Heart rate detection device, heart rate detection system, heart rate detection method, and program

Abstract

This system accurately generates heart rate information representing the subject's heart rate from a heart rate signal that includes disturbance components caused by the subject's movement, etc. [Solution] The heart rate detection device comprises: a first binarization unit that generates a binarized heart rate signal by binarizing a heart rate signal representing the heart rate of a subject during a measurement period using predetermined hysteresis characteristics; a first edge period calculation unit that calculates the edge time length, which is the time length, for each of a plurality of edge intervals; and an output unit that outputs heart rate information representing the heart rate of a subject based on the edge time length in each of the plurality of edge intervals that divide the measurement period. The plurality of edge intervals are intervals obtained by dividing the measurement period into first edges of the binarized heart rate signal. The first edge is either the rising or falling edge of the binarized heart rate signal.

Description

Technical Field

[0001] The present invention relates to a heartbeat detection device, a heartbeat detection system, a heartbeat detection method, and a program.

Background Art

[0002] In Society5.0, which is one of the science and technology policies in Japan, by utilizing IoT (Internet of Things) technology, in a society where all things are connected to the Internet, new value creation is realized by analyzing data, aiming to achieve both a comfortable, vibrant, and high-quality life, economic development, and the resolution of social issues. Also, IoT technology has begun to be applied in the field of people. For example, Patent Documents 1 to 4 describe technologies for sensing the biological signals of a subject. In recent years, for the realization of Society5.0, technologies for non-contact heartbeat measurement of a subject without the subject's awareness, which leads to the analysis of human health and emotions, have attracted attention.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0004] Sensors that detect heart rate, whether by contact or non-contact, can be prone to false detections, especially when the subject is moving. This is particularly likely with non-contact heart rate detection. The heart rate signal may contain many disturbance components, making it difficult to accurately generate heart rate information such as heart rate interval data (RRI: RR Interval) from the heart rate signal.

[0005] The present invention aims to provide a heart rate detection device, a heart rate detection system, a heart rate detection method, and a program that can accurately generate heart rate interval data representing the heart rate interval of a subject from a heart rate signal that includes disturbance components caused by the subject's movement or other factors. [Means for solving the problem]

[0006] To solve the above-mentioned problems and achieve the objective, the heart rate detection device according to the present invention comprises a first binarization unit, a first edge period calculation unit, and an output unit. The first binarization unit generates a binarized heart rate signal by binarizing the heart rate signal representing the heart rate of the person being measured during the measurement period using predetermined hysteresis characteristics. The first edge period calculation unit calculates the edge time length, which is the duration of time, for each of the plurality of edge intervals. The output unit outputs heart rate information representing the heart rate of the person being measured based on the edge time length in each of the plurality of edge intervals that divide the measurement period. The plurality of edge intervals are intervals obtained by dividing the measurement period into first edges of the binarized heart rate signal. The first edge is either the rising or falling edge of the binarized heart rate signal. [Effects of the Invention]

[0007] According to the present invention, heart rate interval data representing the heart rate interval of a subject can be accurately generated from a heart rate signal that includes disturbance components caused by the subject's movement, etc. [Brief explanation of the drawing]

[0008] [Figure 1]Figure 1 shows the configuration of the heart rate detection system according to the embodiment. [Figure 2] Figure 2 shows the functional configuration of the heart rate detection device. [Figure 3] Figure 3 shows the functional configuration of the heart rate information generation unit. [Figure 4] Figure 4 is a flowchart showing the processing flow of the heart rate information generation unit. [Figure 5] Figure 5 is a flowchart showing the processing flow following Figure 4. [Figure 6] Figure 6 shows an example of a heart rate signal, a binarized signal, and a binarized heart rate signal. [Figure 7] Figure 7 shows an example of the binarized heart rate signal, the first edge, and the information to be adopted during the measurement period. [Figure 8] Figure 8 shows an example of the accepted information in the measurement interval, the accepted information in the re-detection period, the accepted information after synthesis, reliability information, and approval information. [Figure 9] Figure 9 shows the hardware configuration of the information processing device. [Modes for carrying out the invention]

[0009] The embodiments will be described below with reference to the drawings.

[0010] Figure 1 shows the configuration of the heart rate detection system 10 according to the embodiment. The heart rate detection system 10 detects heart rate information that represents information about the subject's heart rate, such as heart rate interval data (RRI: RR Interval) that represents the interval between the subject's heartbeats.

[0011] The heart rate detection system 10 according to this embodiment includes a sensor device 22, a heart rate detection device 24, and a display device 26.

[0012] The sensor device 22 outputs a sensor signal that includes the components of the person being measured's heart rate. For example, the sensor device 22 detects the components of the person being measured's heart rate without contact with the person being measured and outputs a sensor signal that includes the detected heart rate components.

[0013] For example, the sensor device 22 is a camera. The camera functioning as the sensor device 22 images the subject to be measured and outputs the imaging signal obtained by imaging the subject to be measured as a sensor signal. The camera is optical and generates moving images, for example, at a resolution of 2K or higher and a frame rate of 30 fps or higher. When the subject to be measured moves, the camera may follow the subject to be measured so as to include the subject to be measured within the angle of view, and the imaging direction may be controlled to move. The imaging signal output from the camera includes, for example, a component of the heartbeat in the component of the change in the amount of light in the region where the skin of the subject is exposed.

