Sensor Unit

Abstract

The inertial sensor of the sensor unit is placed at an appropriate position on the subject. [Solution] The detection device 10 of the sensor unit includes a housing 20, a heart sound sensor 40, and an acceleration sensor 30. The heart sound sensor 40 is attached to the housing 20. The heart sound sensor 40 detects heart sounds, which are sounds produced by the movement of the subject's heart. The acceleration sensor 30 is attached to the housing 20. The acceleration sensor 30 detects acceleration, which is movement of the body surface caused by the movement of the heart.

Description

[Technical Field]

[0001] The present invention relates to a sensor unit. [Background technology]

[0002] The sensor unit of Patent Document 1 includes a housing and an angular velocity sensor. The angular velocity sensor is attached to the housing. The angular velocity sensor is a sensor for detecting body surface movement caused by heart movement of the subject.

[0003] When monitoring a subject's heart using the sensor unit of Patent Document 1, for example, a user of the sensor unit places the housing of the sensor unit on the subject's body surface near the heart while the subject is lying on his / her back. In this state, the sensor unit detects the movement of the subject's heart based on the movement of the subject's body surface detected by the angular velocity sensor. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6619739 Summary of the Invention [Problem to be solved by the invention]

[0005] When monitoring a subject's heart using a sensor unit such as that described in Patent Document 1, it is preferable to place the angular velocity sensor of the sensor unit at an appropriate position on the subject. Specifically, for example, when detecting cardiac movement, it is preferable to place the angular velocity sensor of the sensor unit near the apex of the heart, where movement of the subject's body surface is likely to occur. However, the angular velocity sensor detects various signals corresponding to the movement of each part of the subject's heart. As a result, from the perspective of placing the angular velocity sensor of the sensor unit at an appropriate position, it is difficult for a user of the sensor unit to place the angular velocity sensor of the sensor unit at an appropriate position, even based on the signal detected by the angular velocity sensor. Note that although an angular velocity sensor has been used as an example here, similar issues arise when detecting movement of the subject's body surface using an inertial sensor, not just an angular velocity sensor. [Means for solving the problem]

[0006] The sensor unit for solving the above problem includes a housing, a heart sound sensor attached to the housing and detecting heart sounds, which are sounds generated by the movement of the subject's heart, and an inertial sensor attached to the housing and detecting movement of the body surface generated by the movement of the heart. [Effects of the Invention]

[0007] According to the above configuration, the inertial sensor can be placed at an appropriate position on the subject. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic configuration diagram of a monitoring system according to a first embodiment. [Figure 2] FIG. 2 is a plan view of the detection device according to the first embodiment. [Figure 3] FIG. 3 is an end view of the detection device according to the first embodiment taken along line 3-3 in FIG. [Figure 4] FIG. 4 is an explanatory diagram of a pre-monitoring procedure according to the first embodiment. [Figure 5] FIG. 5 is an explanatory diagram of the heart. [Figure 6] 6(a) is a time chart of heart sounds corresponding to the movement of the heart, and FIG. 6(b) is a time chart of acceleration corresponding to the movement of the heart. [Figure 7] FIG. 7 is a flowchart showing the position identification control according to the first embodiment. [Figure 8] FIG. 8 is a flowchart showing generation control according to the first embodiment. [Figure 9] FIG. 9 is a flowchart showing the calculation control according to the first embodiment. [Figure 10] FIG. 10 is a flowchart showing the abnormality determination control according to the first embodiment. [Figure 11] FIG. 11 is a plan view of the detection device according to the second embodiment. [Figure 12] FIG. 12 is an end view of the detection device according to the second embodiment taken along line 12-12 in FIG. [Figure 13] FIG. 13 is a flowchart showing generation control according to the second embodiment. [Figure 14] FIG. 14 is a plan view of a detection device according to a modified example. [Figure 15] FIG. 15 is a cross-sectional view of a detection device according to a modified example. [Figure 16] FIG. 16 is a plan view of a detection device according to a modified example. [Figure 17] FIG. 17 is a perspective view of a detection device according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0009] First Embodiment <Outline of monitoring system configuration> A first embodiment of the present invention will be described below with reference to Figures 1 to 10. First, a schematic configuration of a monitoring system MS will be described. The monitoring system MS is a system for monitoring cardiac activity of a subject.

[0010] As shown in FIG. 1, the monitoring system MS includes a detection device 10, a control device 60, a computing device 70, an input device 81, and a display 82. As shown in Fig. 2, the detection device 10 includes a housing 20, an acceleration sensor 30, multiple heart sound sensors 40, and multiple light emitters 50. The housing 20 has a generally cylindrical appearance. The housing 20 also has a generally cylindrical space as its internal space. Hereinafter, as shown in Fig. 3, one of the directions along the central axis 20A of the housing 20 will be referred to as a first direction DA. The direction opposite to the first direction DA will be referred to as a second direction DB.

[0011] As shown in FIG. 3, the housing 20 includes a first wall portion 21 and a second wall portion 22. The first wall portion 21 is a wall portion that is located in the first direction DA among the walls that constitute the housing 20. The first wall portion 21 has a generally circular disk shape. The first wall portion 21 includes a first outer surface 21A and a first inner surface 21B. The first outer surface 21A is a surface of the first wall portion 21 that is located in the first direction DA, i.e., a surface that constitutes part of the outer surface of the housing 20. The first inner surface 21B is a surface of the first wall portion 21 that is located in the second direction DB, i.e., a surface that constitutes part of the inner surface of the housing 20.

[0012] The second wall portion 22 is a wall portion that is located in the second direction DB among the walls that constitute the housing 20. The second wall portion 22 has a generally circular plate shape. The second wall portion 22 has a second outer surface 22A and a second inner surface 22B. The second outer surface 22A is the surface of the second wall portion 22 that is located in the second direction DB, i.e., the surface that constitutes part of the outer surface of the housing 20. The second inner surface 22B is the surface of the second wall portion 22 that is located in the first direction DA, i.e., the surface that constitutes part of the inner surface of the housing 20.

[0013] The acceleration sensor 30 is attached to the first wall 21 of the housing 20. The surface of the acceleration sensor 30 in the first direction DA is located on the same plane as the first outer surface 21A of the first wall 21. The acceleration sensor 30 is located on the central axis 20A of the housing 20. The acceleration sensor 30 detects acceleration GA in a predetermined specific direction as body surface movement caused by the movement of the subject's heart. Here, an example of the specific direction is the direction along the central axis 20A of the housing 20. In this embodiment, the acceleration sensor 30 is an example of an inertial sensor that detects body surface movement caused by the movement of the subject's heart. Here, the body surface movement detected by the inertial sensor is vibration, shock, etc. that appear as body surface movement due to the movement of the heart wall, the movement of the heart valves, the movement of blood flowing inside the heart, etc.

[0014] As shown in FIG. 3, the heart sound sensor 40 is attached to the first wall 21 of the housing 20. The surface of the heart sound sensor 40 facing the first direction DA is located on the same plane as the first outer surface 21A of the first wall 21. As shown in FIG. 2, when the detection device 10 is viewed in a direction along the central axis 20A, the multiple heart sound sensors 40 are arranged to surround the acceleration sensor 30. Specifically, the heart sound sensors 40 are arranged at equal intervals in the circumferential direction around the central axis 20A. When the detection device 10 is viewed in a direction along the central axis 20A, the distance between any one heart sound sensor 40 and the acceleration sensor 30 is the same as the distance between any other heart sound sensor 40 and the acceleration sensor 30. In other words, regardless of the relationship between the heart sound sensor 40 and the acceleration sensor 30, the distance between the heart sound sensor 40 and the acceleration sensor 30 is the same. The heart sound sensor 40 detects the heart sound HB, which is a sound generated by the movement of the subject's heart. In this embodiment, the detection device 10 includes eight heart sound sensors 40 .

[0015] As shown in FIG. 3 , the light emitters 50 are attached to the second wall 22 of the housing 20. The light emitters 50 are attached to correspond to the heart sound sensors 40, respectively. Specifically, as shown in FIG. 2 , when the detection device 10 is viewed in a direction along the central axis 20A, the light emitters 50 overlap the corresponding heart sound sensors 40. In other words, the light emitters 50 are attached to the housing 20 at positions adjacent to the corresponding heart sound sensors 40 on the second direction DB side. As such, the concept of "adjacent" does not necessarily mean being in contact. The light emitters 50 also penetrate the second wall 22. Therefore, when the detection device 10 is viewed in the first direction DA, the light emitters 50 are exposed toward the second direction DB from the second wall 22. The surface of the light emitters 50 facing the second direction DB is located on the same plane as the second outer surface 22A of the second wall 22. An example of the light emitters 50 is a light-emitting diode. In this embodiment, the plurality of light emitters 50 are an example of a notification device that issues a notification. That is, in this embodiment, the notification device is configured integrally with the detection device 10.

[0016] 1, the control device 60 is capable of communicating with the detection device 10. Specifically, the control device 60 is capable of communicating with the acceleration sensor 30, the plurality of heart sound sensors 40, and the plurality of light emitters 50. That is, the control device 60 is capable of acquiring information from the acceleration sensor 30 and the plurality of heart sound sensors 40. In this embodiment, the control device 60 is capable of communicating with the detection device 10 via a cable (not shown).

[0017] The control device 60 includes an execution device 61 and a storage device 62. An example of the execution device 61 is a CPU. The storage device 62 includes a read-only ROM, a readable / writable volatile RAM, and a readable / writable non-volatile storage. The storage device 62 stores various programs and data in advance. Specifically, the storage device 62 stores an information processing program 62A as one of the various programs in advance. The execution device 61 executes the information processing program 62A stored in the storage device 62 to perform various processes described below. The execution device 61 stores various information acquired from the detection device 10 in the storage device 62. At this time, the execution device 61 stores information from the acceleration sensor 30 and the multiple heart sound sensors 40 in association with time information in the storage device 62. Therefore, by accessing the storage device 62, the execution device 61 can acquire, for example, information from the acceleration sensor 30 detected at a certain timing and information from the heart sound sensor 40 detected at the same timing in association with each other.

