JP2008125595A - Biological information detecting device, sleeping environment control system and biological information detecting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a biological information detecting device with the excellent noise-resistant property and high accuracy in detecting biological information while using a non-contact sensor. <P>SOLUTION: The biological information detecting device comprises the non-contact sensor part 10 for obtaining biological signals as electric signals without contact with an object for measurement; a spectrum conversion part 14 for converting the biological signals obtained by the non-contact sensor part 10 as electric signals to frequency spectra; a variable band filter part 19 for changing the band width of a passing frequency band according to the size of dispersion of frequency spectra obtained by the spectrum conversion part 14; and a biological information detecting part 20 for detecting biological information based on the frequency spectra passing the variable band filter part 19. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a biological information detection device that detects biological information such as a heart rate and a respiratory rate, a sleep environment control system including the biological information detection device, and a biological information detection method.

There are two types of methods for detecting biological information such as heart rate and respiration rate: a method using a contact sensor in which a sensor element is brought into contact with a human body and a method using a non-contact sensor in which a sensor element is not brought into contact with a human body. In the case of using a contact-type sensor that brings a sensor element into contact with a human body, it is possible to detect biological information by the method described in Patent Document 1, for example. In the case of using a non-contact type sensor that does not bring a sensor element into contact with the human body, for example, biometric information can be detected by the method described in Patent Document 2.
Japanese Patent Laid-Open No. 9-168521 JP-A-11-19056

  By the way, when detecting a living body information during sleep, if a contact type sensor is used, there is a possibility of adversely affecting sleep due to a sense of incongruity of the contact portion. Therefore, use of a non-contact type sensor is desired.

  However, when a non-contact sensor is used, biometric information may not be detected well and heart rate and respiratory rate may be erroneously detected due to noise other than human body signals, noise due to mattress friction, etc. .

  In view of the above circumstances, an object of the present invention is to provide a biological information detection device that has excellent noise resistance and high detection accuracy of biological information while using a non-contact sensor.

  In order to solve the above problems, the biological information detection apparatus according to claim 1 is configured such that a non-contact sensor unit that acquires a biological signal as an electric signal without contacting a measurement target and the non-contact sensor unit are electrically connected. A spectrum conversion unit that converts a biological signal acquired as a signal into a frequency spectrum, a variable band filter unit that changes a bandwidth of a pass frequency band according to the magnitude of dispersion of the frequency spectrum obtained by the spectrum conversion unit, And a biological information detection unit that detects biological information based on the frequency spectrum that has passed through the variable band filter unit.

  According to a second aspect of the present invention, in the biological information detecting apparatus according to the first aspect, before the frequency spectrum is input to the variable band filter unit, the low-frequency spectrum of the frequency spectrum is obtained by nonlinear interpolation processing. A non-linear interpolation processing unit for emphasis is provided.

  According to a third aspect of the present invention, in the biological information detecting device according to the first aspect of the present invention, the biological information detecting device further includes a stagnation state detection unit that determines whether the measurement target is occupying or not. The spectrum conversion unit, the variable band filter unit, and the biological information detection unit are operated only when the measurement target is in bed.

  According to a fourth aspect of the present invention, in the biological information detecting device according to the third aspect, the frequency spectrum when the measurement target is an absent floor is a noise spectrum, and the frequency spectrum when the measurement target is an existing floor is used. A noise spectrum removing unit that subtracts a frequency spectrum obtained by multiplying the noise spectrum is provided.

  According to a fifth aspect of the present invention, in the biological information detecting device according to any one of the first to fourth aspects, the sleep state of the measurement target is estimated based on the peak of the frequency spectrum and the time variation of the dispersion. A sleep state estimation unit is provided.

  A sixth aspect of the present invention is the biological information detecting device according to the fifth aspect, further comprising a sleep abnormality detecting unit that detects the sleep abnormality when a sleep abnormality occurs in the measurement target. To do.