[0014] Also, for example, the sensor device 22 may be a millimeter-wave radar device. The millimeter-wave radar device functioning as the sensor device 22 emits electromagnetic waves in the millimeter-wave band to the subject to be measured and detects the reflected waves from the subject to be measured. Then, the millimeter-wave radar device outputs a radar output signal including the heartbeat component of the subject to be measured as a sensor signal. For example, the millimeter-wave radar device includes at least one MIMO (Multi Input Multi Output) type millimeter-wave radar that transmits and receives radio waves at a frequency of 24 GHz or higher. Note that the millimeter-wave radar device is not limited to the MIMO method and may include a plurality of millimeter-wave radars of other methods.

[0015] Note that the sensor device 22 is not limited to a device that non-contactedly detects the heartbeat component of the subject to be measured, and may be a device that contactedly detects the heartbeat component of the subject to be measured.

[0016] The heartbeat detection device 24 outputs the heartbeat information of the subject to be measured based on the sensor signal output from the sensor device 22. The heartbeat information is, for example, heartbeat interval data. Note that the heartbeat information may be, instead of or in addition to the heartbeat interval data, for example, a heartbeat data series representing the heart rate and the time of the heartbeat.

[0017] The heartbeat detection device 24 may output the heartbeat information of the subject at each unit time which is a predetermined time interval. When outputting the heartbeat information at each unit time, the heartbeat detection device 24 may output error information indicating that the heartbeat information could not be detected in the unit time when the heartbeat information cannot be detected from the sensor signal.

[0018] The heartbeat detection device 24 is constituted by a computer. The heartbeat detection device 24 may be a server device on a network, or may be a cloud or the like in which a plurality of server devices on the network cooperate to operate. When the heartbeat detection device 24 is a server device or the like on a network, the sensor device 22 is connected to the heartbeat detection device 24 via the network. The computer and the server device function as the heartbeat detection device 24 by executing a program.

[0019] The display device 26 acquires the heartbeat information from the heartbeat detection device 24 and displays it on the monitor. Thereby, the display device 26 can let the measurer or the like recognize the heartbeat information of the subject. Also, the display device 26 acquires the error information from the heartbeat detection device 24 and displays it on the monitor. Thereby, the display device 26 can let the measurer or the like recognize that an error has occurred in the detection of the heartbeat information of the subject. Note that the display device 26 may display the heartbeat information and the error information on an LED (Light Emitting Diode) or the like.

[0020] The heart rate detection system 10 may also include, in place of or in addition to the display device 26, at least one of a printer, an audio output device, a storage device, or a communication device. The printer acquires heart rate information and error information from the heart rate detection device 24 and prints it on paper or the like. The audio output device acquires heart rate information and error information from the heart rate detection device 24 and outputs it as audio. The storage device acquires heart rate information and error information from the heart rate detection device 24 and stores it in a storage medium. The communication device acquires heart rate information and error information from the heart rate detection device 24 and transmits it to other devices via a network. By including a printer, an audio output device, a storage device, or a communication device, such a heart rate detection system 10 can also allow the person taking the measurement to recognize the heart rate information of the person being measured and whether an error has occurred.

[0021] Figure 2 shows the functional configuration of the heart rate detection device 24.

[0022] The heart rate detection device 24 comprises a heart rate signal generation unit 32 and a heart rate information generation unit 34.

[0023] The heart rate signal generation unit 32 acquires sensor signals from the sensor device 22 and generates a heart rate signal representing the heart rate of the person being measured. For example, the heart rate signal generation unit 32 extracts image components of the exposed spatial region of the person's skin from the imaging signal output from the camera and generates a heart rate signal based on the image components of the extracted spatial region. Alternatively, for example, the heart rate signal generation unit 32 generates a detection signal representing the heart rate in the person's body from the radar output signal output from the millimeter-wave radar device and generates a heart rate signal based on the generated detection signal.

[0024] The heart rate signal output from the heart rate signal generation unit 32 is time-series data representing the magnitude of the heartbeat. For example, the heart rate signal generation unit 32 outputs a heart rate signal for a predetermined measurement period. However, the heart rate signal output from the heart rate signal generation unit 32 may include disturbance components caused by, for example, the movement of the person being measured, and disturbance components caused by vibration of the sensor device 22.

[0025] The heart rate information generation unit 34 acquires heart rate signals for the measurement period from the heart rate signal generation unit 32 and generates heart rate information based on the acquired heart rate signals. The heart rate information generation unit 34 then outputs the generated heart rate information to the display device 26.

[0026] Figure 3 shows the functional configuration of the heart rate information generation unit 34.

[0027] The heart rate information generation unit 34 includes an acquisition unit 62, a first binarization unit 64, a first BPF unit 66, a first edge period calculation unit 68, a first selected interval identification unit 70, a re-detection period identification unit 72, a differential moving average unit 74, a second binarization unit 76, a second BPF unit 78, a second edge period calculation unit 80, a second selected interval identification unit 82, a synthesis unit 84, a high-reliability interval identification unit 86, an approval area identification unit 88, an output unit 90, and a parameter setting unit 92.

[0028] The acquisition unit 62 acquires a heart rate signal representing the subject's heart rate during the measurement period from the heart rate signal generation unit 32.

[0029] The first binarization unit 64 acquires a heart rate signal from the acquisition unit 62 that represents the magnitude of the subject's heart rate during the measurement period. The first binarization unit 64 generates a binarized heart rate signal by binarizing the heart rate signal during the measurement period using a predetermined hysteresis characteristic.

