State determination method, state determination device, state determination system, and recording medium

Abstract

A state determination method, a state determination device, a state determination system, a state determination program, and a recording medium are provided that determine a state of a living body based on an electric signal based on a detected vibration. The state determination device (2) acquires an electric signal based on a detected vibration, performs rectification processing (step S2), performs envelope detection processing that derives an envelope from the rectified electric signal (step S3), and performs state determination processing that determines a state of a living body based on the derived envelope (step S4). The state determination device (2) that determines a state of a living body outputs a result of the determination (step S5).

Description

Technical Field

[0001] The present invention relates to a state determination method for determining the state of an organism, a state determination apparatus using such a method, a state determination system having such a state determination apparatus, and a recording medium recording a state determination program for implementing such a state determination apparatus. Background Technology

[0002] In facilities such as hospitals, nursing homes, and care facilities, nurses and other responsible personnel conduct rounds to confirm whether patients or residents are in bed or out of bed. To assist in such rounds, for example, the applicant of this application has proposed a biodetection system that is placed on the bed to detect the presence or absence of the person being cared for (see, for example, Patent Document 1).

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2015-154926 Summary of the Invention

[0006] The technical problem solved by the invention

[0007] Patent document 1 proposes an excellent biological detection system, but with the aim of further care and improving the quality of nursing, it requires detecting the state of the person being cared for on the bed.

[0008] The present invention is proposed in view of the following circumstances, and its main objective is to provide a state determination method capable of determining the state of an organism.

[0009] Furthermore, another objective of the present invention is to provide a state determination device that applies the state determination method involved in the present invention.

[0010] Furthermore, another objective of the present invention is to provide a state determination system having the state determination device involved in the present invention.

[0011] Furthermore, another object of the present invention is to provide a recording medium that records a state determination program for implementing the state determination device involved in the present invention.

[0012] Technical means to solve the problem

[0013] To solve the above-mentioned technical problems, the state determination method described in this application includes the following steps: rectifying an electrical signal based on vibrations generated from a living organism; deriving an envelope from the rectified electrical signal; and determining the state of the living organism based on the derived envelope.

[0014] In addition, this application discloses a state determination method, in which the determination of the body position of an organism is taken as the state of the organism.

[0015] Furthermore, this application discloses a state determination method, in which the determination is made by comparing the value shown by the derived envelope with a given reference value to determine the body position of a human being, and the body position of the human being as determined includes at least a lying or sitting position.

[0016] In addition, this application discloses a state determination method, in which the given reference value is a bed-getting reference value for determining a person's bed-getting action and a standing reference value for determining a person's getting-up action after getting into bed, and the bed-getting reference value is set to a value larger than the standing-up reference value.

[0017] Furthermore, this application discloses a state determination method. In the state determination method, regarding the determination, if the value shown by the envelope is lower than the bed-getting determination reference value and the get-up determination reference value for a given period of time, it is determined that the person is not present. After the person is determined to be not present, if the value shown by the envelope is higher than the get-up determination reference value and the bed-getting determination reference value, it is determined that the person has performed the bed-getting action.

[0018] Furthermore, this application discloses a state determination method. In the state determination method, regarding the determination, after determining that a person has performed the action of getting into bed, if the value shown by the envelope is higher than the getting-up determination reference value but lower than the getting-in determination reference value, the person's body position is determined to be supine. After determining that the person is supine, if the value shown by the envelope is lower than the getting-up determination reference value, the person's body position is determined to be sitting.

[0019] Furthermore, this application discloses a state determination method in which the envelope is derived by passing an electrical signal of a given frequency band through it.

[0020] Furthermore, this application discloses a state determination method in which the envelope is derived by means of a moving average of the power signal.

[0021] Furthermore, this application discloses a state determination method, in which an A / D converter is used to convert an electrical signal obtained as a vibration-based analog signal into a digital electrical signal, and the rectification is performed on the electrical signal that has been converted into a digital electrical signal.

[0022] Furthermore, the state determination device described in this application is a state determination device comprising a computer including a control unit and a recording unit, wherein the recording unit records a program for causing the computer to execute a rectification unit, an envelope detection unit, and a determination unit: the rectification unit rectifies an electrical signal based on vibrations generated from a living organism, the envelope detection unit derives an envelope from the rectified electrical signal, and the determination unit determines the state of the living organism based on the derived envelope.

[0023] Furthermore, in the state determination device described in this application, the determination unit determines the body position of the organism as the state of the organism.

[0024] Furthermore, in the state determination device described in this application, the determination unit determines the body position of a person as a living organism by comparing the value shown by the envelope derived by the envelope detection unit with a given reference value, and the body position of the person as the determination result includes at least a lying or sitting position.

[0025] Furthermore, in the state determination device described in this application, the given reference value is a bed-getting determination reference value for determining a person's bed-getting action and a standing determination reference value for determining a person who has already gotten into bed's getting-up action. The bed-getting determination reference value is set to a value larger than the standing determination reference value.

[0026] Furthermore, in the state determination device described in this application, if the state indicated by the envelope is lower than the bed-getting determination reference value and the get-up determination reference value for a given period of time, the determination unit determines that the action of getting into bed has been performed. After determining that the action of getting into bed has been performed, if the state indicated by the envelope is higher than the get-up determination reference value and the bed-getting reference value, the determination unit determines that the action of getting into bed has been performed.

[0027] Furthermore, in the state determination device described in this application, after determining that a person has performed the action of getting into bed, if the value shown by the envelope is higher than the getting-up determination reference value but lower than the getting-in determination reference value, the determination unit determines that the person's position is a supine position. After determining that the person is in a supine position, if the value shown by the envelope is lower than the getting-up determination reference value, the determination unit determines that the person's position is a sitting position.

[0028] Furthermore, in the state determination device described in this application, the envelope detection unit derives the envelope by passing an electrical signal of a given frequency band through it.

[0029] Furthermore, in the state determination device described in this application, the envelope detection unit derives the envelope by averaging the power signal.

[0030] Furthermore, the state determination device described in this application includes an A / D conversion unit that converts an electrical signal acquired as a vibration-based analog signal into a digital electrical signal, and the rectification unit rectifies the electrical signal that has been converted into a digital electrical signal.