  The invention according to claim 7 is characterized in that, in the biological information detecting device according to claim 6, when the sleep abnormality detecting unit detects a sleep abnormality, the sleep abnormality notifying unit for notifying the result is provided. And

  The sleep environment control system according to claim 8 includes the biological information detection device according to any one of claims 1 to 7 and an external device, and the external device detects the biological information detection device. It is controlled based on the result.

  The biological information detection method according to claim 9 includes a step of acquiring a biological signal as an electric signal without contacting the measurement target, a step of converting the biological signal acquired as the electric signal into a frequency spectrum, and a frequency spectrum. The method includes a step of changing a bandwidth of a passing frequency band of the frequency spectrum in accordance with a magnitude of dispersion of the frequency spectrum and passing the frequency spectrum, and a step of detecting biological information from the passed frequency spectrum. .

  According to the first aspect of the present invention, when the frequency fluctuation of the frequency spectrum is large and the variance is large, the variable band filter section widens the bandwidth of the pass frequency band, so that biological information can be detected. When the variance is small, the variable band filter unit narrows the bandwidth of the pass frequency band, so that the detection accuracy of biological information can be increased.

  In the invention according to claim 2, it is possible to accurately estimate a spectrum in a low frequency band where biological signals such as heart rate and respiration rate exist without increasing the amount of calculation.

  In invention of Claim 3, the power consumption of a biological information detection apparatus can be suppressed.

  In the invention described in claim 4, the spectrum of noise (noise) can be removed, and the detection performance of biological information is improved by taking into account the influence of the installation environment of the biological information detecting device.

  In invention of Claim 5, it can utilize for control of an external apparatus by estimating a sleep state.

  In the invention according to claim 6, when a sleep abnormality occurs in the measurement target, the health condition of the measurement target can be determined by detecting the sleep abnormality.

  In the invention according to claim 7, when a sleep abnormality is detected in the measurement target, the health condition of the measurement target can be confirmed by notifying the result.

  In invention of Claim 8, comfortable sleep can be provided to a to-be-measured object by providing the biological information detection apparatus of the said Claims 1-7.

  According to the ninth aspect of the present invention, when the frequency fluctuation of the frequency spectrum is large and the variance is large, the bandwidth of the pass frequency band of the variable band filter section is widened, so that biological information can be detected. Further, when the variance is small, the bandwidth of the pass frequency band is narrowed, so that the detection accuracy of biological information can be improved. Moreover, it can process in real time.

  Embodiments according to the present invention will be described below with reference to the drawings.

  FIG. 1 shows a sleep environment control system according to the embodiment. Here, FIG. 1A shows a side view, and FIG. 1B shows a top view.

  The biological information detection device 1 is disposed between the bed body 2 and the mattress 3. Thereby, since the biometric information detection apparatus 1 does not contact the user 4, the user 4 is not uncomfortable. The biological information detection apparatus 1 can be separated from the user 4 by 20 to 40 cm. This corresponds to a typical mattress thickness.

  An instruction input device 6 is provided in the vicinity of the pillow 5. A touch panel monitor can be adopted as the instruction input device 6. When an instruction from the user 4 is input, the instruction input device 6 transmits the information to the controller 7.

  The controller 7 is provided inside the bed body 2. The controller 7 controls the external device according to the instruction from the user 4 and the detection result of the biological information detection device 1 to prepare the environment for the user 4. Examples of the external device include AV devices such as a lighting 31, an air conditioner 32, a television 33, and a content player 34.

  FIG. 2 shows a block diagram of the biological information detection apparatus 1.

  The biological information detection apparatus 1 includes a non-contact sensor unit 10, a gain / filter unit 11, an AD converter unit 12, an in-bed state detection unit 13, a spectrum conversion unit 14, a nonlinear interpolation processing unit 15, Unit 16, noise spectrum estimation unit 17, noise spectrum removal unit 18, variable band filter unit 19, biological information detection unit 20, biological information detection control unit 21, sleep state estimation unit 22, and sleep abnormality The detection unit 23, the sleep abnormality notification unit 24, and the data transfer unit 25 have a basic configuration.

  The non-contact type sensor unit 10 has a non-contact type sensor element unit 101 and a sensor IF unit 102 as a basic configuration.

