereof will be omitted.

[0030] The low-frequency acquisition unit 24a acquires (extracts) low-frequency components (for example, components with a frequency of several hundred hertz or less) from the power spectrum related to the first sound information. Similarly, the low-frequency acquisition unit 24b acquires (extracts) low-frequency components from the power spectrum related to the second sound information. The low-frequency components acquired by the low-frequency acquisition unit 24a are referred to as "first low-frequency components". The low-frequency components acquired by the low-frequency acquisition unit 24b are referred to as "second low-frequency components".

[0031] The correlation coefficient calculation unit 25 calculates a correlation coefficient using the first low-frequency component and the second low-frequency component and the following formula.

[0032]

Equation

[0033] Here, "r" is the correlation coefficient, "x i " is the i-th data value of the first low-frequency component, "y i " is the i-th data value of the second low-frequency component, and "n" is the total number of data included in the first and second low-frequency components. "x bar" is the average value of the first low-frequency component, "y bar" is the average value of the second low-frequency component, "s x " is the standard deviation of the first low-frequency component, "s y " is the standard deviation of the second low-frequency component, "s xy " is the covariance of the first and second low-frequency components.

[0034] When the biological sound detection device 10 is properly in contact with the subject 1, for example, the heart sound of the subject 1 (i.e., biological sound) is transmitted to both the first sensor 11 and the second sensor 12. Here, the heart sound mainly consists of low-frequency components of several hundred hertz or less. Therefore, when the biological sound detection device 10 is properly in contact with the subject 1, the components derived from the heart sound are included in both the first and second low-frequency components. As a result, when the biological sound detection device 10 is properly in contact with the subject 1, the above-mentioned correlation coefficient r becomes a relatively large value.

[0035] On the other hand, when the biological sound detection device 10 is not properly in contact with the subject 1, for example, the heart sound of the subject 1 becomes difficult to be transmitted to the first sensor 11 and the second sensor 12. Then, the components derived from the heart sound in each of the first and second low-frequency components become relatively few. As a result, when the biological sound detection device 10 is not properly in contact with the subject 1, the above-mentioned correlation coefficient r becomes a relatively small value.

[0036] The threshold processing unit 26 compares the correlation coefficient r calculated by the correlation coefficient calculation unit 25 with a predetermined threshold. Here, the "predetermined threshold" is a value for determining whether the biological sound detection device 10 is properly in contact with the subject 1, and is set in advance as a fixed value or as a variable value according to some physical quantity or parameter. Such a predetermined threshold may be obtained by experiment or simulation, for example, by obtaining the relationship between the degree of contact of the biological sound detection device 10 with the subject 1 and the correlation coefficient r, and setting it based on the obtained relationship.

[0037] The threshold processing unit 26 sends, for example, information indicating the magnitude relationship between the correlation coefficient r and the predetermined threshold to the detection unit 27. When the correlation coefficient r is smaller than the predetermined threshold, the detection unit 27 determines that the biological sound detection device 10 is not properly in contact with the subject 1. That is, it is determined that the biological sound detection device 10 does not correctly detect the biological sound of the subject 1. Thereby, the detection unit 27 detects an inappropriate contact state of the biological sound detection device 10. In this case, the detection unit 27 issues, for example, a warning sound or displays a warning message. Note that when the correlation coefficient r is larger than the predetermined threshold, the detection unit 27 does not need to perform a special operation.

[0038] The operation of the determination device 20 will be further described with reference to the flowchart of FIG. 2. In the process of step S101 in FIG. 2, the acquisition unit 21a acquires the first sound information acquired by the first sensor 11, and the acquisition unit 21b acquires the second sound information acquired by the second sensor 12. In the process of step S102, the frequency conversion unit 22a performs frequency conversion processing on the first sound information, and the frequency conversion unit 22b performs frequency conversion processing on the second sound information.

[0039] In the process of step S103, the power conversion unit 23a performs power conversion processing on the first sound information subjected to frequency conversion processing, and the power conversion unit 23b performs power conversion processing on the second sound information subjected to frequency conversion processing. In the process of step S104, the low-frequency acquisition unit 24a acquires (extracts) the above-described first low-frequency component, and the low-frequency acquisition unit 24b acquires (extracts) the above-described second low-frequency component.

[0040] In the process of step S105, the correlation coefficient calculation unit 25 calculates the correlation coefficient r. In the process of step S106, the threshold processing unit 26 sends information indicating, for example, the magnitude relationship between the correlation coefficient r and a predetermined threshold to the detection unit 27. In the process of step S107, when the correlation coefficient r is smaller than the predetermined threshold, the detection unit 27 determines that the biological sound detection device 10 is not properly in contact with the subject 1. That is, the detection unit 27 determines that the biological sound detection device 10 is not correctly detecting the biological sound of the subject 1. At this time, since the detection unit 27 has detected an inappropriate contact state of the biological sound detection device 10 (step S107: Yes), for example, it emits a warning sound or displays a warning message (step S108).