[0030] More specifically, the first binarization unit 64 generates a binarized heart rate signal that becomes a first value when the heart rate signal is above a preset upper threshold, and a second value when the heart rate signal is below a preset lower threshold. In this case, the lower threshold is the same as or smaller than the upper threshold. When the lower threshold is smaller than the upper threshold, the binarized heart rate signal is a signal obtained by binarizing the heart rate signal using a level-direction hysteresis characteristic.

[0031] Furthermore, in addition to binarization using level-direction hysteresis characteristics, the first binarization unit 64 also performs binarization of the heart rate signal using time-direction hysteresis characteristics. For example, the first binarization unit 64 performs chatter removal on the heart rate signal along with binarization using level-direction hysteresis characteristics, and outputs a binarized heart rate signal from which pulse components shorter than a preset time width in the heart rate signal have been removed. More specifically, the first binarization unit 64 removes pulse components in the heart rate signal that change from a first value to a second value and then return to the first value before a preset threshold time width has elapsed, or pulse components that change from a second value to a first value and then return to the second value before a threshold time width has elapsed. As a result, the binarized heart rate signal becomes a signal obtained by binarizing the heart rate signal using time-direction hysteresis characteristics.

[0032] In the first binarization unit 64, for example, the upper threshold, lower threshold, and threshold time width are set by the parameter setting unit 92.

[0033] The first BPF unit 66 acquires the binarized heart rate signal during the measurement period from the first binarization unit 64. The first BPF unit 66 performs bandpass filtering to restrict the period of the binarized heart rate signal to a range between a preset upper limit period and a preset lower limit period that is smaller than the upper limit period.

[0034] The upper limit period is set by the parameter setting unit 92. The lower limit period is also set by the parameter setting unit 92. For example, the upper limit period may be the reference period plus a predetermined first margin value. The lower limit period may be the reference period minus a predetermined second margin value. In this case, the parameter setting unit 92 can set the upper and lower limit periods in the first BPF unit 66 by setting the reference period for the first BPF unit 66.

[0035] The first edge period calculation unit 68 acquires a binarized heart rate signal from the first BPF unit 66 during a measurement period in which the period is limited between an upper and lower limit period. The first edge period calculation unit 68 detects the first edge in the binarized heart rate signal. The first edge is either the rising or falling edge of the binarized heart rate signal. Furthermore, the first edge period calculation unit 68 divides the measurement period into segments for each first edge to identify multiple edge segments. Furthermore, the first edge period calculation unit 68 calculates the edge time length for each of the multiple edge segments. Finally, the first edge period calculation unit 68 generates information including the edge time length for each of the multiple edge segments.

[0036] The first selection section identification unit 70 obtains information from the first edge period calculation unit 68, including the edge time length of each of the multiple edge sections during the measurement period.

[0037] The first selection interval identification unit 70 identifies, for each of the multiple edge intervals in the measurement period, whether it is a selection interval where the edge time length is greater than or equal to a predetermined lower limit of heart rate intervals and less than or equal to a predetermined upper limit of heart rate intervals, or a non-selection interval where the edge time length is less than the lower limit of heart rate intervals or greater than the upper limit of heart rate intervals. The upper limit of heart rate intervals represents the upper limit of heart rate intervals assumed to be human heart rates and is set by the parameter setting unit 92. The lower limit of heart rate intervals represents the lower limit of heart rate intervals assumed to be human heart rates and is set by the parameter setting unit 92.

[0038] The first edge period calculation unit 68 then generates information for each of the multiple edge intervals in the measurement period, including the edge time length and adoption information indicating whether it is an adopted interval or an unadopted interval.

[0039] The re-detection period identification unit 72 obtains information from the first edge period calculation unit 68 for each of the multiple edge intervals in the measurement period, including the edge time length and adoption information indicating whether it is an adopted interval or an unadopted interval.

[0040] The re-detection period identification unit 72 identifies a re-detection period for which re-detection processing is to be performed, based on the acquired information. The re-detection period is a portion of the measurement period. More specifically, the re-detection period identification unit 72 identifies the unused interval of the measurement period as the re-detection period. The re-detection period identification unit 72 may also identify multiple discrete periods within the measurement period as the re-detection period.

[0041] The differential moving average unit 74 generates a corrected heart rate signal by repeating the differential processing and moving average processing combination a predetermined number of times on the heart rate signal during the re-detection period. The differential moving average unit 74 may perform the differential processing and moving average processing combination once, or it may perform the differential processing and moving average processing combination two or more times.

[0042] The differential moving average unit 74 may also repeat the differential processing and moving average processing combination a predetermined number of times for the heart rate signal over the entire measurement period. Even when such processing is performed, the differential moving average unit 74 can still repeat the differential processing and moving average processing combination a predetermined number of times for the heart rate signal at least during the re-detection period.

[0043] The second binarization unit 76 acquires the corrected heart rate signal during the re-detection period from the differential moving average unit 74. The second binarization unit 76 generates a corrected binarized heart rate signal by binarizing the corrected heart rate signal during the re-detection period using predetermined hysteresis characteristics. The second binarization unit 76 generates a corrected binarized heart rate signal by binarizing the corrected heart rate signal using the same hysteresis characteristics as the first binarization unit 64. Therefore, the same upper limit threshold, lower limit threshold, and threshold time width as the first binarization unit 64 are set by the parameter setting unit 92 for the second binarization unit 76.