  The non-contact type sensor element unit 101 is a capacitance type vibration sensor, and measures the amount of charge generated by vibration without contacting the user 4 (see FIG. 1).

  The sensor IF unit 102 converts the amount of charge measured by the non-contact sensor element unit 101 into an analog electric signal.

  The gain filter unit 11 performs filtering processing and amplification processing in a desired band on the analog electric signal converted from the amount of electric charge by the sensor IF unit 102. The desired band is a band in which a biological signal appears. The heart rate is 0.5 to 1.5 Hz, and the respiration rate is 0 to 0.1 Hz.

  The AD converter unit 12 converts the analog electric signal that has been subjected to the filtering process and the amplification process by the gain filter unit 11 into a digital electric signal. Note that the sampling frequency at this time is, for example, 1 kHz.

  The occupancy state detection unit 13 detects the occupancy state of the user 4 based on the digital electric signal converted from the analog electric signal by the AD converter unit 12. When the user 4 is present and a biological signal is input, the biological signal appears in a desired frequency band. However, when the user 4 is absent, the biological signal is not input. A strong component of a biological signal does not appear in the frequency band where appears.

  The spectrum conversion unit 14 converts the digital electric signal converted from the analog electric signal by the AD converter unit 12 into a spectrum (frequency spectrum) on the frequency axis. The spectrum conversion unit 14 includes a buffer, and performs FFT when the buffer becomes FULL.

The nonlinear interpolation processing unit 15 performs nonlinear interpolation processing on the frequency spectrum converted by the spectrum conversion unit 14. Depending on the number of points of the size of the buffer provided in the spectrum conversion unit 14, the frequency interval of the frequency spectrum increases, and it may not be possible to capture fine fluctuations such as the heartbeat frequency. In this case, interpolation processing may be performed on the frequency spectrum in order to emphasize the low frequency spectrum and estimate with high accuracy. Examples of the interpolation processing include linear interpolation processing and nonlinear interpolation processing. From the viewpoint of frequency spectrum estimation accuracy, nonlinear interpolation processing is more preferable. As the nonlinear interpolation process, for example, a Lagrange nonlinear interpolation process may be performed. By using several points in the desired band, the frequency spectrum can be estimated effectively. An example of nonlinear interpolation when three points in the desired band are used is shown in FIG. If the three points on the frequency spectrum of the selected section are (x0, g0), (x1, g1), (x2, g2), the function passing through the three points is
G (x) = a0 (x-x1) (x-x2) + a1 (x-x0) (x-x2) + a2 (x-x0) (x-x1)
It becomes. Since G (xi) = gi, a0, a1, and a2 are
a0 = g0 / {(x0-x1) (x0-x2)}
a1 = g1 / {(x1-x0) (x1-x2)}
a2 = g2 / {(x2-x0) (x2-x1)}
It becomes. From the above, x ′ and g ′ are
x ′ = (x0 + x1) / 2
g ′ = a0 (x′−x1) (x′−x2) + a1 (x′−x0) (x′−x2) + a2 (x′−x0) (x′−x1)
It becomes.

  The normalizing unit 16 normalizes the frequency spectrum for which the nonlinear interpolation processing unit 15 has performed the nonlinear interpolation processing. This is because the detection performance of biological information is prevented from depending on the input magnitude of the frequency spectrum, and in particular, the detection performance of biological information is enhanced in an environment where noise is generated.

  The noise spectrum estimation unit 17 calculates a noise spectrum based on the user 4 presence state determined by the presence state detection unit 13. The noise spectrum can be an average value of the frequency spectrum of the absent floor section. In addition, when detecting biological information using the non-contact type sensor unit 10, a case where irregular vibration is applied to the non-contact type sensor unit 10 and a signal is detected regardless of the presence state of the user 4. There is. In particular, there is a high possibility of detecting a signal when vibration is transmitted to the non-contact sensor unit 10 due to vibration characteristics of the installation environment. Such a signal may be a stationary signal or a non-stationary signal, but the stationary signal is often output regardless of the user's 4 presence state.