[0018] In this embodiment, the control device 60 is an example of an information processing device that monitors the movement of the heart based on information acquired from the heart sound sensor 40 and the inertial sensor. The detection device 10 and the control device 60 form a sensor unit.

[0019] As shown in FIG. 1, the arithmetic device 70 can communicate with the control device 60. The arithmetic device 70 can communicate with the control device 60 via a cable (not shown). The arithmetic device 70 includes an execution device 71 and a storage device 72. An example of the execution device 71 is a CPU. The storage device 72 includes a read-only ROM, a readable and writable volatile RAM, and a readable and writable non-volatile storage. The storage device 72 stores various programs and various data in advance. The execution device 71 executes various processes by executing the programs stored in the storage device 72. In this embodiment, an example of the arithmetic device 70 is a so-called personal computer.

[0020] 1, the input device 81 can communicate with the arithmetic device 70 via a cable (not shown). The input device 81 is a device for inputting various types of information to the arithmetic device 70. For example, the input device 81 is a keyboard, a pointing device, etc. The display 82 can communicate with the arithmetic device 70 via a cable (not shown). The display 82 is a device for displaying image data output from the arithmetic device 70.

[0021] <Pre-monitoring procedures> Next, with reference to FIG. 4, a preliminary procedure for monitoring the heart of a subject using the monitoring system MS will be described. As shown in FIG. 4, first, a user of the monitoring system MS places the housing 20 on the body surface of the subject near the heart while the subject is lying on his / her back. At this time, the user of the monitoring system MS brings the first outer surface 21A of the housing 20 into contact with the body surface of the subject. The user of the monitoring system MS also places the housing 20 near the apex of the subject's heart. Here, an example of a user of the monitoring system MS is a medical professional such as a doctor. Note that the up-down and left-right directions shown in FIGS. 4 and 5 are directions relative to the body of the subject.

[0022] <About the structure and movement of the heart> Next, the structure and movement of a human heart H, which is a monitoring subject, will be described with reference to FIGS. 5 and 6. As shown in FIG. 5, the heart H includes a right atrium H1A, a right ventricle H2A, a left atrium H3A, and a left ventricle H4A. The heart H also includes a tricuspid valve H1B, a pulmonary valve H2B, a mitral valve H3B, an aortic valve H4B, and an apex H5. When the heart H is functioning normally, blood flowing through various parts of the subject's body flows into the right atrium H1A via the vena cava. Blood in the right atrium H1A flows into the right ventricle H2A via the tricuspid valve H1B. Blood in the right ventricle H2A flows into the lungs via the pulmonary valve H2B and the pulmonary artery. Blood in the lungs flows into the left atrium H3A via the pulmonary vein. Blood in the left atrium H3A flows into the left ventricle H4A via the mitral valve H3B. Blood inside the left ventricle H4A flows to various parts of the subject's body via the aortic valve H4B and the aorta. Sounds and body surface movements caused by such movements of the heart H are likely to be detected near a portion of the heart H located on the lower left side of the subject, i.e., near the apex H5. Therefore, it is preferable for the user of the monitoring system MS to place the housing 20 near the apex H5 of the subject's heart H.

[0023] When the housing 20 is placed near the apex H5 of the subject's heart H and the heart H is moving normally, the acceleration G A detected by the acceleration sensor 30 and the heart sound H B detected by the heart sound sensor 40 change as follows. First, as shown in FIG. 6( a), at time t10, specifically at the closure of the mitral valve H3B, the heart sound H B detected by the heart sound sensor 40 changes significantly. As shown in FIG. 6( b), at time t10, the acceleration G A detected by the acceleration sensor 30 changes slightly. As shown in FIG. 6( b), at a later time t20, specifically at the opening of the aortic valve H4B, the acceleration G A detected by the acceleration sensor 30 changes significantly. As shown in FIG. 6( a), at a later time t30, specifically at the closure of the aortic valve H4B, the heart sound H B detected by the heart sound sensor 40 changes significantly. As shown in FIG. 6( b), at time t30, the acceleration G A detected by the acceleration sensor 30 changes slightly. Thereafter, at time t40, specifically at the opening timing of the mitral valve H3B, the acceleration GA detected by the acceleration sensor 30 changes. Note that in Fig. 6, times t50, t60, t70, and t80 correspond to the closing timing of the mitral valve H3B, the opening timing of the aortic valve H4B, the closing timing of the aortic valve H4B, and the opening timing of the mitral valve H3B.

[0024] <Location control> Next, the position identification control executed by the control device 60 of the monitoring system MS will be described with reference to Fig. 7. This position identification control is a control for identifying an appropriate position where the acceleration sensor 30 of the detection device 10 should be placed. In this embodiment, the execution device 61 of the control device 60 starts the position identification control when the user performs an operation via the input device 81 to request the execution of monitoring.

[0025] As shown in FIG. 7, when the execution device 61 of the control device 60 starts position identification control, it executes the process of step S11. In step S11, the execution device 61 acquires heart sounds HB from the time of the process of step S11 until a predetermined fixed period PA. Specifically, the execution device 61 accesses the storage device 62 to acquire time-series data of multiple heart sounds HB. Here, an example of the fixed period PA is about several seconds. Note that the fixed period PA is predetermined as a period longer than, for example, one cycle of the heartbeat H. In other words, the time-series data of the heart sounds HB includes one or more reasonably loud sounds generated by movements such as the beating of the heart H. In this embodiment, the process of step S11 is a process of acquiring information from multiple heart sound sensors 40. After step S11, the execution device 61 proceeds to step S12.

[0026] In step S12, the execution device 61 identifies the heart sound sensor 40 that detected the loudest heart sound HB based on the time-series data of the multiple heart sounds HB acquired in step S11. Specifically, the execution device 61 identifies the maximum value of the heart sound HB included in each time-series data of the heart sound HB acquired in step S11 as a representative value. Next, the execution device 61 identifies the time-series data of the heart sound HB that includes the largest representative value among the multiple representative values ​​of the heart sound HB. The execution device 61 then identifies the heart sound sensor 40 that detected the identified time-series data of the heart sound HB as the heart sound sensor 40 that detected the loudest heart sound HB. Note that, for example, the heart sound sensor 40 identified by the execution device 61 in step S12 is the heart sound sensor 40 of the multiple heart sound sensors 40 that is located closest to the apex H5 of the heart H. In this embodiment, the processing of step S12 is processing to identify the heart sound sensor 40 that detected the loudest heart sound HB based on information from the multiple heart sound sensors 40. After step S12, the execution device 61 advances the process to step S13.

[0027] In step S13, the execution device 61 identifies the heart sound sensor 40 that detected the quietest heart sound HB based on the multiple time-series data of heart sound HB acquired in step S11. Specifically, for each time-series data of heart sound HB acquired in step S11, the execution device 61 identifies the maximum value of the heart sound HB included in that time-series data as a representative value. Next, the execution device 61 identifies the time-series data of heart sound HB that includes the smallest representative value among the multiple representative values ​​of heart sound HB. The execution device 61 then identifies the heart sound sensor 40 that detected the identified time-series data of heart sound HB as the heart sound sensor 40 that detected the quietest heart sound HB. Note that, for example, the heart sound sensor 40 identified by the execution device 61 in step S13 is the heart sound sensor 40 that is located farthest from the apex H5 of the heart H among the multiple heart sound sensors 40. In this embodiment, the processing of step S13 is processing to identify the heart sound sensor 40 that detected the quietest heart sound HB based on information from the multiple heart sound sensors 40. After step S13, the execution device 61 advances the process to step S14.

[0028] In step S14, the execution unit 61 calculates the absolute value of the difference between the largest representative value obtained in step S12 and the smallest representative value obtained in step S13. In other words, the execution unit 61 calculates the absolute value of the difference between the largest heart sound HB and the smallest heart sound HB. The execution unit 61 then determines whether the absolute value of the calculated difference is less than a predetermined constant difference TA. Here, the constant difference TA is determined, for example, as follows: As described above, when the detection device 10 is viewed in a direction along the central axis 20A, the multiple heart sound sensors 40 are arranged to surround the acceleration sensor 30. As a premise, the smaller the absolute value of the difference, the smaller the variation in the distance between the apex H5 of the heart H and the heart sound sensor 40 for the multiple heart sound sensors 40. Therefore, the smaller the absolute value of the difference, the smaller the distance between the apex H5 of the heart H and the acceleration sensor 30. Therefore, the certain difference TA is determined as a threshold value for determining whether or not the distance between the apex H5 of the heart H and the acceleration sensor 30 is small enough to be permissible. The certain difference TA is determined in advance, for example, through experiments, simulations, etc.

[0029] In step S14, if the execution device 61 determines that the absolute value of the difference is equal to or greater than the given difference TA (S14: NO), the execution device 61 advances the process to step S22. In step S22, the execution device 61 outputs a control signal to the detection device 10 to cause only the light emitter 50 corresponding to the heart sound sensor 40 identified in step S12 to emit light. That is, of the multiple heart sound sensors 40, only the light emitter 50 corresponding to the heart sound sensor 40 that detected the loudest heart sound HB emits light. In this embodiment, the process of step S22 causes some of the multiple light emitters 50, including the light emitter 50 corresponding to the heart sound sensor 40 that detected the loudest heart sound HB, to emit light. In other words, the process of step S22 is an example of a process of reporting the location of the heart sound sensor 40 that detected the loudest heart sound HB by switching the multiple light emitters 50 on and off depending on the location of the heart sound sensor 40 that detected the loudest heart sound HB. The process of step S22 is also an example of a process of reporting the location of the heart sound sensor 40 that detected the loudest heart sound HB by an alarm device. After step S22, the execution device 61 returns to step S11.