[0031] Furthermore, the state determination system described in this application comprises: a vibration detection device having a detection unit for detecting vibration and an output unit for outputting an electrical signal based on the detected vibration; and the state determination device, which determines the state of an organism based on the electrical signal output from the vibration detection device.

[0032] Furthermore, in the state determination system described in this application, the detection section of the vibration detection device is sheet-shaped.

[0033] Furthermore, the state determination procedure described in this application enables a computer that acquires an electrical signal based on detected vibration to determine the state of an organism. The state determination procedure enables the computer to perform the following steps: rectifying the vibration-based electrical signal; deriving the envelope from the rectified electrical signal; and determining the state of the organism based on the derived envelope.

[0034] Furthermore, the recording medium described in this application records a state determination program for enabling a computer to determine the state of an organism based on an electrical signal obtained from detected vibrations. The state determination program enables the computer to perform the following steps: rectifying the vibration-based electrical signal; deriving the envelope from the rectified electrical signal; and determining the state of the organism based on the derived envelope.

[0035] Furthermore, this application discloses a state determination device, wherein, when determining whether the state is higher or lower than the bed-going determination reference value or the get-up determination reference value, the determination reference is that the state continues for a given time or more.

[0036] Furthermore, this application discloses a state determination device, wherein a vibration-based electrical signal is amplified, and the amplification rate is adjusted according to the organism whose state is to be determined or the environment in which the state is to be determined.

[0037] Furthermore, this application discloses a state determination device, wherein the bed-going determination reference value or the standing-up determination reference value changes for a given period according to the state of the organism.

[0038] Furthermore, this application discloses a state determination system, which includes a detection device for detecting body information. The state determination device also uses the body information detected by the detection device to determine the state of the organism.

[0039] Invention Effects

[0040] The present invention relates to a state determination method, a state determination device, a state determination system, and a recording medium recording a state determination procedure, which determines the state of a living organism based on the envelope of an electrical signal detected by vibration. Therefore, the present invention achieves excellent results, for example, in determining the state of living organisms such as those being cared for in a facility. Attached Figure Description

[0041] Figure 1 This is a schematic diagram illustrating a structural example of the state determination system described in this application.

[0042] Figure 2 This is a block diagram illustrating structural examples of various devices included in the state determination system described in this application.

[0043] Figure 3 This is a flowchart illustrating an example of the processing of the state determination device described in this application.

[0044] Figure 4 This is a graph illustrating an example of an electrical signal processed by the state determination device described in this application.

[0045] Figure 5 This is a graph illustrating an example of an electrical signal processed by the state determination device described in this application.

[0046] Figure 6 This is a graph illustrating an example of an electrical signal processed by the state determination device described in this application.

[0047] Figure 7 This is a graph illustrating an example of an electrical signal processed by the state determination device described in this application.

[0048] Figure 8 This is a graph illustrating an example of an electrical signal processed by the state determination device described in this application.

[0049] Figure 9 This is a graph illustrating an example of an electrical signal processed by the state determination device described in this application.

[0050] Figure 10 This is a graph illustrating an example of an electrical signal processed by the state determination device described in this application.

[0051] Figure 11 This is a graph illustrating an example of an electrical signal processed by the state determination device described in this application.

[0052] Figure 12 This is a graph illustrating an example of an electrical signal processed by the state determination device described in this application.

[0053] Figure 13 This is a graph illustrating an example of an electrical signal processed by the state determination device described in this application.

[0054] Figure 14 This is a graph illustrating an example of an electrical signal processed by the state determination device described in this application.

[0055] Figure 15 This is a graph illustrating an example of an electrical signal processed by the state determination device described in this application.

[0056] Figure 16 This is a graph illustrating an example of an electrical signal processed by the state determination device described in this application.

[0057] Figure 17 This is a graph illustrating an example of an electrical signal processed by the state determination device described in this application.

[0058] Figure 18 This is a graph illustrating an example of an electrical signal processed by the state determination device described in this application. Detailed Implementation

[0059] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Furthermore, the following embodiments are merely examples embodying the present invention and do not limit the scope of the invention.

[0060] <State Determination System>

[0061] Figure 1 This is a schematic diagram illustrating a structural example of the status determination system described in this application. The status determination system described in this application is installed in facilities such as hospitals, nursing homes, and nursing facilities. Within the facility, there are rooms such as wards and nursing rooms for patients, residents, and other persons receiving care, and each room is equipped with a bed for the person receiving care. Furthermore, the facility includes waiting areas such as nurse stations where nurses, nursing staff, doctors, and other personnel providing care and nursing services to the persons receiving care are on standby.

[0062] A vibration detection device 1 is installed on the bed used by the person being cared for. The vibration detection device 1 includes a vibration detection unit 10 that uses a sheet-like vibration sensor, and amplifies and outputs an electrical signal based on the detected vibration. The vibration detection unit 10 of the vibration detection device 1 is placed on or under a mattress on the bed used by the person being cared for. A sheet or similar material is placed on top of the mattress and the vibration detection unit 10, as needed. Figure 1The illustration shows a patient sitting up from a supine position on a mat and vibration detection unit 10. In this application, a supine position refers to the patient lying horizontally on the bed, including supine, lateral, or abdominal positions. A sitting position refers to the patient raising their upper body on the bed.

[0063] The vibration detection device 1 is connected to a status determination device 2, and the electrical signal output from the vibration detection device 1 is input to the status determination device 2 via a communication line. Furthermore, various communication devices 3, such as nurse call receivers, monitors at the nurse station, and portable telephones held by external personnel, are used as devices capable of communicating with the status determination device 2. The status determination device 2 and the communication device 3 are connected in a communicable manner via communication networks NW such as wireless LAN (Local Area Network), wired LAN, WAN (Wide Area Network), or dedicated communication lines.