[0041] In the process of step S107, when the correlation coefficient r is greater than a predetermined threshold value, the detection unit 27 determines that the biological sound detection device 10 is appropriately in contact with the subject 1. That is, the detection unit 27 determines that the biological sound detection device 10 is correctly detecting the biological sound of the subject 1. In this case, since an inappropriate contact state of the biological sound detection device 10 is not detected (step S107: No), the operation shown in FIG. 2 ends. Note that the operation shown in FIG. 2 is repeatedly performed at a predetermined cycle.

[0042] In this embodiment, "subject 1" corresponds to an example of "target", "acquisition units 21a and 21b" correspond to an example of "acquisition means", "low-frequency acquisition units 24a and 24b" correspond to an example of "extraction means", and "detection unit 27" corresponds to an example of "determination means".

[0043] The present invention is not limited to the above-described embodiments, and can be appropriately modified without departing from the gist or idea of the invention read from the claims and the entire specification. A determination device, a determination method, a computer program, and a recording medium involving such modifications are also included in the technical scope of the present invention.

Explanation of Reference Numerals

[0044] 1... Subject, 10... Biological sound detection device, 11... First sensor, 12... Second sensor, 20... Determination device, 21a, 21b... Acquisition unit, 22a, 22b... Frequency conversion unit, 23a, 23b... Power conversion unit, 24a, 24b... Low-frequency acquisition unit, 25... Correlation coefficient calculation unit, 26... Threshold processing unit, 27... Detection unit

Claims

1. A determination device for determining whether a biological sound detection device having a first sensor that acquires first sound information including the biological sound and a second sensor that is disposed at a position farther from the target than the first sensor and acquires second sound information including sounds around the target correctly detects the biological sound when detecting the biological sound of the target, acquisition means for acquiring the first sound information and the second sound information; extraction means for extracting a first low-frequency component that is a low-frequency component included in the first sound information and extracting a second low-frequency component that is a low-frequency component included in the second sound information; determination means for determining whether the biological sound detection device correctly detects the biological sound based on a comparison result between the first low-frequency component and the second low-frequency component; comprising: the determination means calculates a correlation coefficient between the first low-frequency component and the second low-frequency component, determines that the biological sound detection device does not correctly detect the biological sound when the correlation coefficient is smaller than a predetermined threshold value, and determines that the biological sound detection device correctly detects the biological sound when the correlation coefficient is larger than the predetermined threshold value A determination device characterized by the above.

2. A determination method for determining whether a biological sound detection device having a first sensor that acquires first sound information including the biological sound and a second sensor that is disposed at a position farther from the target than the first sensor and acquires second sound information including sounds around the target correctly detects the biological sound when detecting the biological sound of the target, an acquisition step of acquiring the first sound information and the second sound information; an extraction step of extracting a first low-frequency component that is a low-frequency component included in the first sound information and extracting a second low-frequency component that is a low-frequency component included in the second sound information; a determination step of determining whether the biological sound detection device correctly detects the biological sound based on a comparison result between the first low-frequency component and the second low-frequency component; including: the determination step includes a calculation step of calculating a correlation coefficient between the first low-frequency component and the second low-frequency component, and it is determined that the biological sound detection device does not correctly detect the biological sound when the correlation coefficient is smaller than a predetermined threshold value, and it is determined that the biological sound detection device correctly detects the biological sound when the correlation coefficient is larger than the predetermined threshold value A determination method characterized by the above.

3. When detecting the target biological sound, a computer of a determination device that determines whether a biological sound detection device having a first sensor that acquires first sound information including the biological sound and a second sensor that is disposed at a position farther from the target than the first sensor and acquires second sound information including the sound around the target correctly detects the biological sound, acquisition means for acquiring the first sound information and the second sound information; extraction means for extracting a first low-frequency component that is a low-frequency component included in the first sound information and extracting a second low-frequency component that is a low-frequency component included in the second sound information; including calculation means for calculating a correlation coefficient between the first low-frequency component and the second low-frequency component, determining that the biological sound detection device does not correctly detect the biological sound when the correlation coefficient is smaller than a predetermined threshold, and determining that the biological sound detection device correctly detects the biological sound when the correlation coefficient is larger than the predetermined threshold; determination means; A computer program characterized by causing the computer to function as such.

4. A recording medium, characterized in that the computer program according to claim 3 is recorded thereon.

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