[0030] On the other hand, if the execution device 61 determines in step S14 that the absolute value of the difference is less than the certain difference TA (S14: YES), the execution device 61 proceeds to step S21. In other words, if the execution device 61 determines that the distance between the apex H5 of the heart H and the acceleration sensor 30 has decreased to an allowable level, the execution device 61 proceeds to step S21.

[0031] In step S21, the executing device 61 outputs a control signal to the detecting device 10 to cause all of the light emitters 50 to emit light. In this embodiment, the processing of step S21 is processing to cause all of the light emitters 50 to emit light. After step S21, the executing device 61 ends the current position identification control.

[0032] <Monitoring data generation control> Next, referring to Fig. 8, the generation control executed by the control device 60 of the monitoring system MS will be described. This generation control is control for generating data for monitoring. In this embodiment, the execution device 61 of the control device 60 starts the generation control when the position identification control is completed. In other words, the execution device 61 starts the generation control when the detection device 10 is placed in an appropriate position for the subject.

[0033] As shown in FIG. 8, when the execution device 61 of the control device 60 starts generation control, it executes the process of step S31. In step S31, the execution device 61 acquires the heart sound HB and the acceleration GA from the time of the process of step S31 until a predetermined reference period PB. Specifically, the execution device 61 accesses the storage device 62 to acquire time series data of multiple heart sounds HB. The execution device 61 also accesses the storage device 62 to acquire time series data of the acceleration GA. Here, an example of the reference period PB is approximately 10 seconds. The reference period PB is predetermined as a period that includes, for example, multiple cycles of the heartbeat H. After step S31, the execution device 61 proceeds to step S32.

[0034] In step S32, the execution device 61 extracts the time series data of the heart sound HB and the acceleration GA of interest from the time series data of the multiple heart sounds HB and the time series data of the acceleration GA acquired in step S31. Specifically, the execution device 61 extracts the time series data of the heart sound HB detected by the heart sound sensor 40 identified in step S12 from the time series data of the multiple heart sounds HB acquired in step S31 as the time series data of the heart sound HB of interest. In addition, the execution device 61 extracts the time series data of the acceleration GA acquired in step S31 as the time series data of the acceleration GA of interest. After step S32, the execution device 61 proceeds to step S33.

[0035] In step S33, the execution device 61 determines whether the time-series data of the heart sound HB extracted in step S32 satisfies a predetermined precondition. Here, the precondition indicates that the housing 20 of the detection device 10 is placed at an appropriate position on the subject. In this embodiment, the precondition is determined, for example, as follows: As shown in FIG. 6(a), the heart sound HB detected by the heart sound sensor 40 changes significantly at time t10, which is the closure timing of the mitral valve H3B. Therefore, in a situation where movements such as pulsation of the heart H are repeated, the heart sound HB repeatedly becomes louder at the closure timing of the mitral valve H3B and the aortic valve H4B. Therefore, the execution device 61 determines that the precondition is satisfied if the time-series data of the heart sound HB includes multiple time periods during which the heart sound HB is equal to or greater than a predetermined reference value TB. In other words, the precondition indicates that the heart sound HB is repeatedly detected by the heart sound sensor 40 as being equal to or greater than the predetermined reference value TB. In this embodiment, the reference value TB is a value that is a certain value smaller than the heart sound HB that is expected to be detected by the heart sound sensor 40 at the timing of closure of the mitral valve H3B when the detection device 10 is placed at an appropriate position on the subject. Therefore, if the state in which the housing 20 of the detection device 10 is placed at an appropriate position on the subject continues over the reference period PB, the execution device 61 determines that the precondition is met. Note that the reference value TB is determined in advance, for example, through experiments, simulations, etc. In this embodiment, the processing of step S33 is an example of processing for determining whether the information from the heart sound sensor 40 satisfies the precondition.

[0036] As shown in FIG. 8, if the execution device 61 determines in step S33 that the time-series data of the heart sound HB extracted in step S32 does not satisfy the preconditions (S33: NO), the execution device 61 returns to step S31.

[0037] On the one hand, in step S33 described above, when the execution device 61 determines that the time series data of the heart sound HB extracted in step S32 satisfies the preconditions (S33: YES), the execution device 61 proceeds to step S34. In other words, the execution device 61 executes the processing after step S34 on the condition that it is determined that the information from the heart sound sensor 40 satisfies the preconditions.

[0038] In step S34, the execution device 61 generates target data to be monitored based on the time series data of the heart sound HB and the acceleration GA extracted in step S32. In the present embodiment, first, the execution device 61 analyzes the time series data of the heart sound HB and the acceleration GA extracted in step S32 to identify the closing timing of the mitral valve H3B included in the time series data. Then, the execution device 61 generates, as the target data to be monitored, the time series data after the second closing timing of the mitral valve H3B among the time series data of the heart sound HB and the acceleration GA extracted in step S32. After step S34, the execution device 61 ends the current generation control.

[0039] <Calculation control of LVET> Next, referring to FIG. 9, the calculation control executed by the control device 60 of the monitoring system MS will be described. This calculation control is for calculating the ejection period PR, which is the period from the opening timing of the aortic valve H4B to the closing timing of the aortic valve H4B, that is, so-called LVET, as part of the monitoring. Here, LVET is an abbreviation for Left Ventricle Ejection Time. Incidentally, LVET is also referred to as the left ventricular ejection time. In the present embodiment, after the execution device 61 of the control device 60 finishes the generation control, it starts the calculation control.

[0040] As shown in FIG. 9, when the execution unit 61 of the control device 60 starts calculation control, it executes the process of step S51. In step S51, the execution unit 61 identifies the opening timing of the aortic valve H4B by analyzing the target data generated in step S34. As shown in FIG. 6(b), the acceleration G A detected by the acceleration sensor 30 changes at time t20, which is the opening timing of the aortic valve H4B. In other words, the sensitivity of the acceleration sensor 30 to the opening timing of the aortic valve H4B tends to be higher than the sensitivity of the heart sound sensor 40 to the opening timing of the aortic valve H4B. Therefore, the execution unit 61 identifies the opening timing of the aortic valve H4B based on the acceleration G A of the target data generated in step S34. In this embodiment, the process of step S51 is a process of identifying the opening timing of the aortic valve H4B based on information acquired from the inertial sensor. As shown in FIG. 9, after step S51, the execution unit 61 proceeds to step S52.

[0041] In step S52, the execution device 61 identifies the closing timing of the aortic valve H4B by analyzing the target data generated in step S34. As shown in FIG. 6A, the heart sound HB detected by the heart sound sensor 40 changes significantly at time t30, which is the closing timing of the aortic valve H4B. In other words, the sensitivity of the heart sound sensor 40 to the closing timing of the aortic valve H4B tends to be higher than the sensitivity of the acceleration sensor 30 to the closing timing of the aortic valve H4B. Therefore, the execution device 61 identifies the closing timing of the aortic valve H4B based on the heart sound HB in the target data generated in step S34. In this embodiment, the processing of step S52 is processing for identifying the closing timing of the aortic valve H4B based on information acquired from the heart sound sensor 40. As shown in FIG. 9, after step S52, the execution device 61 proceeds to step S53.

[0042] In step S53, the executing unit 61 calculates the release period PR based on the release timing of the aortic valve H4B identified in step S51 and the closing timing of the aortic valve H4B identified in step S52. For example, the executing unit 61 calculates the absolute value of the difference between time t20 and time t30 in FIG. 6 as the release period PR. In this embodiment, the process from step S51 onwards to step S53 onwards is one of monitoring processes based on information acquired from the heart sound sensor 40 and the inertial sensor. As shown in FIG. 9, after step S53, the executing unit 61 ends the current calculation control.

[0043] <Abnormality detection control> Next, abnormality determination control executed by the control device 60 of the monitoring system MS will be described with reference to Fig. 10. This abnormality determination control is a control for determining the presence or absence of an abnormality in the subject's heart H, etc., as part of monitoring. In this embodiment, the execution device 61 of the control device 60 starts the abnormality determination control after completing the calculation control.

[0044] As shown in FIG. 10, when the execution device 61 of the control device 60 starts the abnormality determination control, it executes the process of step S71. In step S71, the execution device 61 determines whether or not audible noise is occurring based on the time-series data of the heart sound HB of the target data generated in step S34. Specifically, the execution device 61 determines whether or not there is a predetermined noise value TC or greater over a predetermined period PC based on the time-series data of the heart sound HB of the target data. As a premise, as shown in FIG. 6(a), in a situation where there is no abnormality in the subject's body, the heart sound HB detected by the heart sound sensor 40 becomes quiet at times other than when the mitral valve H3B of the heart H or the aortic valve H4B of the heart H closes. On the other hand, if there is some abnormality in the subject's respiratory system, the heart sound HB detected by the heart sound sensor 40 continues to become louder even at times when the actual heart sound H is quiet. Therefore, for example, the predetermined value TC is a value that is a certain value greater than the heart sound HB that is expected to be detected by the heart sound sensor 40 at timings other than the closing timing of the mitral valve H3B and the aortic valve H4B when there is no abnormality in the subject's body. Furthermore, for example, the predetermined period PC is a period that is longer than the period required for the mitral valve H3B to close and also longer than the period required for the aortic valve H4B to close. The predetermined period PC and the predetermined value TC are determined in advance through experiments, simulations, etc. In this embodiment, the process of step S71 is a process of determining, based on information from the heart sound sensor 40, whether or not there is noise equal to or greater than the predetermined value TC over the predetermined period PC.

[0045] 10, if the executing device 61 determines in step S71 that there is noise of a predetermined value TC or more over the predetermined period PC (S71: YES), the executing device 61 proceeds to step S81. In other words, the executing device 61 proceeds to step S81 on the condition that it has been determined that there is noise of a predetermined value TC or more over the predetermined period PC.