[0044] Furthermore, the second binarization unit 76 may generate a corrected binarized heart rate signal for the entire measurement period if the differential moving average unit 74 repeats the differential processing and moving average processing combination for the entire heart rate signal for the measurement period a predetermined number of times. Also, the second binarization unit 76 may be implemented by a software module, functional block, or circuit common to the first binarization unit 64.

[0045] The second BPF unit 78 acquires the corrected binarized heart rate signal during the re-detection period from the second binarization unit 76. The second BPF unit 78 performs bandpass filtering to restrict the period of the corrected binarized heart rate signal during the re-detection period to within the range of an upper and lower period limit. The second BPF unit 78 performs the same bandpass filtering as the first BPF unit 66 on the corrected binarized heart rate signal during the re-detection period. The same upper and lower period limits as the first BPF unit 66 are set by the parameter setting unit 92 in the second BPF unit 78.

[0046] Furthermore, if the second binarization unit 76 is generating a corrected binarized heart rate signal for the entire measurement period, the second BPF unit 78 may perform bandpass filtering on the corrected binarized heart rate signal for the entire measurement period. Also, the second BPF unit 78 may be implemented by a software module, functional block, or circuit common to the first BPF unit 66.

[0047] The second edge period calculation unit 80 acquires a corrected binarized heart rate signal from the second BPF unit 78 during a redetection period in which the period is limited to between the upper and lower limits of the period. The second edge period calculation unit 80 detects the first edge in the acquired corrected binarized heart rate signal and divides the redetection period for each first edge. The second edge period calculation unit 80 calculates the edge time length for each of the two or more edge intervals into which the redetection period has been divided for each first edge. The second edge period calculation unit 80 then generates information including the edge time length for each of the two or more edge intervals in the redetection period. The second edge period calculation unit 80 may be implemented by a software module, functional block, or circuit common to the first edge period calculation unit 68.

[0048] The second selection interval identification unit 82 obtains information from the second edge interval calculation unit 80, including the edge time length of each of the two or more edge intervals in the re-detection period. For each of the two or more edge intervals in the re-detection period, the second selection interval identification unit 82 identifies whether it is a selection interval where the edge time length is greater than or equal to a predetermined lower limit of heart rate intervals and less than or equal to a predetermined upper limit of heart rate intervals, or whether it is a non-selection interval where the edge time length is less than the lower limit of heart rate intervals or greater than the upper limit of heart rate intervals. The second selection interval identification unit 82 determines whether it is a selection interval or a non-selection interval using the same lower limit and upper limit of heart rate intervals as the first selection interval identification unit 70. The parameter setting unit 92 sets the same lower limit and upper limit of heart rate intervals as the first selection interval identification unit 70.

[0049] The second selection section identification unit 82 then generates information for each of the two or more edge sections in the re-detection period, including the edge time length and selection information indicating whether it is a selection section or a non-selection section. The second selection section identification unit 82 may be implemented by a software module, functional block, or circuit common to the first selection section identification unit 70.

[0050] The synthesis unit 84 obtains information from the first adopted section identification unit 70 for each of the multiple edge sections during the measurement period, including the edge time length and adoption information indicating whether it is an adopted section or an unadopted section. The synthesis unit 84 also obtains information from the second adopted section identification unit 82 for each of the two or more edge sections during the re-detection period, including the edge time length and adoption information indicating whether it is an adopted section or an unadopted section.

[0051] The synthesis unit 84 replaces the portion of the multiple edge intervals in the measurement period identified based on the binarized heart rate signal that corresponds to the re-detection period with two or more edge intervals identified based on the corrected binarized heart rate signal. For example, the synthesis unit 84 adjusts the time position of two or more edge intervals identified based on the corrected binarized heart rate signal and replaces them with a portion of the multiple edge intervals in the measurement period identified based on the binarized heart rate signal.

[0052] The synthesis unit 84 outputs information including the edge time length and adoption information for each of the multiple edge segments in the measurement period after replacement.

[0053] The high-confidence interval identification unit 86 obtains information from the synthesis unit 84, including the edge time length and adoption information, for each of the multiple edge intervals during the measurement period.

[0054] The high-confidence interval identification unit 86 identifies selected intervals as high-confidence intervals from among multiple edge intervals during the measurement period, where the variation of the edge time length in the selected interval relative to the average value is less than or equal to a predetermined value. For example, the high-confidence interval identification unit 86 calculates the average value of the edge time length in the selected interval from among multiple edge intervals during the measurement period, and identifies selected intervals as high-confidence intervals where the difference from the calculated average value is within a predetermined value. The difference from the average value used to determine whether or not to identify an interval as a high-confidence interval is predetermined by the parameter setting unit 92.

[0055] Furthermore, the high-confidence interval identification unit 86 identifies edge intervals that are not high-confidence intervals among multiple edge intervals during the measurement period as low-confidence intervals. For each of the multiple edge intervals during the measurement period, the high-confidence interval identification unit 86 outputs information including the edge time length and reliability information that identifies whether it is a high-confidence interval or a low-confidence interval.

[0056] The approval area identification unit 88 obtains information from the high-confidence interval identification unit 86 for each of the multiple edge intervals during the measurement period, including the edge time length and reliability information that identifies whether it is a high-confidence interval or a low-confidence interval. The approval area identification unit 88 identifies the high-confidence intervals among the multiple edge intervals that do not contain low-confidence intervals as the approved area. The approval area identification unit 88 also identifies the edge intervals among the multiple edge intervals that are not the approved area as the non-approved area.