  The noise spectrum removing unit 18 subtracts the frequency spectrum normalized by the normalizing unit 16 by multiplying the noise spectrum calculated by the noise spectrum estimating unit 17, that is, the average value of the frequency spectrum of the absent floor section. The frequency spectrum from which noise is cut is calculated. The multiplication factor can be set in advance. When the user 4 is not present, the number is 1 time. When the user 4 is present, the noise increases. Therefore, the value is set to 2 times or 3 times.

  The variable band filter unit 19 changes the bandwidth of the pass frequency band and allows it to pass through the frequency spectrum calculated by the noise spectrum removal unit 18 according to the peak in the frequency band in which the biological signal appears and the magnitude of dispersion. The bandwidth can be determined by setting a threshold in advance. The frequency band in which the biological signal appears is, for example, 0.5 to 1.5 Hz in heart rate. As shown in FIG. 4, when the variance (standard deviation) is small, the variable band filter unit 19 sets the bandwidth of the pass frequency band to the narrow bandwidth w1 and passes only the frequency spectrum of the narrow frequency band (FIG. 4). When the variance (standard deviation) is large, the bandwidth of the pass frequency band is set to a wide bandwidth w2, and the frequency spectrum of the wide frequency band is also passed (see FIG. 4B).

  The biological information detection unit 20 detects biological information by analyzing the frequency spectrum that has passed through the variable band filter unit 19. Note that the biological information detection unit 20 may have a removable memory unit depending on the environment and state of the user 4.

  The biological information detection control unit 21 controls the operation of the biological information detection unit 20 based on the presence state of the user 4 determined by the presence state detection unit 13. For example, in order to reduce power consumption, it is preferable to detect the biological information by operating the biological information detection unit 20 only in the in-zone section where the biological information is required.

  The sleep state estimation unit 22 estimates the sleep state of the user 4 from the biological information detected by the biological information detection unit 20. The heart rate and the respiration rate change from moment to moment, and the sleep state such as whether the sleep is shallow or deep, awake or sleep is estimated using the peak of the frequency spectrum and the temporal change of dispersion. By the processing of the sleep state estimation unit 22, for example, the sleep time, the ratio of light sleep and deep sleep, time distribution such as wake up at night can be known.

  The sleep abnormality detection unit 23 detects sleep abnormality from the biological information detected by the biological information detection unit 20 in view of the sleep state of the user 4 estimated by the sleep state estimation unit 22. Sleep abnormalities can be detected by the magnitude of fluctuations in heart rate and respiratory rate that change from moment to moment. For example, when the heart rate of the user 4 is detected but the breathing is not detected, the user 4 may have an apnea syndrome.

  The sleep abnormality notification unit 24 reports the biological information detected by the biological information detection unit 20 and the sleep state of the user 4 estimated by the sleep state estimation unit 22. The sleep abnormality notification unit 22 notifies the user 4 that a sleep abnormality has occurred when the sleep abnormality detection unit 23 detects the sleep abnormality of the user 4. In addition, since the sleep state estimation part 22 can estimate the user 4's wake-up, the user 4 can be notified when the user 4 wakes up without disturbing the user's 4 sleep.

  The data transfer unit 25 transfers data related to the sleep state of the user 4 estimated by the sleep state estimation unit 22 and the biological information detected by the biological information detection unit 20 to the controller 7 (see FIG. 1). The biological information is, for example, the values of heart rate and respiratory rate, the temporal change state thereof, and the like.

  The controller 7 controls the external device according to the data transferred from the data transfer unit 25 and prepares the environment for the user 4. Examples of the external device include AV devices such as a lighting 31, an air conditioner 32, a television 33, and a content player 34. Specifically, according to the data transferred from the data transfer unit 25, the controller 7 turns off the lighting 31 and the television 33 when the user 4 sleeps, or gradually increases the lighting 31 when the user 4 wakes up. Or by causing the television 33 to output an image or sound that prompts the user 4 to wake up, thereby controlling the sleep environment of the user 4. Further, for example, the television 33 that is an external device is controlled so that the health status of the user 4 is displayed.