[0046] In step S81, the executing device 61 determines that there is an abnormality in the respiratory system of the subject. Then, the executing device 61 outputs a control signal to the display 82 via the computing device 70, thereby notifying the display 82 that there is an abnormality in the respiratory system of the subject. After step S81, the executing device 61 ends the current abnormality determination control.

[0047] On the other hand, in step S71 described above, if the executing device 61 does not determine that there is noise equal to or greater than the predetermined value TC over the predetermined period PC (S71: NO), the executing device 61 proceeds to step S72. In other words, the executing device 61 performs one of the processes of steps S82, S83, S84, and S85 described below, with the necessary condition being that it is not determined that there is noise equal to or greater than the predetermined value TC over the predetermined period PC.

[0048] In step S72, the execution unit 61 analyzes the target data generated in step S34 to identify the opening timing of the aortic valve H4B. The process of identifying the opening timing of the aortic valve H4B is the same as that of step S51. Next, the execution unit 61 acquires the heart sound HB at the opening timing of the aortic valve H4B based on the time-series data of the heart sound HB in the target data generated in step S34. The execution unit 61 then determines whether the heart sound HB at the opening timing of the aortic valve H4B is equal to or greater than a predetermined first threshold value TD1. Here, the first threshold value TD1 is, for example, a value that is a certain value greater than the heart sound HB that is expected to be detected by the heart sound sensor 40 at the opening timing of the aortic valve H4B in a state where there is no abnormality in the subject's body. The first threshold value TD1 is determined in advance through experiments, simulations, and the like. In this embodiment, the process of step S72 includes a process of identifying the opening timing of the aortic valve H4B based on information from the inertial sensor. The process of step S72 also includes a process of acquiring the heart sound HB at the timing of the aortic valve H4B opening based on information from the heart sound sensor 40. Furthermore, the process of step S72 includes a process of determining whether the heart sound HB at the timing of the aortic valve H4B opening is equal to or greater than a predetermined first set value TD1.

[0049] In step S72, if the execution device 61 determines that the heart sound HB at the timing of opening of the aortic valve H4B is equal to or greater than the first specified value TD1 (S72: YES), the execution device 61 proceeds to step S73. In other words, the execution device 61 performs one of steps S82 and S83, which will be described later, on the condition that the heart sound HB at the timing of opening of the aortic valve H4B is equal to or greater than the first specified value TD1.

[0050] In step S73, the execution device 61 identifies the release timing of the mitral valve H3B by analyzing the target data generated in step S34. As shown in FIG. 6B, the acceleration GA detected by the acceleration sensor 30 changes at time t40, which is the release timing of the mitral valve H3B. In other words, the sensitivity of the acceleration sensor 30 to the release timing of the mitral valve H3B tends to be higher than the sensitivity of the heart sound sensor 40 to the release timing of the mitral valve H3B. Therefore, the execution device 61 identifies the release timing of the mitral valve H3B based on the acceleration GA of the target data generated in step S34. Next, the execution device 61 acquires the heart sound HB at the release timing of the mitral valve H3B based on the time-series data of the heart sound HB of the target data generated in step S34. Then, the execution device 61 determines whether the heart sound HB at the release timing of the mitral valve H3B is equal to or greater than a predetermined second specified value TD2. Here, the second specified value TD2 is, for example, a value that is a certain value greater than the heart sound HB that is expected to be detected by the heart sound sensor 40 at the opening timing of the mitral valve H3B when there is no abnormality in the subject's body. The second specified value TD2 is determined in advance through experiments, simulations, etc. In this embodiment, the process of step S73 includes a process of identifying the opening timing of the mitral valve H3B based on information from the inertial sensor. The process of step S73 also includes a process of acquiring the heart sound HB at the opening timing of the mitral valve H3B based on information from the heart sound sensor 40. The process of step S73 further includes a process of determining whether the heart sound HB at the opening timing of the mitral valve H3B is equal to or greater than the predetermined second specified value TD2.

[0051] 10, if the execution device 61 determines in step S73 that the heart sound HB at the opening timing of the mitral valve H3B is equal to or greater than the second specified value TD2 (S73: YES), the execution device 61 proceeds to step S82. In other words, the execution device 61 performs the process of step S82 with the necessary condition being that the heart sound HB at the opening timing of the mitral valve H3B is equal to or greater than the second specified value TD2.

[0052] In step S82, the executing unit 61 determines that the subject has an abnormality in the aortic valve H4B and the mitral valve H3B. Then, the executing unit 61 outputs a control signal to the display 82 via the computing device 70, thereby notifying the display 82 that the subject has an abnormality in the aortic valve H4B and the mitral valve H3B. After step S82, the executing unit 61 ends the current abnormality determination control.

[0053] On the other hand, if the execution unit 61 determines in step S73 that the heart sound HB at the opening timing of the mitral valve H3B is less than the second specified value TD2 (S73: NO), the execution unit 61 proceeds to step S83.

[0054] In step S83, the executing unit 61 determines that the subject has an abnormality in the aortic valve H4B. Then, the executing unit 61 outputs a control signal to the display 82 via the computing device 70, thereby notifying the display 82 that the subject has an abnormality in the aortic valve H4B. After step S83, the executing unit 61 ends the current abnormality determination control.

[0055] On the other hand, if the execution unit 61 determines in step S72 that the heart sound HB at the timing of opening of the aortic valve H4B is less than the first specified value TD1 (S72: NO), the execution unit 61 proceeds to step S74.

[0056] In step S74, the execution device 61 determines whether the heart sound HB at the release timing of the mitral valve H3B is equal to or greater than a predetermined second specified value TD2, similar to the process of step S73 described above. That is, the process of step S74 includes a process of identifying the release timing of the mitral valve H3B based on information from the inertial sensor. The process of step S74 also includes a process of acquiring the heart sound HB at the release timing of the mitral valve H3B based on information from the heart sound sensor 40. The process of step S74 further includes a process of determining whether the heart sound HB at the release timing of the mitral valve H3B is equal to or greater than a predetermined second specified value TD2.

[0057] In step S74, if the execution device 61 determines that the heart sound HB at the opening timing of the mitral valve H3B is equal to or greater than the second specified value TD2 (S74: YES), the execution device 61 proceeds to step S84. In other words, the execution device 61 performs the process of step S84 with the necessary condition being that the heart sound HB at the opening timing of the mitral valve H3B is equal to or greater than the second specified value TD2.

[0058] In step S84, the executing unit 61 determines that there is an abnormality in the mitral valve H3B of the subject. Then, the executing unit 61 notifies the display 82 that there is an abnormality in the mitral valve H3B of the subject by outputting a control signal to the display 82 via the computing device 70. After step S84, the executing unit 61 ends the current abnormality determination control.

[0059] On the other hand, if the execution unit 61 determines in step S74 that the heart sound HB at the opening timing of the mitral valve H3B is less than the second specified value TD2 (S74: NO), the execution unit 61 proceeds to step S85.

[0060] In step S85, the executing unit 61 determines that the subject has no abnormality. Then, the executing unit 61 outputs a control signal to the display 82 via the computing device 70, thereby notifying the display 82 that the subject's respiratory system, aortic valve H4B, and mitral valve H3B are normal. After step S85, the executing unit 61 ends the current abnormality determination control.

[0061] <Operation of this embodiment> As shown in Fig. 4, a user of the monitoring system MS places the detection device 10 on the body surface of the subject lying on their back, near the heart H. Here, the acceleration GA detected by the acceleration sensor 30 changes in a complex manner depending on the movements of various parts of the subject's heart H. As a result, it is difficult to determine, based on the acceleration GA detected by the acceleration sensor 30, whether the acceleration sensor 30 of the detection device 10 is in an appropriate position on the subject, specifically, whether the acceleration sensor 30 of the detection device 10 is approaching the apex H5 of the heart. On the other hand, the closer the detection device 10 is to the appropriate position on the subject, the louder the heart sound HB detected by the heart sound sensor 40 tends to be.

[0062] <Effects of this embodiment> (1-1) As shown in FIG. 3 , in this embodiment, the detection device 10 includes a heart sound sensor 40 in addition to the acceleration sensor 30. Therefore, a user of the monitoring system MS can determine the appropriate position for placing the acceleration sensor 30 based on the magnitude of the heart sound HB detected by the heart sound sensor 40. Therefore, for example, a user of the monitoring system MS can place the detection device 10 at an appropriate position on the subject by moving the housing 20 of the detection device 10 relative to the subject based on the magnitude of the heart sound HB detected by the heart sound sensor 40. In other words, the acceleration sensor 30 of the detection device 10 can be placed at an appropriate position on the subject. Note that the acceleration sensor 30 can detect various movements of the heart H compared to the heart sound sensor 40, and therefore the detection device 10 including the acceleration sensor 30 and the heart sound sensor 40 can detect detailed movements of the heart H when monitoring the heart H.

[0063] (1-2) When a user of the monitoring system MS performs an operation to request the execution of monitoring via the input device 81, the execution device 61 of the control device 60 starts position identification control, as shown in FIG. 7. In step S11, the execution device 61 acquires time-series data of multiple heart sounds HB from the time of processing in step S11 until a predetermined fixed period PA before. In step S12, the execution device 61 identifies the heart sound sensor 40 that detected the loudest heart sound HB based on the time-series data of the multiple heart sounds HB acquired in step S11. In step S13, the execution device 61 identifies the heart sound sensor 40 that detected the quietest heart sound HB based on the time-series data of the multiple heart sounds HB acquired in step S11. In step S14, the execution device 61 calculates the absolute value of the difference between the loudest heart sound HB in step S12 and the quietest heart sound HB in step S13. The execution device 61 then determines whether the absolute value of the calculated difference is less than a predetermined fixed difference TA. In step S14, if the execution device 61 determines that the absolute value of the difference is equal to or greater than the certain difference TA (S14: NO), the execution device 61 proceeds to step S22. In step S22, the execution device 61 outputs a control signal to the detection device 10, thereby causing only the light emitter 50 corresponding to the heart sound sensor 40 identified in step S12 to emit light. In other words, only the light emitter 50 corresponding to the heart sound sensor 40 that detected the loudest heart sound HB among the multiple heart sound sensors 40 emits light.