[0057] The approval area identification unit 88 outputs information for each of the multiple edge intervals in the measurement period, including the edge time length and approval information that identifies whether it is an approved area or a non-approved area.

[0058] The output unit 90 obtains information from the approval area identification unit 88, for each of the multiple edge segments during the measurement period, including the edge time length and approval information that identifies whether it is an approved area or a non-approved area.

[0059] The output unit 90 generates and outputs heart rate information based on the edge time length of the edge interval included in the approval area.

[0060] The parameter setting unit 92 sets parameters for each component prior to acquiring the heart rate signal and outputting heart rate information. For example, the parameter setting unit 92 sets parameters for each component based on information received from the user or an external device.

[0061] For example, the parameter setting unit 92 sets an upper threshold, a lower threshold, and a threshold time width for the first binarization unit 64 and the second binarization unit 76. Also, for example, the parameter setting unit 92 sets an upper period and a lower period for the first BPF unit 66 and the second BPF unit 78. Also, for example, the parameter setting unit 92 sets an upper heart rate interval value and a lower heart rate interval value for the first adopted interval identification unit 70 and the second adopted interval identification unit 82. Also, for example, the parameter setting unit 92 sets the difference from the average value of the edge time length, which is a parameter for determining variability, for the high-confidence interval identification unit 86.

[0062] Figure 4 is a flowchart showing the processing flow of the heart rate information generation unit 34. Figure 5 is a flowchart showing the processing flow following Figure 4.

[0063] Next, the processing flow of the heart rate information generation unit 34 will be explained with reference to the flowcharts in Figures 4 and 5. In explaining the processing flow of the heart rate information generation unit 34, the waveform diagrams in Figures 6, 7, and 8 will also be referred to. Figure 6 shows an example of a heart rate signal, a binarized signal, and a binarized heart rate signal. Figure 7 shows an example of a binarized heart rate signal, the first edge, and the adopted information during the measurement period. Figure 8 shows an example of adopted information during the measurement interval, adopted information during the re-detection period, the adopted information after synthesis, reliability information, and approval information.

[0064] First, in S11, the heart rate information generation unit 34 acquires a heart rate signal that represents the magnitude of the subject's heart rate during the measurement period. For example, the heart rate information generation unit 34 acquires a heart rate signal during the measurement period, as shown in Figure 6(A).

[0065] Next, in S12, the heart rate information generation unit 34 generates a binarized signal that becomes the first value when the heart rate signal exceeds a preset upper threshold, and the second value when the heart rate signal falls below a preset lower threshold. The lower threshold is the same as or smaller than the upper threshold. For example, the heart rate information generation unit 34 generates a binarized signal as shown in Figure 6(B).

[0066] Next, in S13, the heart rate information generation unit 34 performs dechattering on the binarized signal and outputs a binarized heart rate signal from which pulse components with a preset time width or less in the binarized signal have been removed. For example, the heart rate information generation unit 34 generates a binarized heart rate signal as shown in Figure 6(C) and Figure 7(A). Note that the heart rate information generation unit 34 may perform the processes in S12 and S13 in a single step rather than sequentially.

[0067] Next, in S14, the heart rate information generation unit 34 performs bandpass filtering on the binarized heart rate signal during the measurement period, restricting the period to within the range of an upper and lower period limit.

[0068] Next, in S15, the heart rate information generation unit 34 detects the first edge in the binarized heart rate signal during the measurement period. For example, the heart rate information generation unit 34 detects the first edge as shown in Figure 7(B).

[0069] Next, in S16, the heart rate information generation unit 34 identifies the first edge in time as the target edge.

[0070] Next, in S17, the heart rate information generation unit 34 determines whether there is a temporally adjacent first edge to the target edge among the multiple first edges detected from the binarized heart rate signal during the measurement period. If there is a temporally adjacent first edge to the target edge (Yes in S17), the heart rate information generation unit 34 proceeds to S18.

[0071] In S18, the heart rate information generation unit 34 calculates the target edge and the edge time length in the target edge interval from the target edge to the next first edge.

[0072] Next, in S19, the heart rate information generation unit 34 determines whether the edge time length in the target edge interval is within the heart rate range, which is greater than or equal to the lower limit of the heart rate interval and greater than or equal to the upper limit of the heart rate interval. If the edge time length of the target edge interval is within the heart rate range (Yes in S19), the heart rate information generation unit 34 proceeds to S20. If the edge time length of the target edge interval is not within the heart rate range (No in S19), the heart rate information generation unit 34 proceeds to S21.

[0073] In S20, the heart rate information generation unit 34 identifies the target edge section as the selected section. After completing S20, the heart rate information generation unit 34 proceeds to processing in S22.

[0074] In S21, the heart rate information generation unit 34 identifies the target edge section as a section to be rejected. After completing S21, the heart rate information generation unit 34 proceeds to processing in S22.

[0075] In S22, the heart rate information generation unit 34 identifies the next first edge after the target edge as the target edge. After completing the processing in S22, the heart rate information generation unit 34 returns to processing in S17.

[0076] The heart rate information generation unit 34 can generate information for each of the multiple edge intervals in the measurement period, including the edge time length and adoption information indicating whether it is an adopted interval or an unadopted interval, by executing the processes from S17 to S22. For example, by repeatedly executing the processes from S17 to S22, the heart rate information generation unit 34 can generate adoption information for the measurement period, as shown in Figure 7(C).