[0064] <Structure of various devices>

[0065] Next, the hardware structure of the various devices included in the state determination system described in this application will be explained. Figure 2 This is a block diagram illustrating structural examples of various devices included in the state determination system described in this application. The state determination system includes various devices such as: a vibration detection device 1, a state determination device 2 connected to the vibration detection device 1, a communication device 3 capable of communicating with the state determination device 2, and a body information detection device 4 capable of connecting to the state determination device 2.

[0066] In addition to the vibration detection unit 10, which uses a sheet-like vibration sensor, the vibration detection device 1 also includes various structures such as an amplitude amplification unit 11 and an output unit 12. The vibration detection unit 10 detects vibrations in living organisms such as those being cared for, converts the detected vibrations into analog electrical signals, and outputs them to the amplitude amplification unit 11. The amplitude amplification unit 11 is a signal amplifier that amplifies the voltage of the electrical signal, increasing the amplitude of the analog electrical signal input from the vibration detection unit 10, and outputting it to the output unit 12. The output unit 12 outputs the amplified analog electrical signal from the amplitude amplification unit 11 to the status determination device 2 via a connecting line.

[0067] The status determination device 2 is a device that uses various computers such as signal processing computers and personal computers, and has various structures such as control unit 20, input unit 21, A / D conversion unit 22, recording unit 23, storage unit 24, operation unit 25, output unit 26, communication unit 27, and auxiliary storage unit 28.

[0068] The control unit 20 is equipped with various circuits such as information processing circuits, timing circuits, and register circuits, and is a processor such as a CPU (Central Processing Unit) that performs processing for various parts within the control device.

[0069] The input unit 21 is an interface device such as various adapters and control circuits that receive analog electrical signals transmitted from the vibration detection device 1 via a connecting line.

[0070] The A / D converter 22 is a converter that converts the analog electrical signal received by the input unit 21 into a digital electrical signal.

[0071] The recording unit 23 is a circuit constructed using non-volatile memory such as hard disks, RAID (Redundant Arrays of Inexpensive Disks), and flash memory, as well as volatile memory such as various types of RAM (Random Access Memory), and records various kinds of information. The recording unit 23 records programs such as the basic program (OS) and application programs that run on the basic program. As application programs, it records various programs such as the state determination program 230 for implementing the state determination device 2. Furthermore, the recording unit 23 records various data such as master data such as various reference values ​​used in the state determination program 230, and actual data of the recorded processing history.

[0072] The storage unit 24 is a circuit constructed using volatile memory, which temporarily stores data generated during the execution of various programs. For convenience, the recording unit 23 and the storage unit 24 are represented as different circuits, but they can also be constructed as a single circuit, and their functions can complement each other.

[0073] The operation unit 25 is an operation device such as a touch panel or button, which receives input for operations on the status determination device 2. Alternatively, when the status determination device 2 is configured using a computer such as a personal computer, an operation device such as a keyboard or mouse can also be used as the operation unit 25.

[0074] The output unit 26 is an output device such as a liquid crystal display or a speaker. Alternatively, the operation unit 25 and the output unit 26 may be configured, for example, as a liquid crystal touch panel that has a thin liquid crystal display and a touch panel stacked on top of each other.

[0075] The communication unit 27 is an interface device such as an antenna, LAN adapter, and control circuit used for wireless or wired communication with the communication device 3 via the communication network NW.

[0076] The auxiliary storage unit 28 is an interface device such as a drive or slot that reads various programs and data from a portable recording medium REC such as a CD-ROM, DVD-ROM, or semiconductor memory that contains various programs and data, including a status determination program 230.

[0077] The computer equipped with the various structures illustrated above, under the control of the control unit 20, reads various programs such as the state determination program 230 recorded in the removable recording medium REC and records them in the recording unit 23. Then, the computer reads the various programs such as the state determination program 230 recorded in the recording unit 23, appropriately stores various information in the storage unit 24, and performs various processes such as rectification processing, envelope detection processing, state determination processing, and determination result output processing, thereby operating as the state determination device 2.

[0078] The communication device 3 includes a communication unit 30 that communicates with the status determination device 2 via a communication network NW, and an output unit 31 that performs various outputs. The outputs based on the output unit 31 refer to light output, image display, sound output, sound generation, vibration, and other processing.

[0079] The body information detection device 4 is a device for detecting the body information of the person being cared for, such as heart rate, respiratory rate, and pulse, and should be used appropriately as needed.

[0080] <Handling of various devices>

[0081] Next, the processing of various devices in the state determination system described in this application will be explained. The vibration detection device 1 detects vibrations related to living organisms such as the person being cared for by the vibration detection unit 10, and converts the detected vibrations into analog electrical signals. Furthermore, the vibration detection device 1 amplifies the voltage of the vibration-based analog electrical signal by the amplitude amplification unit 11, and outputs the amplified analog electrical signal to the state determination device 2 by the output unit 12.

[0082] Figure 3 This is a flowchart illustrating an example of the processing of the state determination device 2 described in this application. The state determination device 2 receives an analog electrical signal input from the vibration detection device 1 via the input unit 21, and performs A / D conversion processing (step S1) to convert the received analog electrical signal into a digital electrical signal via the A / D conversion unit 22. In the A / D conversion processing of step S1, the received analog electrical signal is sampled at a given sampling interval such as 10ms, and converted into a digital electrical signal such as 16 bits.

[0083] In step S1, the digital electrical signal converted by the A / D conversion unit 22 is, for example, 16-bit digital data. The control unit 20 of the state determination device 2 processes the digital electrical signal as digital data by executing various programs such as the state determination program 230, thereby utilizing algorithms that include various processes such as rectification processing, envelope detection processing, state determination processing, and determination result output processing.

[0084] The control unit 20 performs rectification processing on the digital electrical signal after A / D conversion (step S2). The rectification processing in step S2 is to convert the signal into pulsating current through rectification processes such as half-wave rectification and full-wave rectification.