[0064] To put the process of step S22 described above in other words, in step S22, the executing device 61 notifies the position of the heart sound sensor 40 that detected the loudest heart sound HB via the notification device. This allows, for example, the user of the monitoring system MS to know the position of the heart sound sensor 40 that detected the loudest heart sound HB via the multiple light emitters 50 that serve as notification devices. Therefore, the user of the monitoring system MS can place the detection device 10 in an appropriate position based on the information from the notification device.

[0065] (1-3) As shown in Fig. 2, the notification device is a plurality of light emitters 50 corresponding to the plurality of heart sound sensors 40. The light emitters 50 are attached to the housing 20 at positions adjacent to the corresponding heart sound sensors 40. Then, as shown in Fig. 7, in step S22, the execution device 61 notifies the position of the heart sound sensor 40 that detected the loudest heart sound HB by switching on and off each of the plurality of light emitters 50 depending on the position of the heart sound sensor 40 that detected the loudest heart sound HB. This allows, for example, when a user of the monitoring system MS holds and moves the detection device 10, the user can check information from the plurality of light emitters 50 while keeping the housing 20 of the detection device 10 that is being moved in their field of view.

[0066] (1-4) As shown in Fig. 7, in step S22, the executing device 61 outputs a control signal to the detecting device 10 to cause some of the light emitters 50, including the light emitter 50 corresponding to the heart sound sensor 40 that detected the loudest heart sound HB, to emit light. This allows, for example, a user of the monitoring system MS to intuitively grasp the position of the heart sound sensor 40 that detected the loudest heart sound HB.

[0067] (1-5) As shown in FIG. 7 , if the execution device 61 determines in step S14 that the absolute value of the difference between the loudest heart sound HB and the quietest heart sound HB is less than the certain difference TA (S14: YES), the execution device 61 proceeds to step S21. In step S21, the execution device 61 outputs a control signal to the detection device 10 to cause all of the light emitters 50 to emit light. According to this embodiment, if the absolute value of the difference is equal to or greater than the certain difference TA—in other words, if the detection device 10 is not positioned appropriately—some of the light emitters 50, including the light emitter 50 corresponding to the heart sound sensor 40 that detected the loudest heart sound HB, emit light. On the other hand, if the absolute value of the difference is less than the certain difference TA—in other words, if the detection device 10 is positioned appropriately—all of the light emitters 50 emit light. This allows, for example, a user of the monitoring system MS to know that the detection device 10 is positioned appropriately.

[0068] (1-6) As shown in FIG. 1, the monitoring system MS includes a heart sound sensor 40, an acceleration sensor 30, and a control device 60. The control device 60 monitors the movement of the heart H based on information acquired from the heart sound sensor 40 and the acceleration sensor 30. With this configuration, the control device 60 monitors the subject's heart H based on information from the heart sound sensor 40 in addition to information from the acceleration sensor 30, which serves as an inertial sensor. This allows for more detailed monitoring than when monitoring is based only on information from the acceleration sensor 30, for example.

[0069] (1-7) When the position identification control is completed, the execution device 61 starts control for generating monitoring data. As shown in FIG. 8 , in step S33, the execution device 61 determines whether the time-series data of the heart sound HB extracted in step S32 satisfies a predetermined precondition. Here, the precondition indicates that the housing 20 of the detection device 10 is placed in an appropriate position on the subject. Then, in step S33, the execution device 61 executes the processing from step S34 onward, assuming that the information from the heart sound sensor 40 satisfies the precondition. In other words, the execution device 61 performs monitoring, specifically, calculation control and abnormality detection control, based on the information from the heart sound sensor 40 and the acceleration sensor 30, assuming that the information from the heart sound sensor 40 satisfies the precondition. As described above, in terms of determining whether the detection device 10 is placed in an appropriate position on the subject, it is preferable to use the heart sound HB detected by the heart sound sensor 40 rather than the acceleration GA detected by the acceleration sensor 30. Therefore, the execution device 61 can determine, through the determination in step S33, whether the acquired time-series data from the heart sound sensor 40 and the acceleration sensor 30 is time-series data acquired when the detection device 10 is placed in an appropriate position on the subject. Then, the execution device 61 can perform monitoring based on the time-series data acquired when the housing 20 of the detection device 10 is placed in an appropriate position on the subject. Note that if the execution device 61 performs monitoring in this manner, it is possible to prevent monitoring from being performed based on time-series data acquired when, for example, the housing 20 of the detection device 10 is not placed in an appropriate position.

[0070] (1-8) For example, when the detection device 10 is placed in an appropriate position on the subject, the heart sound sensor 40 detects a relatively loud sound in response to the movement of the heart H. In this regard, a prerequisite for step S33 is that the heart sound sensor 40 repeatedly detects a heart sound HB equal to or greater than a predetermined reference value TB. Therefore, the execution unit 61 can more reliably perform monitoring based on time-series data acquired when the detection device 10 is placed in an appropriate position.

[0071] (1-9) After completing the control of generating monitoring data, the execution unit 61 of the control device 60 starts the control of calculating the LVET. As shown in FIG. 9, in step S51, the execution unit 61 determines the opening timing of the aortic valve H4B based on the acceleration GA of the target data generated in step S34, i.e., based on information acquired from the acceleration sensor 30 serving as an inertial sensor. In step S52, the execution unit 61 determines the closing timing of the aortic valve H4B based on the heart sounds HB of the target data generated in step S34, i.e., based on information acquired from the heart sound sensor 40. In step S53, the execution unit 61 calculates the opening period PR, which is the period from the opening timing of the aortic valve H4B to the closing timing of the aortic valve H4B, based on the opening timing and closing timing of the aortic valve H4B. Here, as shown in FIG. 6, the sensitivity of the acceleration sensor 30 to the opening timing of the aortic valve H4B tends to be higher than the sensitivity of the heart sound sensor 40 to the opening timing of the aortic valve H4B. Furthermore, the sensitivity of the heart sound sensor 40 to the closing timing of the aortic valve H4B tends to be higher than the sensitivity of the acceleration sensor 30 to the closing timing of the aortic valve H4B. With the above configuration, it is possible to accurately identify the opening timing and closing timing of the aortic valve H4B by utilizing the respective characteristics of the acceleration sensor 30 and the heart sound sensor 40. As a result, it is possible to accurately calculate the opening period PR, which is the period from the opening timing of the aortic valve H4B to the closing timing of the aortic valve H4B, i.e., the LVET, which is an index value for diagnosing the state of movement of the aortic valve H4B.

[0072] (1-10) After completing the calculation control, the execution unit 61 of the control device 60 starts the abnormality determination control. As shown in FIG. 10, in step S71, the execution unit 61 determines whether or not there is noise equal to or greater than a predetermined value Tc over a predetermined period Pc based on information from the heart sound sensor 40. If the execution unit 61 determines in step S71 that there is noise equal to or greater than the predetermined value Tc over the predetermined period Pc (S71: YES), the execution unit 61 proceeds to step S81. In step S81, the execution unit 61 determines that there is an abnormality in the subject's respiratory system. For example, if there is some abnormality in the subject's respiratory system, continuous noise is detected by the heart sound sensor 40 regardless of the movement of the heart H. According to the above configuration, if there is noise equal to or greater than the predetermined value Tc over the predetermined period Pc, that is, if there is some abnormality in the subject's respiratory system, it can be determined that there is an abnormality in the subject's respiratory system.

[0073] (1-11) In step S72, the execution unit 61 identifies the opening timing of the aortic valve H4B based on information from the acceleration sensor 30, which serves as an inertial sensor. The execution unit 61 also acquires the heart sound HB at the opening timing of the aortic valve H4B based on information from the heart sound sensor 40. The execution unit 61 then determines whether the heart sound HB at the opening timing of the aortic valve H4B is equal to or greater than a predetermined first specified value TD1. If the execution unit 61 determines that the heart sound HB at the opening timing of the aortic valve H4B is equal to or greater than the first specified value TD1, it determines in step S82 or the like that there is an abnormality in the aortic valve H4B of the subject. Generally, the heart sound HB generated at the opening timing of the aortic valve H4B is relatively small. However, if there is some abnormality in the aortic valve H4B, a relatively large heart sound HB will be generated at the opening timing of the aortic valve H4B. According to the above configuration, if it is determined that the heart sound HB at the timing when the aortic valve H4B opens is equal to or greater than the first specified value TD1, that is, if there is some abnormality in the aortic valve H4B, it can be determined that there is an abnormality in the aortic valve H4B.

[0074] (1-12) In step S71, the executing device 61 executes the process of step S72 on the condition that it has not determined that there is noise equal to or greater than the predetermined value TC over the predetermined period PC. That is, if the executing device 61 has not determined that there is noise equal to or greater than the predetermined value TC over the predetermined period PC and has determined that the heart sound HB at the timing of opening of the aortic valve H4B is equal to or greater than the first specified value TD1, it determines that there is an abnormality in the aortic valve H4B of the subject in step S82, etc. This makes it possible to prevent, for example, a situation in which there is some abnormality in the respiratory system of the subject, that is, when continuous noise is detected by the heart sound sensor 40, from being erroneously determined to be an abnormality in the aortic valve H4B of the subject due to the continuous noise.