[0077] The heart rate information generation unit 34, in its determination in S17, proceeds to S23 in Figure 5 if there is no next first edge in time relative to the target edge (No. in S17).

[0078] In S23, the heart rate information generation unit 34 identifies the re-detection period. More specifically, the heart rate information generation unit 34 identifies the unusable interval, the interval adjacent to the unusable interval, and a predetermined number or fewer consecutive usable intervals as the re-detection period within the measurement period. For example, the heart rate information generation unit 34 identifies the re-detection period as shown in Figure 8(A). In the example in Figure 8(A), the heart rate information generation unit 34 identifies the unusable interval, the interval adjacent to the unusable interval, and four or fewer consecutive usable intervals as the re-detection period.

[0079] Next, in S24, the heart rate information generation unit 34 generates a corrected heart rate signal by repeatedly performing a combination of differential processing and moving average processing on the heart rate signal during the re-detection period a predetermined number of times.

[0080] Next, in S25, the heart rate information generation unit 34 generates a corrected binarized signal which becomes a first value when the corrected heart rate signal during the re-detection period exceeds a preset upper threshold, and a second value when the heart rate signal falls below a preset lower threshold.

[0081] Next, in S26, the heart rate information generation unit 34 performs dechattering on the corrected binarized signal during the re-detection period and outputs a corrected binarized heart rate signal from which pulse components with a preset time width or less in the corrected binarized signal have been removed.

[0082] Next, in S27, the heart rate information generation unit 34 performs bandpass filtering on the corrected binarized heart rate signal during the re-detection period, restricting the period to within the range of an upper and lower period limit.

[0083] Next, in S28, the heart rate information generation unit 34 detects the first edge in the corrected binarized heart rate signal during the re-detection period.

[0084] Next, in S29, the heart rate information generation unit 34 identifies the first edge in time among the two or more first edges detected from the corrected binarized heart rate signal during the re-detection period as the target edge.

[0085] Next, in S30, the heart rate information generation unit 34 determines whether there is a temporally adjacent first edge to the target edge among the two or more first edges detected from the corrected binarized heart rate signal during the re-detection period. If there is a temporally adjacent first edge to the target edge (Yes in S30), the heart rate information generation unit 34 proceeds to S31.

[0086] In S31, the heart rate information generation unit 34 calculates the target edge and the edge time length in the target edge interval from the target edge to the next first edge.

[0087] Next, in S32, the heart rate information generation unit 34 determines whether the edge time length in the target edge interval is within the heart rate range, which is greater than or equal to the lower limit of the heart rate interval and greater than or equal to the upper limit of the heart rate interval. If the edge time length of the target edge interval is within the heart rate range (Yes in S32), the heart rate information generation unit 34 proceeds to S33. If the edge time length of the target edge interval is not within the heart rate range (No in S32), the heart rate information generation unit 34 proceeds to S34.

[0088] In S33, the heart rate information generation unit 34 identifies the target edge section as the selected section. After completing S33, the heart rate information generation unit 34 proceeds to processing in S35.

[0089] In S34, the heart rate information generation unit 34 identifies the target edge section as a section to be rejected. After completing S34, the heart rate information generation unit 34 proceeds to processing in S35.

[0090] In S35, the heart rate information generation unit 34 identifies the next first edge after the target edge as the target edge. After completing the process in S35, the heart rate information generation unit 34 returns the process to S30.

[0091] The heart rate information generation unit 34 can generate information for each of the two or more edge intervals in the re-detection period, including the edge time length and adoption information indicating whether it is an adopted interval or an unadopted interval, by executing the processes from S30 to S35. For example, by repeatedly executing the processes from S30 to S35, the heart rate information generation unit 34 can generate adoption information for the re-detection period, as shown in Figure 8(B).

[0092] If, in its determination in S30, the heart rate information generation unit 34 determines that there is no next first edge in time relative to the target edge (No. in S30), it proceeds to S36.

[0093] In S36, the heart rate information generation unit 34 replaces the portion of the multiple edge intervals in the measurement period identified based on the binarized heart rate signal that corresponds to the re-detection period with two or more edge intervals identified based on the corrected binarized heart rate signal. More specifically, the heart rate information generation unit 34 replaces the period of the multiple edge intervals identified by the detection of the first edge in S15 that corresponds to the re-detection period with two or more edge intervals identified by the detection of the first edge in S28. For example, by executing the process in S36, the heart rate information generation unit 34 can generate the combined adoption information shown in Figure 8(C).

[0094] Next, in S37, the heart rate information generation unit 34 identifies, as high-confidence intervals, the selected intervals from among the multiple edge intervals in the measurement period in which the variation of the average value of the edge time length in the selected interval is less than or equal to a predetermined value. The heart rate information generation unit 34 also identifies, as low-confidence intervals, the edge intervals from among the multiple edge intervals in the measurement period in which the selected intervals are not high-confidence intervals. For example, the heart rate information generation unit 34 generates reliability information that identifies whether each of the multiple edge intervals in the measurement period is a high-confidence interval or a low-confidence interval, as shown in Figure 8(D).

[0095] Next, in S38, the heart rate information generation unit 34 identifies the high-confidence intervals, which are the intervals between low-confidence intervals and adjacent high-confidence intervals, as approved regions. The approved region identification unit 88 identifies the edge intervals other than the approved regions as unapproved regions. For example, the heart rate information generation unit 34 generates approval information for each of the multiple edge intervals in the measurement period, as shown in Figure 8(E), indicating whether it is an approved region or an unapproved region.