[0085] The control unit 20 performs envelope detection processing (step S3) on the rectified digital signal to derive the envelope from the rectified digital signal. The envelope detection processing in step S3 is a smoothing process for the digital signal that has been converted into a pulsating current. Methods for smoothing via envelope detection processing include any one or a combination of moving average processing, BPF (bandpass filtering), and LPF (low-pass filtering). Moving average processing derives the envelope by averaging the signal values ​​of a set number of samples. BPF processing is a digital filtering process that allows digital signals in a specific frequency band to pass through while blocking digital signals in frequency bands outside the passed band; it is performed using filtering processes such as FIR (finite impulse response) filtering and IIR (infinite impulse response) filtering. LPF processing is a digital filtering process that allows digital signals in frequency bands below a specific frequency to pass through while blocking digital signals in frequency bands outside the passed band; it is performed using filtering processes such as FIR filtering and IIR filtering.

[0086] After envelope detection processing, the control unit 20 performs state determination processing (step S4) based on the derived envelope to determine the state of the organism. Step S4 involves comparing the signal value shown by the envelope derived from the envelope detection processing with various reference values ​​pre-recorded in the recording unit 23 to determine the state of the organism. By comparing the signal value shown by the envelope with various reference values, the presence, position, and other states of the organism (i.e., the person being cared for) are determined. Positions determined as states include lying down, sitting, etc. That is, the states include presence / absence and position. Furthermore, positions include lying down, sitting, etc.

[0087] The control unit 20, which determines the state of the organism, performs a determination result output process (step S5) to output the determination result. The determination result output process in step S5 is the process of sending information representing the determination result from the communication unit 27 to the communication device 3 via the communication network NW.

[0088] The communication device 3 receives information indicating the determination result sent from the status determination device 2 via the communication network NW through the communication unit 30, and outputs the received information indicating the determination result from the output unit 31. The output of the determination result is performed as notification processing of various communication devices 3, such as nurse call receivers held by nurses, monitors equipped at nurse stations, and portable telephones held by external personnel, including light output, image display, sound output, beeping, and vibration. Nurses, nursing staff, doctors, family members, and other relevant personnel who have confirmed the determination result output from the communication device 3 can take appropriate measures based on the status of the person being cared for.

[0089] <Specific Examples of Signal Processing>

[0090] Next, specific examples of signal processing related to the rectification processing, envelope detection processing, and state determination processing performed by the state determination device 2 will be explained. Figure 4 This is a graph showing an example of an electrical signal processed by the state determination device 2 described in this application. Figure 4 This is a graph showing the general outline of how the status determination device 2 determines the status of the person being cared for. Figure 4 Using time as the horizontal axis and the signal value of the amplified digital electrical signal as the vertical axis, the passage of the electrical signal over a 20-second period from a certain moment is shown with a sampling interval of 10ms. Figure 4 In this context, Sv1 represents the signal value after A / D conversion in step S1, and Sv2 represents the signal value after rectification in step S2 and envelope detection in step S3. Furthermore, Figure 4 Th1 is the reference value for getting up, and Th2 is the reference value for getting into bed. The reference values ​​for getting up and getting into bed are recorded as reference values ​​for determining the state based on the changes in the signal values ​​shown on the vertical axis. Figure 4 The horizontal axis represents the periods Pa, Pb, Pc, Pd, and Pe, which correspond to the patient's position and status. Figure 4In this context, period Pa represents the period when the caregiver is not in bed; period Pb represents the period when the caregiver performs the action of getting into bed; period Pc represents the period when the caregiver is in a supine position after getting into bed; period Pd represents the period when the caregiver gets up from the supine position; and period Pe represents the period when the caregiver gets up and sits in a sitting position. Signal value Sv1, within period Pc, detects various vibrations caused by the heartbeat, lung respiration, and body movements of the caregiver in the supine position. Signal value Sv1 varies significantly during periods Pb (getting into bed) and Pd (getting up), and remains stable during period Pe (sitting position). Furthermore, signal value Sv2 also captures approximate changes in periods Pa, Pb, Pc, Pd, and Pe of signal value Sv1. The status determination device 2 determines the status of the person being cared for by comparing the signal value Sv2 with the standing-up determination reference value Th1 and the bed-getting-in determination reference value Th2. Figure 4 In the example shown, if the signal value Sv2 remains lower than the standing-up reference value Th1 after the initial determination that the person being cared for is absent, the person is determined to be absent. If, after the initial determination that the person is absent, the signal value Sv2 becomes higher than both the standing-up reference value Th1 and the bed-getting reference value Th2, then the person is determined to have taken a bed-getting action. If, after the initial determination that the person is bed-getting action, the signal value Sv2 becomes higher than both the standing-up reference value Th1 and the bed-getting reference value Th2, then the person is determined to be in a supine position. If, after the person is determined to be in a supine position, the signal value Sv2 becomes lower than the standing-up reference value Th1, then the person is determined to have entered a sitting position.

[0091] Specific examples of signal processing in each step will be further explained. Figure 5 as well as Figure 6 This is a graph showing an example of an electrical signal processed by the state determination device 2 described in this application. Figure 5 as well as Figure 6 Using time as the horizontal axis and the signal value of the amplified digital electrical signal as the vertical axis, the movement of the electrical signal over a period of 20 seconds from a certain moment is shown with a sampling interval of 10ms. Figure 5 as well as Figure 6 The illustrated graph represents the signal when the patient is in a supine position, equivalent to... Figure 4 The state in P1 during the middle period. Figure 5 The image shows the signal value after the A / D conversion process in step S1. Figure 6 Showing the Figure 5 The signal value is the result of half-wave rectification, which is the rectification process in step S2. Figure 5 as well as Figure 6A comparison shows that, in Figure 5 The negative signal value exists in Figure 6 The value in the middle is "0", indicating that half-wave rectification has been performed. As part of the rectification process in step S2, the state determination device 2 can execute... Figure 5 as well as Figure 6 That kind of half-wave rectification.