[0075] (1-13) In step S73, the execution device 61 identifies the release timing of the mitral valve H3B based on information from the acceleration sensor 30, which serves as an inertial sensor. The execution device 61 also acquires the heart sound HB at the release timing of the mitral valve H3B based on information from the heart sound sensor 40. Furthermore, the execution device 61 determines whether the heart sound HB at the release timing of the mitral valve H3B is equal to or greater than a predetermined second specified value TD2. If the execution device 61 determines that the heart sound HB at the release timing of the mitral valve H3B is equal to or greater than the second specified value TD2, it determines in step S82 or the like that there is an abnormality in the mitral valve H3B of the subject. Generally, the heart sound HB generated at the release timing of the mitral valve H3B is relatively small. However, if there is some abnormality in the mitral valve H3B, a relatively large heart sound HB is generated at the release timing of the mitral valve H3B. According to the above configuration, if it is determined that the heart sound HB at the timing of opening of the mitral valve H3B is equal to or greater than the second specified value TD2, that is, if there is some abnormality in the mitral valve H3B, it can be determined that there is an abnormality in the mitral valve H3B. Note that the processes in steps S74 and S84 also have the same effect as above.

[0076] (1-14) In step S71, the executing device 61 executes the processing of step S73 and the like, with the necessary condition that it is not determined that there is noise equal to or greater than the predetermined value TC over the predetermined period PC. That is, if the executing device 61 does not determine that there is noise equal to or greater than the predetermined value TC over the predetermined period PC and determines that the heart sound HB at the opening timing of the mitral valve H3B is equal to or greater than the second specified value TD2, it determines that there is an abnormality in the mitral valve H3B of the subject in step S82 and the like. This makes it possible to prevent, for example, a situation in which there is some abnormality in the respiratory system of the subject, that is, when continuous noise is detected by the heart sound sensor 40, from being erroneously determined to be an abnormality in the mitral valve H3B of the subject due to the continuous noise.

[0077] Second Embodiment A second embodiment of the present invention will be described below with reference to FIGS. 11 to 13. In the second embodiment, the configuration of the monitoring system MS is partially different from that of the first embodiment. Specifically, the monitoring system MS of the second embodiment includes a detection device 110 instead of the detection device 10. In addition, in the second embodiment, some of the various controls are different from those of the first embodiment. Specifically, in the second embodiment, position identification control is not performed. In addition, in the second embodiment, some of the processing of the generation control is different from that of the first embodiment. Note that the description of the second embodiment will focus on the differences from the first embodiment, and the same components as those in the first embodiment will be denoted by the same reference numerals, and the description will be omitted or simplified.

[0078] <Outline of monitoring system configuration> As shown in Fig. 11, the detection device 110 includes a housing 20, a plurality of acceleration sensors 30, and a plurality of heart sound sensors 40. In this embodiment, the detection device 110 includes a total of 12 acceleration sensors 30. The detection device 110 also includes a total of 12 heart sound sensors 40. Note that in Figs. 11 and 12, of the acceleration sensors 30 and heart sound sensors 40, the heart sound sensors 40 are indicated by dots. The detection device 110 does not include a light emitter 50.

[0079] Here, a set of one heart sound sensor 40 and one acceleration sensor 30 adjacent to the heart sound sensor 40 is referred to as a set sensor. In this embodiment, the detection device 110 includes a total of 12 sets of set sensors.

[0080] 12, the acceleration sensor 30 is attached to the first wall 21 of the housing 20. The surface of the acceleration sensor 30 facing in the first direction DA is located on the same plane as the first outer surface 21A of the first wall 21. The heart sound sensor 40 is attached to the first wall 21 of the housing 20. The surface of the heart sound sensor 40 facing in the first direction DA is located on the same plane as the first outer surface 21A of the first wall 21.

[0081] As shown in FIG. 11 , when the detection device 110 is viewed in a direction along the central axis 20A of the housing 20, four of the twelve sets of sensors are arranged to surround the central axis 20A. In this embodiment, when the detection device 110 is viewed in a direction along the central axis 20A, for the four sets of sensors, the distance between the central axis 20A and any acceleration sensor 30 is the same as the distance between the central axis 20A and any heart sound sensor 40. Note that for the four sets of sensors, the acceleration sensors 30 and the heart sound sensors 40 are arranged alternately around the central axis 20A. Furthermore, when the detection device 110 is viewed in a direction along the central axis 20A, the remaining eight sets of sensors, excluding the four sets of sensors, out of the twelve sets of sensors, are arranged to surround the four sets of sensors. In this embodiment, when the detection device 110 is viewed in a direction along the central axis 20A, for the eight sensor pairs described above, the distance between the central axis 20A and any acceleration sensor 30 is the same as the distance between the central axis 20A and any heart sound sensor 40. Note that for the eight sensor pairs described above, the acceleration sensors 30 and heart sound sensors 40 are arranged alternately around the central axis 20A.

[0082] <Generation control> Next, the generation control executed by the control device 60 of the monitoring system MS will be described with reference to Fig. 13. This generation control is control for generating data for monitoring. In this embodiment, the execution device 61 of the control device 60 starts the generation control when the user performs an operation to request the execution of monitoring via the input device 81. Note that, for example, the situation in which the generation control is started is a situation in which the user of the monitoring system MS places the housing 20 of the detection device 110 near the apex H5 of the heart H of the subject.

[0083] As shown in FIG. 13 , when the execution device 61 of the control device 60 starts generation control, it executes the process of step S131. In step S131, the execution device 61 acquires the heart sound HB and the acceleration GA from the time of the process of step S131 until a predetermined reference period PB. Specifically, the execution device 61 accesses the storage device 62 to acquire time-series data of multiple heart sounds HB. The execution device 61 also accesses the storage device 62 to acquire time-series data of multiple accelerations GA. Here, an example of the reference period PB is approximately 10 seconds. The reference period PB is predetermined as a period that includes, for example, multiple cycles of the heartbeat H. In this embodiment, the process of step S131 is an example of a process of acquiring information from multiple heart sound sensors 40. After step S131, the execution device 61 proceeds to step S132.

[0084] In step S132, the execution device 61 extracts the target time series data of the heart sound HB and acceleration GA from the multiple time series data of the heart sound HB and the multiple time series data of the acceleration GA acquired in step S131. Specifically, first, for each time series data of the heart sound HB acquired in step S131, the execution device 61 identifies the maximum value of the heart sound HB included in that time series data as a representative value. Next, the execution device 61 identifies the time series data of the heart sound HB containing the largest representative value among the multiple representative values ​​of the heart sound HB. Furthermore, the execution device 61 identifies the heart sound sensor 40 that detected the identified time series data of the heart sound HB as the heart sound sensor 40 that detected the loudest heart sound HB. Next, the execution device 61 identifies the acceleration sensor 30 paired with the heart sound sensor 40 that detected the loudest heart sound HB. The execution device 61 then extracts the time series data from the heart sound sensor 40 and acceleration sensor 30 identified as above as information of the paired sensor placed at an appropriate position on the subject. For example, the heart sound sensor 40 identified by the execution device 61 as described above is the heart sound sensor 40 that is located closest to the apex H5 of the heart H among the multiple heart sound sensors 40. In this embodiment, the process of step S132 includes a process of identifying the heart sound sensor 40 that detected the loudest heart sound HB based on information from the multiple heart sound sensors 40. The process of step S132 also includes a process of extracting information from the heart sound sensor 40 that detected the loudest heart sound HB and information from the acceleration sensor 30 paired with that heart sound sensor 40 as information from a paired sensor located in an appropriate position. After step S132, the execution device 61 proceeds to step S33. The execution device 61 then executes step S33 and subsequent steps. Note that the process from step S33 onward is similar to that of the first embodiment, and therefore will not be described again.

[0085] <Effects of this embodiment> In addition to the above advantages (1-1), (1-6) to (1-14), the present embodiment also provides the following advantages (2-1) and (2-2).

[0086] (2-1) As shown in FIG. 11 , the detection device 110 includes a plurality of sensor pairs. Each sensor pair includes a heart sound sensor 40 and an acceleration sensor 30 adjacent to the heart sound sensor 40. For example, suppose that a user of the monitoring system MS places the detection device 110 near what is estimated to be the apex H5 of the heart H on the body surface of the subject. In this case, there is a high probability that one of the sensor pairs included in the detection device 110 will actually be placed near the apex H5. This reduces the effort required to adjust the position of the detection device 110 relative to the subject, and allows one of the sensor pairs included in the detection device 110 to be placed at an appropriate position on the subject.

[0087] (2-2) The execution device 61 of the control device 60 starts generation control when the user performs an operation via the input device 81 to request the execution of monitoring. As shown in FIG. 13 , in step S131, the execution device 61 acquires time-series data of multiple heart sounds HB and multiple time-series data of accelerations GA. In step S132, the execution device 61 extracts the time-series data of the target heart sound HB and acceleration GA from the time-series data of the multiple heart sound HB and acceleration GA acquired in step S131. Specifically, the execution device 61 identifies the heart sound sensor 40 that detected the loudest heart sound HB based on information from the multiple heart sound sensors 40. The execution device 61 also extracts information from the heart sound sensor 40 that detected the loudest heart sound HB and information from the acceleration sensor 30 paired with that heart sound sensor 40 as information from the paired sensor located in an appropriate position. This allows information to be extracted from the paired sensor located in the most appropriate position out of the multiple paired sensors included in the detection device 110. If the data is extracted in this manner, it is possible to reduce the amount of work required for the user of the monitoring system MS when extracting the data as described above.

[0088] <Example of change> This embodiment can be modified as follows: This embodiment and the following modifications can be combined and implemented within the scope of technical compatibility.

[0089] In the first embodiment, the configuration of the monitoring system MS may be changed. For example, the configuration of the housing 20 of the detection device 10 may be changed. As a specific example, as shown in FIG. 14 , the appearance of the housing 20 may be a generally rectangular prism shape. Note that, as one example, in the rectangular prism-shaped housing 20, one corner of the housing 20 may have a shape similar to a so-called C-chamfer. With this configuration, for example, a user of the monitoring system MS or the like can easily grasp the orientation of the housing 20. Furthermore, as one example, from the viewpoint of enabling a user of the monitoring system MS or the like to grasp the orientation of the housing 20, the housing 20 may be provided with a mark or the like for grasping the orientation of the housing 20.