[0096] Next, in S39, the heart rate information generation unit 34 generates heart rate interval data representing the subject's heart rate interval based on the edge time length of the edge interval included in the approval region.

[0097] Next, in S40, the heart rate information generation unit 34 outputs the generated heart rate interval data as heart rate information. For example, the heart rate information generation unit 34 displays the heart rate information on the display device 26.

[0098] The heart rate detection device 24 described above can accurately generate heart rate interval data representing the heart rate interval of the person being measured, even when the heart rate signal contains disturbance components such as those caused by the movement of the person being measured and disturbance components caused by the vibration of the sensor device 22.

[0099] Figure 9 shows the hardware configuration of the information processing device. The heart rate information generation unit 34 is implemented, for example, by a device with a hardware configuration similar to that of a general information processing device, as shown in Figure 9. The information processing device comprises a CPU (Central Processing Unit) 201, an operating device 202, a main memory 203, an auxiliary memory 204, a communication device 205, and a bus 206. Each part is connected by the bus 206.

[0100] The CPU 201 uses a predetermined area of ​​the main memory 203 as a working area and, in cooperation with various programs pre-stored in the auxiliary memory 204, executes various processes and comprehensively controls the operation of each part that constitutes the heart rate information generation unit 34. In addition, the CPU 201 operates the operating device 202 and the communication device 205, etc., in cooperation with the programs.

[0101] The operating device 202 is an input device such as a touch panel, mouse, or keyboard, which receives information input from the user as an instruction signal and outputs that instruction signal to the CPU 201.

[0102] The main memory 203 is a volatile storage medium such as SDRAM (Synchronous Dynamic Random Access Memory). The main memory 203 functions as a workspace for the CPU 201.

[0103] The auxiliary storage device 204 is a rewritable recording device such as a semiconductor storage medium like flash memory, or a magnetically or optically recordable storage medium. The auxiliary storage device 204 stores the program used for control. The communication device 205 transmits and receives data with other devices.

[0104] The program executed by the heart rate information generation unit 34 is stored on a computer connected to a network such as the Internet and provided by downloading it via the network. Alternatively, the program executed by the heart rate information generation unit 34 may be pre-installed on a portable storage medium or the like and provided in that form.

[0105] The program executed by the heart rate information generation unit 34 has a module configuration that includes an acquisition module, a first binarization module, a first BPF module, a first edge period calculation module, a first selected interval identification module, a re-detection period identification module, a differential moving average module, a second binarization module, a second BPF module, a second edge period calculation module, a second selected interval identification module, a synthesis module, a high-confidence interval identification module, an approval area identification module, an output module, and a parameter setting module. The CPU 201 reads such a program from a storage medium or the like and loads each of the above modules into the main memory 203. Then, by executing such a program, the CPU 201 functions as an acquisition unit 62, a first binarization unit 64, a first BPF unit 66, a first edge period calculation unit 68, a first selected interval identification unit 70, a re-detection period identification unit 72, a differential moving average unit 74, a second binarization unit 76, a second BPF unit 78, a second edge period calculation unit 80, a second selected interval identification unit 82, a synthesis unit 84, a high-reliability interval identification unit 86, an approval area identification unit 88, an output unit 90, and a parameter setting unit 92. Furthermore, some or all of the acquisition unit 62, first binarization unit 64, first BPF unit 66, first edge period calculation unit 68, first adopted interval identification unit 70, re-detection period identification unit 72, differential moving average unit 74, second binarization unit 76, second BPF unit 78, second edge period calculation unit 80, second adopted interval identification unit 82, synthesis unit 84, high-reliability interval identification unit 86, approval area identification unit 88, output unit 90, and parameter setting unit 92 may be configured by hardware.

[0106] Although embodiments of the present invention have been described above, these embodiments are presented as examples only and are not intended to limit the scope of the invention. Various modifications can be made to the embodiments. [Explanation of Symbols]

[0107] 10 Heart rate detection system 22 Sensor device 24 Heart rate detection device 26 Display device 32 Heart rate signal generation unit 34 Heart rate information generation unit 62 Acquisition Department 64 First binarization unit 66 1st BPF Department 68 First Edge Period Calculation Unit 70. First Adoption Section Specific Department 72 Re-detection period specification section 74 Differential moving average section 76 Second binarization unit 78 2nd BPF Section 80 Second Edge Period Calculation Unit 82 Second Adoption Section Specific Section 84 Synthesis section 86 High-confidence interval identification section 88 Approved area identification department 90 Output section 92 Parameter setting section

Claims

1. A first binarization unit generates a binarized heart rate signal by binarizing the heart rate signal representing the subject's heart rate during the measurement period using a predetermined hysteresis characteristic, A first edge period calculation unit calculates the edge time length, which is the time length, for each of the multiple edge intervals, An output unit that outputs heart rate information representing the heart rate of the person being measured, based on the edge time length in each of the multiple edge intervals that divide the measurement period, Equipped with, The aforementioned plurality of edge intervals are intervals obtained by dividing the measurement period into intervals for each first edge of the binarized heart rate signal. The first edge is either the rising or falling edge of the binarized heart rate signal. Heart rate detection device.

2. The first binarization unit is, A binarized signal is generated that becomes a first value when the heart rate signal exceeds a preset upper threshold, and a second value when the heart rate signal falls below a preset lower threshold that is the same as or less than the upper threshold. The output is a binarized heart rate signal from which pulse components with a preset time width or less in the binarized signal have been removed. The heart rate detection device according to claim 1.