[0092] Figure 7 as well as Figure 8 This is a graph showing an example of an electrical signal processed by the state determination device 2 described in this application. Figure 7 as well as Figure 8 Using time as the horizontal axis and the signal value of the amplified digital electrical signal as the vertical axis, the movement of the electrical signal over a period of 20 seconds from a certain moment is shown with a sampling interval of 10ms. Figure 7 as well as Figure 8 The illustrated graph represents the signal when the patient is in a supine position, equivalent to... Figure 4 The state in P1 during the middle period. Figure 7 The image shows the signal value after the A / D conversion process in step S1. Figure 8 Showing the Figure 7 The signal value is the result of full-wave rectification, which is the rectification process in step S2. Figure 7 as well as Figure 8 A comparison shows that, in Figure 7 The signal value that is negative is in Figure 8 If the value of the inverted wave turns positive, it indicates that full-wave rectification has been performed. As part of the rectification process in step S2, the state determination device 2 can execute... Figure 7 as well as Figure 8 That kind of full-wave rectification.

[0093] Figure 9 This is a graph showing an example of an electrical signal processed by the state determination device 2 described in this application. Figure 9 Using time as the horizontal axis and the signal value of the amplified digital electrical signal as the vertical axis, the passage of the electrical signal over a 20-second period from a certain moment is shown with a sampling interval of 10ms. Figure 9 The diagram shows the signal value Sv1 after A / D conversion in step S1, and the signal value Sv2 after rectification in step S2 and envelope detection in step S3. Figure 9The example illustrates that, as part of the envelope detection processing in step S3, the signal value Sv2 is smoothed using a moving average process, which averages the most recent 100 samples. Then, as part of the state determination processing in step S4, the state determination device 2 compares the envelope-detected signal value Sv2 with the standing-up determination reference value Th1, determining whether the signal value Sv2 is higher or lower than the standing-up determination reference value Th1, thereby determining the patient's position. Figure 9 In the example shown, when the signal value Sv2 is higher than the standing judgment benchmark Th1, the patient's position is determined to be supine rather than sitting; when it is lower than the standing judgment benchmark Th1, the patient's position is determined to be sitting. Therefore, in Figure 9 In the example, during period P1, the person being cared for was determined to be in a lying position (not a sitting position), and during period P3, the person being cared for was determined to be sitting up.

[0094] Figure 10 This is a graph showing an example of an electrical signal processed by the state determination device 2 described in this application. Figure 10 Using time as the horizontal axis and the signal value of the amplified digital electrical signal as the vertical axis, the passage of the electrical signal over a 20-second period from a certain moment is shown with a sampling interval of 10ms. Figure 10 The diagram shows the signal value Sv1 after A / D conversion in step S1, and the signal value Sv2 after rectification in step S2 and envelope detection in step S3. Figure 10 The example illustrates the signal value Sv2, which has been smoothed by LPF processing, as part of the envelope detection processing in step S3. Figure 10 In the illustrated LPF processing, digital electrical signals in the frequency band below 0.5 Hz are allowed to pass through, while digital electrical signals in the frequency band above 0.5 Hz are blocked. Even after smoothing through LPF processing, a decrease in the signal value Sv2 is observed as the patient's position changes from supine to sitting. Therefore, by setting an appropriate standing judgment reference value Th1, the patient's condition can be determined.

[0095] Figure 11 This is a graph showing an example of an electrical signal processed by the state determination device 2 described in this application. Figure 11 Using time as the horizontal axis and the signal value of the amplified digital electrical signal as the vertical axis, the passage of the electrical signal over a 20-second period from a certain moment is shown with a sampling interval of 10ms. Figure 11 The diagram shows the signal value Sv1 after A / D conversion in step S1, and the signal value Sv2 after rectification in step S2 and envelope detection in step S3. Figure 11The example illustrates the signal value Sv2, which is smoothed through a combination of moving average processing and LPF processing, as part of the envelope detection processing in step S3. Figure 11 In the illustrated envelope detection process, a moving average of the digital electrical signal passing through the frequency band below 0.5 Hz in the LPF processing is taken based on the most recent 100 samples, thereby deriving the signal value Sv2 as the envelope. Even when the moving average processing and LPF processing are combined, a decrease in the signal value Sv2 is observed as the patient's position changes from supine to sitting. Therefore, by setting an appropriate threshold value Th1 for determining whether the patient is getting up, the patient's condition can be determined.

[0096] Figure 12 This is a graph showing an example of an electrical signal processed by the state determination device 2 described in this application. Figure 12 Using time as the horizontal axis and the signal value of the amplified digital electrical signal as the vertical axis, the passage of the electrical signal over a 20-second period from a certain moment is shown with a sampling interval of 10ms. Figure 12 The diagram shows the signal value Sv1 after A / D conversion in step S1, and the signal value Sv2 after rectification in step S2 and envelope detection in step S3. Figure 12 The example illustrates the signal value Sv2, which has been smoothed by BPF processing, as part of the envelope detection processing in step S3. Figure 12 In the illustrated BPF process, digital electrical signals in the 0.1–0.5 Hz frequency band are allowed to pass through, while digital electrical signals in other frequency bands are blocked. Even after smoothing through BPF processing, a decrease in the signal value Sv2 is observed as the patient changes position from supine to sitting. Therefore, by setting an appropriate standing judgment reference value Th1, the patient's condition can be determined.

[0097] Figure 13 This is a graph showing an example of an electrical signal processed by the state determination device 2 described in this application. Figure 13 Using time as the horizontal axis and the signal value of the amplified digital electrical signal as the vertical axis, the passage of the electrical signal over a 20-second period from a certain moment is shown with a sampling interval of 10ms. Figure 13 The diagram shows the signal value Sv1 after A / D conversion in step S1, and the signal value Sv2 after rectification in step S2 and envelope detection in step S3. Figure 13 The example illustrates the smoothed signal value Sv2, which is part of the envelope detection processing in step S3, through a combination of moving average processing and BPF processing. Figure 13In the illustrated envelope detection process, the digital electrical signal passing through the 0.1–0.5 Hz frequency band during BPF processing is averaged based on the most recent 100 samples, thereby deriving the signal value Sv2 as the envelope. Even when the moving average processing and BPF processing are combined, a decrease in the signal value Sv2 is observed as the patient changes position from supine to sitting. Therefore, by setting an appropriate threshold value Th1 for determining whether the patient is getting up, the patient's condition can be determined.