[0090] For example, the relative positions of the sensors in the detection device 10 may be changed. As a specific example, as shown in Fig. 14, the distance between any one heart sound sensor 40 and the acceleration sensor 30 may be different from the distance between any other one heart sound sensor 40 and the acceleration sensor 30. More specifically, as shown in Fig. 14, when the detection device 10 is viewed in a direction perpendicular to the main surface of the housing 20, the multiple heart sound sensors 40 may be arranged in a grid pattern surrounding the acceleration sensor 30. In this case, it is preferable that the multiple light emitters 50 are arranged in a grid pattern adjacent to the multiple heart sound sensors 40.

[0091] For example, the configuration of the inertial sensor in the detection device 10 may be changed. As a specific example, the acceleration sensor 30 serving as the inertial sensor may be a so-called triaxial sensor. As a specific example, the detection device 10 may include an angular velocity sensor serving as the inertial sensor instead of the acceleration sensor 30. As a further specific example, the detection device 10 may include the acceleration sensor 30 and an angular velocity sensor as the inertial sensor. In other words, the inertial sensor may be any sensor that detects the movement of the body surface caused by the movement of the subject's heart H.

[0092] For example, the appearance of the detection device 10 and the number of sensors may be modified. As a specific example, as shown in FIG. 17 , the detection device 10 includes a housing 20, one acceleration sensor 30, and one heart sound sensor 40. The housing 20 is generally rectangular. The heart sound sensor 40 is attached to the first outer surface 21A of the housing 20. The acceleration sensor 30 is attached to the second outer surface 22A of the housing 20. When the detection device 10 is viewed in a direction perpendicular to the second outer surface 22A of the housing 20, the position of the acceleration sensor 30 exactly coincides with the position of the heart sound sensor 40. With this configuration, for example, a user of the monitoring system MS can determine the appropriate position of the detection device 10 relative to the subject by moving the detection device 10 relative to the subject based on the magnitude of the heart sound HB detected by the heart sound sensor 40. Furthermore, for example, a user of the monitoring system MS can position the acceleration sensor 30, which serves as an inertial sensor, in an appropriate position by turning the detection device 10 upside down. In the above configuration, when the detection device 10 is viewed in a direction perpendicular to the second outer surface 22A of the housing 20, the acceleration sensor 30 does not have to be positioned over the heart sound sensor 40.

[0093] Furthermore, in the above configuration, for example, the execution device 61 of the control device 60 may execute the following process instead of the position identification control. As a specific example, the execution device 61 accesses the storage device 62 to acquire time-series data of the heart sound HB from the current time until a predetermined period ago. Here, the predetermined period is a period longer than two pulsation cycles of the heart H. Next, based on the acquired time-series data of the heart sound HB, the execution device 61 identifies, for the most recent cycle of multiple pulsation cycles of the heart H, the maximum value of the heart sound HB included in that cycle as the heart sound HB at a first time point. Furthermore, based on the acquired time-series data of the heart sound HB, the execution device 61 identifies, for the cycle one cycle before the most recent cycle of the multiple pulsation cycles of the heart H, the maximum value of the heart sound HB included in that cycle as the heart sound HB at a second time point. Next, the execution device 61 determines whether the heart sound HB at the first time point is louder than the heart sound HB at the second time point. When the execution device 61 determines that the heart sound HB at the first time point is louder than the heart sound HB at the second time point, the execution device 61 causes the notification device to notify the user that the heart sound HB at the first time point is louder than the heart sound HB at the second time point. As an example, the execution device 61 may output a control signal to the display 82 via the calculation device 70, thereby causing the display 82 to notify the user that the heart sound HB at the first time point is louder than the heart sound HB at the second time point. In this case, the display 82 functions as the notification device.

[0094] For example, the external appearance and internal configuration of the detection device 10 may be changed. As a specific example, the acceleration sensor 30 may be attached to the first inner surface 21B of the first wall portion 21. Also, as a specific example, the heart sound sensor 40 may be attached to the first inner surface 21B of the first wall portion 21.

[0095] For example, the configuration of the light emitter 50 of the alarm device may be changed. As a specific example, instead of being attached to the second wall 22 of the housing 20, the light emitter 50 may be attached to a side wall of the housing 20 that connects the first wall 21 and the second wall 22. Even with this configuration, for example, a user of the monitoring system MS may be able to ascertain the position of the heart sound sensor 40 that detected the loudest heart sound HB by visually checking the on / off state of the light emitter 50 adjacent to the heart sound sensor 40.

[0096] For example, the devices constituting the notification device may be changed. As a specific example, as shown in FIG. 15 , the detection device 10 may include a display 55 capable of displaying an image instead of the multiple light emitters 50. In this case, for example, the display 55 may be attached to the second wall 22 of the housing 20. In this case, during the position identification control, the execution device 61 of the control device 60 may execute a process of notifying the position of the heart sound sensor 40 that detected the loudest heart sound HB by switching the image displayed on the display 55 depending on the position of the heart sound sensor 40 that detected the loudest heart sound HB. This allows, for example, when a user of the monitoring system MS holds and moves the detection device 10, the user can check the information on the display 55 while keeping the housing 20 of the detection device 10 in their field of view.

[0097] For example, the configuration of the notification device may be changed. As a specific example, the execution device 61 of the control device 60 may output a control signal to the display 82 via the calculation device 70, thereby causing the display 82 to function as a notification device. In other words, the sensor unit may not include a notification device, but may include only the detection device 10 and the control device 60. Note that, when focusing only on monitoring the movement of the heart H, the monitoring system MS may not include the calculation device 70, input device 81, and display 82.

[0098] For example, the configuration of the information processing device may be changed. As a specific example, the control device 60 and the arithmetic device 70 may function as the information processing device. That is, the information processing device is not limited to the control device 60. Note that, when focusing only on detecting the heart sound HB and the acceleration GA, the sensor unit may not include the control device 60 and may include only the detection device 10.

[0099] In the first embodiment, the location identification control may be changed. For example, the determination process in step S14 may be changed. As a specific example, in step S14, the execution device 61 calculates the average value of the representative values ​​of the multiple heart sounds HB in step S12. Next, the execution device 61 calculates the absolute value of the difference between the largest representative value in step S12 and the average value. The execution device 61 may then determine whether the absolute value of the calculated difference is less than a predetermined fixed difference TA. The fixed difference TA may be adjusted as appropriate.

[0100] For example, the method of controlling the light emitters 50 in step S21 may be changed. As a specific example, in step S21, the execution device 61 may output a control signal to the detection device 10 to turn off all of the light emitters 50. That is, it is sufficient that the method of controlling the light emitters 50 in step S21 is different from the method of controlling the light emitters 50 in step S22. If they are different in this way, the processing of step S21 allows, for example, a user of the monitoring system MS to know that the detection device 10 is placed in an appropriate position.

[0101] For example, the method of controlling the light emitters 50 in step S22 may be changed. As a specific example, in step S22, the execution device 61 may output a control signal to the detection device 10 to cause the light emitter 50 corresponding to the heart sound sensor 40 identified in step S12 to emit light, as well as the light emitters 50 adjacent to that light emitter 50. That is, in step S22, the execution device 61 may cause some of the multiple light emitters 50 to emit light, including the light emitter 50 corresponding to the heart sound sensor 40 that detected the loudest heart sound HB.

[0102] In the first embodiment, the generation control may be changed. For example, the precondition in step S33 may be changed. As a specific example, the execution device 61 may determine that the precondition is met when the time-series data of the heart sound HB includes one or more time periods during which the heart sound HB is equal to or greater than a predetermined reference value TB. In other words, the precondition does not have to be that the heart sound sensor 40 repeatedly detects a heart sound HB equal to or greater than the predetermined reference value TB.

[0103] For example, the determination process of step S33 may be omitted. As a specific example, if time-series data of the heart sound HB and the acceleration GA can be appropriately obtained in a situation where the housing 20 of the detection device 10 is placed in an appropriate position on the subject, the determination process of step S33 may be omitted. In this case, after step S32, the execution device 61 may proceed with the process to step S34.

[0104] In the first embodiment, the calculation control may be changed. For example, the calculation configuration in step S53 may be changed. As a specific example, in step S53, the execution device 61 may calculate the period from the closing timing of the aortic valve H4B to the opening timing of the aortic valve H4B instead of or in addition to the release period PR.

[0105] In the first embodiment, the calculation control may be omitted. For example, if there is little need to calculate the release period PR, the calculation control may be omitted. In this case, the execution unit 61 of the control unit 60 may start the abnormality determination control after finishing the generation control.

[0106] In the first embodiment, the abnormality determination control may be changed. For example, the determination process of step S71 may be omitted. As a specific example, if there is little need to determine whether or not there is an abnormality in the respiratory system of the subject, the determination process of step S71 may be omitted. In this case, for example, the execution device 61 of the control device 60 may execute the process of step S72 when starting abnormality determination control.

[0107] For example, the start condition of the determination process in step S72 may be changed. As a specific example, the execution device 61 may execute the determination process in step S72 regardless of the determination result in step S71.

[0108] For example, the determination process of step S72 may be omitted. As a specific example, if there is little need to determine whether or not there is an abnormality in the aortic valve H4B of the subject, the determination process of step S72 may be omitted. In this case, for example, if the executing device 61 does not determine in step S71 that there is noise equal to or greater than the predetermined value TC over the predetermined period PC (S71: NO), the executing device 61 may proceed with the process to step S73.

[0109] For example, the start condition of the determination process in step S73 may be changed. As a specific example, the execution device 61 may execute the determination process in step S73 regardless of the determination result in step S71. As above, the start condition of the determination process in step S74 may be changed.

[0110] For example, the determination process of step S73 may be omitted. As a specific example, if there is little need to determine whether or not there is an abnormality in the mitral valve H3B of the subject, the determination process of step S73 may be omitted. As above, the determination process of step S74 may be omitted.