3. The system further includes a first bandpass filtering unit that limits the period of the binarized heart rate signal to within the range of an upper and lower period limit, The aforementioned lower period is smaller than the aforementioned upper period. The aforementioned upper and lower cycle limits are set based on a preset value or the average value of the cycles of the binarized heart rate signal during the measurement period. The first edge period calculation unit calculates the edge time length for each of the two or more edge intervals in the binarized heart rate signal whose period is limited to between the upper and lower limits of the period. The heart rate detection device according to claim 2.

4. A first selection interval identification unit identifies whether each of the plurality of edge intervals during the measurement period is an adopted interval in which the edge time length is less than or equal to a predetermined upper limit of heart rate intervals and greater than or equal to a predetermined lower limit of heart rate intervals, or an unadopted interval in which the edge time length is greater than or less than the upper limit of heart rate intervals. To further enhance The heart rate detection device according to claim 1.

5. A re-detection period identification unit identifies the non-selected section, the section adjacent to the non-selected section, and a predetermined number or fewer consecutive selected sections within the measurement period as a re-detection period. A differential moving average processing unit generates a corrected heart rate signal by repeating a set of differential processing and moving average processing a predetermined number of times on the heart rate signal during the re-detection period, A second binarization unit generates a corrected binarized heart rate signal by binarizing the corrected heart rate signal during the re-detection period using the hysteresis characteristics, A second bandpass filtering unit that restricts the period of the corrected binarized heart rate signal to within the range of an upper and lower period limit, A second edge period calculation unit calculates the edge time length for each of two or more edge intervals obtained by dividing the re-detection period for each of the first edges in the corrected binarized heart rate signal, in which the period is limited between the upper limit period and the lower limit period. A second adoption section identification unit identifies whether each of the two or more edge sections that define the re-detection period is an adoption section or an adoption section, Furthermore, The aforementioned upper limit period is the period obtained by adding a pre-set first period to the reference period. The aforementioned lower limit period is the period obtained by subtracting a pre-set second period from the aforementioned reference period. The heart rate detection device according to claim 4.

6. The reference period is a value set based on a preset value or the average value of the period of the binarized heart rate signal during the measurement period. The second edge period calculation unit calculates the edge time length for each of the two or more edge intervals in the corrected binarized heart rate signal, in which the period is limited to between the upper and lower limits of the period. The heart rate detection device according to claim 5.

7. The unit further comprises a synthesis unit that replaces the portion of the plurality of edge segments in the measurement period corresponding to the re-detection period with two or more edge segments identified based on the corrected binarized heart rate signal. The heart rate detection device according to claim 5.

8. The system further includes a high-confidence interval identification unit that identifies, among the plurality of edge intervals during the measurement period, an adopted interval in which the variation with respect to the average value of the edge time length in the adopted interval is less than or equal to a predetermined value, as a high-confidence interval. A heart rate detection device according to any one of claims 4 to 7.

9. The system further includes an approval area identification unit that identifies edge sections that are not high-confidence sections among the plurality of edge sections as low-confidence sections, and identifies high-confidence sections obtained by excluding the high-confidence sections adjacent to the low-confidence sections among the plurality of edge sections as approval areas. The heart rate detection device according to claim 8.

10. The output unit generates and outputs the heart rate information based on the edge time length of the edge interval included in the approval area. The heart rate detection device according to claim 9.

11. A sensor device that outputs a sensor signal containing components of the subject's heart rate, A heart rate signal generation unit generates a heart rate signal representing the heart rate of the person being measured based on the sensor signal output from the sensor device, A first binarization unit generates a binarized heart rate signal by binarizing the heart rate signal during the measurement period using predetermined hysteresis characteristics, A first edge period calculation unit calculates the edge time length, which is the time length, for each of the multiple edge intervals, An output unit that outputs heart rate information representing the heart rate of the person being measured, based on the edge time length in each of the multiple edge intervals that divide the measurement period, Equipped with, The aforementioned plurality of edge intervals are intervals obtained by dividing the measurement period into intervals for each first edge of the binarized heart rate signal. The first edge is either the rising or falling edge of the binarized heart rate signal. A heart rate detection system.

12. The information processing device generates a binarized heart rate signal by binarizing the heart rate signal representing the subject's heart rate during the measurement period using a predetermined hysteresis characteristic. The aforementioned information processing device calculates the edge time length, which is the time length, for each of the multiple edge intervals. The information processing device outputs heart rate information representing the heart rate of the person being measured, based on the edge time length in each of the multiple edge intervals that define the measurement period. The aforementioned plurality of edge intervals are intervals obtained by dividing the measurement period into intervals for each first edge of the binarized heart rate signal. The first edge is either the rising or falling edge of the binarized heart rate signal. Heart rate detection method.

13. A program that makes a computer function as a heart rate detection device, The aforementioned computer, A first binarization unit generates a binarized heart rate signal by binarizing the heart rate signal representing the subject's heart rate during the measurement period using a predetermined hysteresis characteristic, A first edge period calculation unit calculates the edge time length, which is the time length, for each of the multiple edge intervals, An output unit outputs heart rate information representing the heart rate of the person being measured, based on the edge time length in each of the multiple edge intervals that divide the measurement period. and make it work The aforementioned plurality of edge intervals are intervals obtained by dividing the measurement period into intervals for each first edge of the binarized heart rate signal. The first edge is either the rising or falling edge of the binarized heart rate signal. program.

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