[0098] As a means of determining the state of the person being cared for, the state determination device 2 described in this application can determine not only the body position on the bed, but also the presence or absence of the person being cared for. An example of signal processing for determining the presence or absence of the person being cared for will be explained. Figure 14 This is a graph showing an example of an electrical signal processed by the state determination device 2 described in this application. Figure 14 Using time as the horizontal axis and the signal value of the amplified digital electrical signal as the vertical axis, the movement of the electrical signal over a period of 20 seconds from a certain moment is shown with a sampling interval of 10ms. Figure 14 In this context, Sv1 represents the signal value after A / D conversion in step S1, and Sv2 represents the signal value after rectification in step S2 and envelope detection in step S3. Figure 14 The example illustrates that, as part of the envelope detection processing in step S3, the signal value Sv2, smoothed by moving average processing, is the average of the most recent 100 samples. Furthermore, Figure 14 In this context, Th2 represents the baseline value for determining whether a child should go to bed. Figure 14 The horizontal axis shows periods P4, P5, and P6, which correspond to the presence or absence of the person being cared for and their position. Figure 14 In the process, period P4 is the period when the person being cared for is not in bed; period P5 is the period when the person being cared for performs the action of getting into bed; and period P6 is the period when the person being cared for is in a supine position in bed. As part of the state determination process in step S4, the state determination device 2 compares the signal value Sv2 after envelope detection processing with the bed-getting determination reference value Th2, determining whether the signal value Sv2 is higher or lower than the bed-getting determination reference value Th2, thereby determining the presence or absence and state of the person being cared for. Figure 14 In the example shown, if the signal value Sv2 remains below the bed-entry criterion Th2 for a given period of time after the initial determination that the caregiver is not present, the caregiver is determined to be absent. Furthermore, if the signal value Sv2 changes from below the bed-entry criterion Th2 to above it and remains stable for a certain period of time, the caregiver is determined to be in bed and in a supine position.

[0099] Figure 15 This is a graph showing an example of an electrical signal processed by the state determination device 2 described in this application. Figure 15 Using time as the horizontal axis and the signal value of the amplified digital electrical signal as the vertical axis, the passage of the electrical signal over a 20-second period from a certain moment is shown with a sampling interval of 10ms. Figure 15 The diagram shows the signal value Sv1 after A / D conversion in step S1, and the signal value Sv2 after rectification in step S2 and envelope detection in step S3. Figure 15 The example illustrates the signal value Sv2, which has been smoothed by LPF processing, as part of the envelope detection processing in step S3. Figure 15 In the illustrated LPF processing, digital electrical signals in the frequency band below 0.5 Hz are allowed to pass through, while digital electrical signals in the frequency band above 0.5 Hz are blocked. Even after smoothing through LPF processing, an increase in the signal value Sv2 is observed as the patient gets into bed and assumes a supine position. Therefore, by setting an appropriate bed-entry judgment reference value Th2, the patient's condition can be determined.

[0100] Figure 16 This is a graph showing an example of an electrical signal processed by the state determination device 2 described in this application. Figure 16 Using time as the horizontal axis and the signal value of the amplified digital electrical signal as the vertical axis, the passage of the electrical signal over a 20-second period from a certain moment is shown with a sampling interval of 10ms. Figure 16 The diagram shows the signal value Sv1 after A / D conversion in step S1, and the signal value Sv2 after rectification in step S2 and envelope detection in step S3. Figure 16 The example illustrates the signal value Sv2, which is smoothed through a combination of moving average processing and LPF processing, as part of the envelope detection processing in step S3. Figure 16 In the illustrated envelope detection process, a moving average of the digital electrical signal passing through the frequency band below 0.5 Hz in the LPF processing is taken based on the most recent 100 samples, thereby deriving the signal value Sv2 as the envelope. As an envelope detection process, even when the moving average processing and LPF processing are combined, an increase in the signal value Sv2 is observed as the patient moves into bed and assumes a supine position. Therefore, by setting an appropriate bed-entry judgment benchmark Th2, the patient's condition can be determined.

[0101] Figure 17 This is a graph showing an example of an electrical signal processed by the state determination device 2 described in this application. Figure 17Using time as the horizontal axis and the signal value of the amplified digital electrical signal as the vertical axis, the passage of the electrical signal over a 20-second period from a certain moment is shown with a sampling interval of 10ms. Figure 17 The diagram shows the signal value Sv1 after A / D conversion in step S1, and the signal value Sv2 after rectification in step S2 and envelope detection in step S3. Figure 17 The example illustrates the signal value Sv2, which has been smoothed by BPF processing, as part of the envelope detection processing in step S3. Figure 17 In the illustrated BPF process, digital electrical signals in the 0.1–0.5 Hz frequency band are allowed to pass through, while digital electrical signals in other frequency bands are blocked. Even after smoothing through the BPF process, an increase in the signal value Sv2 is observed as the patient gets into bed and assumes a supine position. Therefore, by setting an appropriate bed-entry judgment reference value Th2, the patient's condition can be determined.

[0102] Figure 18 This is a graph showing an example of an electrical signal processed by the state determination device 2 described in this application. Figure 18 Using time as the horizontal axis and the signal value of the amplified digital electrical signal as the vertical axis, the passage of the electrical signal over a 20-second period from a certain moment is shown with a sampling interval of 10ms. Figure 18 The diagram shows the signal value Sv1 after A / D conversion in step S1, and the signal value Sv2 after rectification in step S2 and envelope detection in step S3. Figure 18 The example illustrates the smoothed signal value Sv2, which is part of the envelope detection processing in step S3, through a combination of moving average processing and BPF processing. Figure 18 In the illustrated envelope detection process, a moving average of the digital electrical signal passing through the 0.1–0.5 Hz frequency band in the BPF processing is taken based on the most recent 100 samples, thereby deriving the signal value Sv2 as the envelope. Even when the moving average processing and BPF processing are combined, an increase in the signal value Sv2 is observed as the patient moves into bed and assumes a supine position. Therefore, by setting an appropriate bed-entry judgment benchmark Th2, the patient's condition can be determined.