[0111] In the first embodiment, the abnormality determination control may be omitted. For example, if there is little need to determine whether or not there is an abnormality in the subject's respiratory system, etc., the abnormality determination control may be omitted.

[0112] In the second embodiment, the configuration of the monitoring system MS may be changed. For example, the configuration of the housing 20 of the detection device 110 may be changed. As a specific example, the exterior of the housing 20 may be roughly a square prism shape, as shown in FIG.

[0113] For example, the positional relationship of the sensors in the detection device 110 may be changed. As a specific example, as shown in FIG. 16, the detection device 110 first includes a total of 10 sensor groups. When the detection device 110 is viewed in a direction perpendicular to the main surface of the housing 20, two of the 10 sensor groups are located near the center of the housing 20. When the detection device 110 is viewed in a direction perpendicular to the main surface of the housing 20, the remaining eight sensor groups, excluding the two sensor groups, may be arranged to surround the two sensor groups. In FIG. 16, the heart sound sensor 40 is indicated by a dot among the acceleration sensor 30 and the heart sound sensor 40.

[0114] The sensor unit of Patent Document 1 includes a housing and an angular velocity sensor. The angular velocity sensor is attached to the housing. The angular velocity sensor is a sensor for detecting body surface movements caused by the movement of the subject's heart.

[0115] When monitoring a subject's heart using the sensor unit of Patent Document 1, for example, a user of the sensor unit places the housing of the sensor unit on the subject's body surface near the heart while the subject is lying on his / her back. In this state, the sensor unit detects the movement of the subject's heart based on the movement of the subject's body surface detected by the angular velocity sensor.

[0116] When monitoring a subject's heart using a sensor unit such as that disclosed in Patent Document 1, the angular velocity sensor of the sensor unit detects various signals corresponding to the movements of various parts of the subject's heart. However, due to the complexity of the signals detected by the angular velocity sensor, it may not be possible to appropriately monitor the movement of the subject's heart solely based on information from the angular velocity sensor of the sensor unit. Note that although an angular velocity sensor has been used as an example here, similar issues arise when monitoring is performed using an inertial sensor that detects the movement of the subject's body surface, not just an angular velocity sensor.

[0117] In view of these issues, it is preferable to adopt one of the configurations [1] to [9] described below. This configuration allows for more detailed monitoring than when relying solely on information from an inertial sensor, for example.

[0118] <Other technical ideas> The technical ideas that can be understood from the above-described embodiment and modified examples will be described. [1] The housing and a heart sound sensor attached to the housing and configured to detect heart sounds generated by the movement of the subject's heart; an inertial sensor attached to the housing and configured to detect a body surface movement caused by the heart movement; an information processing device that monitors the movement of the heart based on information acquired from the heart sound sensor and the inertial sensor; Equipped with Monitoring system.

[0119] [2] The information processing device includes: determining whether the acquired information from the heart sound sensor satisfies a predetermined precondition indicating that the housing is placed in an appropriate position on the subject; a process of performing the monitoring based on information acquired from the heart sound sensor and the inertial sensor, with the determination that the precondition is satisfied as a necessary condition; Run [1] The monitoring system described in [1].

[0120] [3] The precondition is that the heart sound is repeatedly detected by the heart sound sensor at a value equal to or greater than a predetermined reference value. [2] The monitoring system described in [2].

[0121] [4] The information processing device includes: determining an opening timing of an aortic valve in the heart based on information from the inertial sensor; A process for identifying a timing of closure of the aortic valve based on information from the heart sound sensor; A process of calculating a release period, which is a period from the release timing to the close timing, based on the identified release timing and close timing; Run [1] The monitoring system described in [1].

[0122] [5] The information processing device includes: determining an opening timing of an aortic valve in the heart based on information from the inertial sensor; A process of acquiring the heart sound at the release timing based on information from the heart sound sensor; a process of determining whether the heart sound at the release timing is equal to or greater than a predetermined value; a process of determining that there is an abnormality in the aortic valve when it is determined that the heart sound at the release timing is equal to or greater than the specified value; Run [1] The monitoring system described in [1].

[0123] [6] The information processing device includes: determining a timing of mitral valve opening in the heart based on information from the inertial sensor; A process of acquiring the heart sound at the release timing based on information from the heart sound sensor; a process of determining whether the heart sound at the release timing is equal to or greater than a predetermined value; a process of determining that there is an abnormality in the mitral valve when it is determined that the heart sound at the release timing is equal to or greater than the specified value; Run [1] The monitoring system described in [1].

[0124] [7] The information processing device includes: determining whether or not there is a noise level equal to or greater than a predetermined value over a predetermined period of time based on information from the heart sound sensor; a process of determining that there is an abnormality in the respiratory system of the subject when it is determined that there is noise equal to or greater than the predetermined value over the predetermined period of time; Run [1] The monitoring system described in [1].

[0125] [8] The information processing device includes: determining an opening timing of an aortic valve in the heart based on information from the inertial sensor; A process of acquiring the heart sound at the release timing based on information from the heart sound sensor; a process of determining whether the heart sound at the release timing is equal to or greater than a predetermined value; a process of determining that there is an abnormality in the aortic valve when it is determined that there is no noise equal to or greater than the predetermined value over the predetermined period and the heart sound at the release timing is equal to or greater than the specified value; Run The monitoring system described in [7].

[0126] [9] The information processing device includes: determining a timing of mitral valve opening in the heart based on information from the inertial sensor; A process of acquiring the heart sound at the release timing based on information from the heart sound sensor; a process of determining whether the heart sound at the release timing is equal to or greater than a predetermined value; a process of determining that there is an abnormality in the mitral valve when it is determined that there is no noise equal to or greater than the predetermined value over the predetermined period and the heart sound at the release timing is equal to or greater than the specified value; Run The monitoring system described in [7]. [Explanation of symbols]

[0127] MS...Monitoring System 10...Detection device 20…Housing 20A…Center axis line 21…First wall part 21A…1st outer surface 22…Second wall part 22A…Second outer surface 30...Acceleration sensor 40...Heart sound sensor 50...Light emitter 55...Display 60...Control device 61...Execution device 62…Storage device 62A...Information processing program 70...Arithmetic device 71...Execution device 72…Storage device 81...Input device 82...Display 110...Detection device

Claims

1. The housing and a heart sound sensor attached to the housing and configured to detect heart sounds generated by the movement of the subject's heart; an inertial sensor attached to the housing and configured to detect a body surface movement caused by the heart movement; Equipped with Sensor unit.

2. a detection device including the housing, the inertial sensor, and a plurality of the heart sound sensors; a notification device that issues a notification; an information processing device capable of communicating with the detection device and the notification device; Equipped with the plurality of heart sound sensors are arranged to surround the inertial sensor; The information processing device includes: acquiring information from the plurality of heart sound sensors; A process of identifying the heart sound sensor that detected the loudest heart sound based on information from multiple heart sound sensors; a process of notifying the position of the heart sound sensor that detected the loudest heart sound by the notification device; Run The sensor unit according to claim 1 .

3. The notification device includes a plurality of light emitters corresponding to the plurality of heart sound sensors, the light emitter is attached to the housing at a position adjacent to the corresponding heart sound sensor; The information processing device includes: By switching on and off each of the plurality of light emitters in accordance with the position of the heart sound sensor that detected the loudest heart sound, a process of notifying the position of the heart sound sensor that detected the loudest heart sound is performed. The sensor unit according to claim 2 .

4. The information processing device includes: A process is executed to cause some of the light emitters, including the light emitter corresponding to the heart sound sensor that detected the loudest heart sound, to emit light. The sensor unit according to claim 3 .

5. The information processing device includes: A process of identifying the heart sound sensor that detected the quietest heart sound based on information from the plurality of heart sound sensors; a process of determining whether the absolute value of the difference between the loudest heart sound and the quietest heart sound is equal to or greater than a predetermined constant difference; When the absolute value is equal to or greater than the predetermined difference, a process of illuminating some of the light emitters, including the light emitter corresponding to the heart sound sensor that detected the loudest heart sound, among the plurality of light emitters; a process of causing all of the light emitters to emit light when the absolute value is less than the predetermined difference; Run The sensor unit according to claim 4 .

6. The notification device includes a display attached to the housing and capable of displaying an image, The information processing device includes: The image displayed on the display is switched depending on the position of the heart sound sensor that detected the loudest heart sound, thereby notifying the user of the position of the heart sound sensor that detected the loudest heart sound. The sensor unit according to claim 2 .

7. When a set of the heart sound sensor and the inertial sensor adjacent to the heart sound sensor is defined as a set of sensors, the set of sensors includes a plurality of the set of sensors. The sensor unit according to claim 1 .

8. a detection device including the housing and a plurality of the sensor groups; an information processing device capable of communicating with the detection device; Equipped with The information processing device includes: acquiring information from the plurality of heart sound sensors; A process of identifying the heart sound sensor that detected the loudest heart sound based on information from multiple heart sound sensors; extracting information from the heart sound sensor that detected the loudest heart sound and information from the inertial sensor paired with that heart sound sensor as information from the paired sensors arranged at appropriate positions; Run The sensor unit according to claim 7 .

9. the outer surface of the housing includes a first outer surface and a second outer surface facing opposite to the first outer surface; the heart sound sensor is attached to the first outer surface; The inertial sensor is attached to the second outer surface. The sensor unit according to claim 1 .

10. a detection device including the housing, the inertial sensor, and the heart sound sensor; a notification device that issues a notification; an information processing device capable of communicating with the detection device and the notification device; Equipped with The information processing device includes: acquiring information from the heart sound sensor; determining whether the heart sound at a first time point is louder than the heart sound at a second time point that is earlier than the first time point based on information from the heart sound sensor; a process of notifying, by the notification device, that the heart sound at the first time point is louder than the heart sound at the second time point, when the heart sound at the first time point is louder than the heart sound at the second time point; Run The sensor unit according to claim 1 .

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