[0103] As described above, the state determination device 2 described in this application can acquire electrical signals based on detected vibrations and determine the presence, position, and other states of an organism based on the envelope of the acquired electrical signals. Therefore, for example, in the case of determining the state of a person being cared for in a facility, the state of the person being cared for can be determined even when the caregiver is not present, and the caregiver can be notified. Thus, it provides excellent results, such as enabling the caregiver to respond quickly in situations where the person being cared for may be in an abnormal state.

[0104] This invention is not limited to the embodiments described above and can be implemented in a wide variety of other ways. Therefore, these embodiments are merely illustrative in all respects and should not be interpreted as limiting. The scope of this invention is set forth in the claims and is not limited in any way by the text of the specification. Furthermore, all modifications and alterations falling within the equivalent scope of the claims are within the scope of this invention.

[0105] For example, in the above embodiments, only the determination criteria for getting up (Th1) and getting into bed (Th2) have been illustrated. However, the present invention is not limited to this, and other determination criteria and determination methods can be appropriately set. For example, in order to determine states such as lying down and sitting up, a determination criterion can be further set to be higher or lower than the determination criteria for getting up (Th1) and getting into bed (Th2) for a certain period of time. Therefore, the determination is performed reliably after a state change, thus reducing false alarms.

[0106] Furthermore, in the above embodiment, it can also be configured such that when the voltage of the vibration-based analog electrical signal is amplified by the amplitude amplification unit 11, the amplification rate is adjusted relative to the magnitude of the vibration, which varies depending on factors such as mattress thickness and individual differences of the person being cared for, so that the output voltage amplitude is constant. That is, the state determination device 2 can adjust the amplification rate according to the organism whose state is to be determined or the environment in which the state is to be determined. As a result, the determination reference values ​​for getting up Th1 and getting into bed Th2 can be set to a single value without changing them for each major cause of variation. Thus, the determination reference values ​​do not need to vary depending on factors such as the environment where the sensor is installed or individual differences of the person being cared for.

[0107] Furthermore, for example, in the above embodiment, the reference value Th1 for determining getting up and the reference value Th2 for determining getting into bed are exemplified as unchanging reference values. However, the present invention is not limited to this, and the given period can be changed according to the activity of the person being cared for. As an example, after the signal value Sv1, which has undergone A / D conversion processing in step S1, is higher than a certain reference value, the reference value Th1 for determining getting up is increased for a given period. In cases of significant activity, such as when the person being cared for moves from a supine position to get out of bed, or when there is significant activity based on body movement, the signal value Sv1 increases, and consequently, the signal value Sv2 also increases. Therefore, it may take time for the signal value Sv2 to decrease after getting up, and the determination of getting up may be delayed. In cases of such significant activity, when the signal value Sv1 exceeds a certain reference value, the reference value Th1 for determining getting up is changed significantly for a certain period of time, thereby enabling the determination of getting up to be made earlier in time compared to the existing method of getting up without change.

[0108] Furthermore, for example, the above embodiments only illustrate acquiring electrical signals based on detected vibrations and determining the presence or absence of an organism, its position, and other states based on the envelope of the acquired electrical signals; however, the present invention is not limited to this. Body information detected by the body information detection device 4, which detects bodily information such as heart rate, respiratory rate, and pulse, can also be used in the state determination. As an example, in addition to determining whether to go to bed based on the envelope detected by the vibration detection device 1, the determination of whether to go to bed is also performed after detecting the heart rate. Therefore, the bed-going state can be determined with higher accuracy.

[0109] Furthermore, for example, all the values ​​shown in the above embodiments are merely examples, and the values ​​such as sampling interval, number of samples in moving average, LPF, frequency band in BPF, and various reference values ​​can be appropriately set according to the implementation method.

[0110] Furthermore, for example, the above embodiments illustrate situations such as rising from a lying position to a sitting position and changing from an unoccupied state to a lying position, but the present invention is not limited to these. That is, the state determination device 2 described in this application can detect changes in state corresponding to various situations such as changing from a sitting position to a lying position and changing from a sitting position to an unoccupied state by appropriately setting the state recording and appropriate reference values.

[0111] Furthermore, for example, in the above embodiment, a method is shown in which the vibration detection unit 10 of the vibration detection device 1 is placed on a bed to determine the state of the person being cared for, but the present invention is not limited to this. For example, it can be expanded to determine the state of a driver sitting in the driver's seat of a vehicle, prevent abnormalities such as drowsy driving, etc. In addition, in the present invention, the organism whose state is to be determined is not limited to humans, but can also be applied to animals such as dogs and cats, and can be expanded to various other methods.

[0112] Furthermore, for example, in the above embodiment, the vibration detection device 1 is shown to have an amplitude amplification unit 11 and the state determination device 2 is shown to have an A / D conversion unit 22. However, the present invention is not limited to this, and the structure of each device can be appropriately designed. That is, the vibration detection device 1 may be configured to output a digital electrical signal after performing A / D conversion processing, and the state determination device 2 may be configured to amplify the analog electrical signal. Furthermore, it may be appropriately designed that the output unit 26 of the state determination device 2 performs notification processing for outputting information indicating the determination result, etc., instead of the output unit 31 of the communication device 3.

[0113] Furthermore, in the above embodiment, the rectification process in step S2 and the envelope detection process in step S3 are shown as algorithmic processing for digital electrical signals. However, the present invention is not limited to this and can also be implemented as processing performed on analog circuits for analog electrical signals. That is, the state determination device 2 described in this application can combine electronic components such as diodes, resistors, and capacitors to implement these processes. In this case, the A / D conversion process in step S1 can be omitted.

[0114] However, when analog circuits are constructed by combining electronic components such as diodes, resistors, and capacitors for rectification and envelope detection, technical problems arise that are not particularly problematic in algorithm processing. For example, in analog circuits, it is sometimes difficult to process electrical signals below the forward voltage of the diodes undergoing rectification. Furthermore, the accuracy of rectification and envelope detection processing for minute voltage changes detected by the vibration detection unit 10 becomes a technical problem. While envelope detection processes such as BPF and LPF processing can be performed using analog circuits with operational amplifiers and other motor components, as well as electronic components such as resistors, diodes, and capacitors, there are technical challenges in improving filter characteristics. Furthermore, in analog circuits, it is sometimes difficult to perform moving average processing as envelope detection processing. Therefore, in the state determination system described in this application, a superior system can be constructed by using components, circuits, and devices for processing digital electrical signals.

[0115] Furthermore, while the above embodiments illustrate a method for determining the state of the person being cared for in real time, the present invention is not limited thereto. That is, the state determination system described in this application can be configured to pre-record data based on detected vibrations, and subsequently determine changes in the state of the person being cared for and analyze actions based on the recorded data, and can be developed in various ways.

[0116] Symbol Explanation

[0117] 1 Vibration detection device

[0118] 10 Vibration Testing Department

[0119] 11 Amplification section

[0120] 12 Output Section

[0121] 2. Status determination device

[0122] 20 Control Department

[0123] 21 Input Section

[0124] 22 A / D Conversion Section

[0125] 23 Records Department

[0126] 230 Status Determination Program

[0127] 24 Storage Department

[0128] 25 Operations Department

[0129] 26 Output Section

[0130] 27 Ministry of Communications

[0131] 3 communication device

[0132] 30 Ministry of Communications

[0133] 31 Output Section

[0134] 4. Body Information Detection Device

[0135] NW Communications Network

[0136] REC recording medium.

Claims

1. A state determination method, comprising the following steps: Rectify electrical signals based on vibrations generated from living organisms; Derive the envelope from the rectified electrical signal; and The state of an organism is determined based on the derived envelope. The determination is made by comparing the value shown by the derived envelope with a given reference value to determine the body position of a human being as a living organism. The person's position used to determine the outcome must include at least a lying or sitting position. The given reference values ​​are the reference values ​​for determining a person's action of getting into bed and the reference values ​​for determining a person's action of getting out of bed. The reference value for determining getting into bed is set to a value larger than the reference value for determining getting out of bed. If the value shown by the envelope is lower than both the bed-getting and bed-getting reference values ​​for a given period of time, it is determined that the action of getting into bed has not occurred. After the determination of not occurring, if the value shown by the envelope is higher than both the bed-getting and bed-getting reference values, it is determined that the action of getting into bed has occurred. After determining that a person has taken the action of getting into bed, if the value shown by the envelope is higher than the getting-up determination reference value but lower than the getting-in determination reference value, the person's position is determined to be supine. After determining that the person is supine, if the value shown by the envelope is lower than the getting-up determination reference value, the person's position is determined to be sitting.

2. A state determination device, comprising a computer including a control unit and a recording unit, wherein, The recording unit contains programs for causing the computer to execute the rectification unit, the envelope detection unit, and the determination unit. The rectifier unit rectifies electrical signals based on vibrations generated from the organism. The envelope detection unit derives the envelope from the rectified electrical signal. The determination unit determines the state of the organism based on the derived envelope. The determination method uses a comparison between the value of the envelope derived by the envelope detection method and a given reference value to determine the body position of a human being. The person whose position is being used to determine the outcome must be either in a lying or sitting position. The given reference values ​​are the reference values ​​for determining a person's action of getting into bed and the reference values ​​for determining a person's action of getting out of bed. The reference value for determining getting into bed is set to a value larger than the reference value for determining getting out of bed. If the value shown by the envelope is lower than both the bed-getting determination reference value and the get-up determination reference value for a given period of time, the determination unit determines that the action of getting into bed has occurred. After determining that the action of getting into bed has occurred, if the value shown by the envelope is higher than both the get-up determination reference value and the bed-getting determination reference value, the determination unit determines that the action of getting into bed has occurred. After determining that a person has taken the action of getting into bed, if the value shown by the envelope is higher than the getting-up determination reference value but lower than the getting-in determination reference value, the determination unit determines that the person's position is supine. After determining that the person is supine, if the value shown by the envelope is lower than the getting-up determination reference value, the determination unit determines that the person's position is sitting.

3. The state determination device according to claim 2, wherein, The envelope detection unit derives the envelope by passing an electrical signal of a given frequency band through it.

4. The state determination device according to claim 2, wherein, The envelope detection unit derives the envelope by taking the moving average of the electrical signal.

5. The state determination device according to claim 2, wherein, The state determination device includes an A / D converter that converts the electrical signal acquired as a vibration-based analog signal into a digital electrical signal. The rectifier unit rectifies the electrical signal that has been converted into a digital electrical signal.

6. A state determination system, comprising: A vibration detection device comprising a detection unit for detecting vibration and an output unit for outputting an electrical signal based on the detected vibration; and The state determination device according to any one of claims 2 to 5, The state determination device includes an input section that receives an electrical signal output from the vibration detection device. The state determination device determines the state of the organism based on the electrical signal received by the input unit.

7. The state determination system according to claim 6, wherein, The detection section of the vibration detection device is sheet-shaped.

8. A recording medium recording a state determination program for enabling a computer to determine the state of an organism based on detected electrical signals of vibration, wherein, The recording medium contains a status determination program that causes the computer to perform the following steps: The steps for rectifying vibration-based electrical signals; The steps to derive the envelope from the rectified electrical signal; as well as The steps for determining the state of an organism based on the derived envelope. In the step of determining the state of an organism, the body position of a person is determined by comparing the value shown by the envelope derived in the step of deriving the envelope with a given reference value. The person whose position is being used to determine the outcome must be either in a lying or sitting position. The given reference values ​​are the reference values ​​for determining a person's action of getting into bed and the reference values ​​for determining a person's action of getting out of bed. The reference value for determining getting into bed is set to a value larger than the reference value for determining getting out of bed. If the value shown by the envelope is lower than both the bed-getting and bed-getting reference values ​​for a given period of time, it is determined that the action of getting into bed has not occurred. After the determination of not occurring, if the value shown by the envelope is higher than both the bed-getting and bed-getting reference values, it is determined that the action of getting into bed has occurred. After determining that a person has taken the action of getting into bed, if the value shown by the envelope is higher than the getting-up determination reference value but lower than the getting-in determination reference value, the person's position is determined to be supine. After determining that the person is supine, if the value shown by the envelope is lower than the getting-up determination reference value, the person's position is determined to be sitting.

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