  The occupancy state detection unit 13 can operate the spectrum conversion unit 14, the variable band filter unit 19, and the biological information detection unit 20 only when the user 4 is occupying the bed.

  An outline of the flow of processing for the biological information detecting apparatus 1 is shown in the flowchart of FIG.

  Processing is performed by interruption of 1 kHz. This is synchronized with the sampling frequency of the AD converter unit 12.

  Processing is started by interruption of 1 kHz. (S1).

  When the interruption occurs, the digital electric signal converted from the analog electric signal by the AD converter unit 12 is stored in a buffer provided in the spectrum conversion unit 14 (S2). At this time, two buffers are prepared. When one of the buffers is FULL, the digital electric signal is sequentially stored in the other buffer.

  If both buffers are not FULL (S3), the process ends (S8).

  On the other hand, when both buffers are FULL (S3), the subsequent processing is performed (S4 to S8).

  First, the spectrum converter 14 converts the digital electrical signal stored in the buffer into a frequency spectrum (S4).

  Next, the variable band filter unit 19 obtains a peak in a desired frequency band, for example, a band of 0.5 Hz to 1.5 Hz and its dispersion in a desired frequency band. If the dispersion is large, the bandwidth of a wide pass frequency band is obtained. If the variance is small, the bandwidth of the narrow pass frequency band is calculated (S5).

  Thereafter, the variable band filter unit 19 passes and filters the frequency spectrum according to the bandwidth of the pass frequency band calculated in S5 (S6). The frequency spectrum filtered here is a frequency spectrum expressing a biological signal.

  And the biometric information detection part 20 detects biometric information using the frequency spectrum which represented the biometric signal (S7).

  When biometric information is detected, the process ends (S8).

  Therefore, when the frequency fluctuation of the frequency spectrum is large and the variance is large, the variable band filter unit 19 widens the bandwidth of the pass frequency band, so that biological information can be detected. When the variance is small, the variable band filter unit 19 narrows the bandwidth of the pass frequency band, so that the detection accuracy of biological information can be improved. Moreover, it can process in real time.

  In addition, by providing the non-linear interpolation processing unit 15, it is possible to accurately estimate a spectrum in a low frequency band where biological signals such as heart rate and respiration rate exist without increasing the amount of calculation.

  Moreover, if the presence state detection unit 13 operates the spectrum conversion unit 14, the variable band filter unit 19, and the biological information detection unit 20 only when the user 4 is in the presence of the floor, the presence of the biological information detection device 1. Power consumption can be reduced.

  Furthermore, by providing the noise spectrum removing unit 18, the spectrum of noise (noise) can be removed, and the detection performance of the biological information is improved in view of the influence of the installation environment of the biological information detecting device 1.

  Moreover, since sleep state estimation can be performed by providing the sleep state estimation part 22, it can utilize for control of an external apparatus.

  Furthermore, since the sleep abnormality can be detected when the sleep abnormality occurs in the user 4 by providing the sleep abnormality detection unit 23, the health state of the user 4 can be determined.

  Furthermore, by providing the sleep abnormality notification unit 24, when a sleep abnormality is detected in the user 4, the result can be notified, so that the health state of the user 4 can be confirmed.

It is a figure which shows the sleep environment control system which concerns on embodiment. It is a block diagram of the living body information detecting device concerning an embodiment. It is a figure which shows the example of the nonlinear interpolation at the time of using 3 points | pieces of a desired zone | band. It is a figure which shows the process of a variable band filter part. It is a flowchart which shows the outline of the flow of a process about the biometric information detection apparatus which concerns on embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Living body detection apparatus 2 Bed main body 3 Mattress 4 User 5 Pillow 6 Instruction input device 7 Controller 10 Non-contact type sensor part 101 Non-contact type sensor element part 102 Sensor IF part 11 Gain filter part 12 AD converter part 13 Accordion state detection Unit 14 spectrum conversion unit 15 nonlinear interpolation processing unit 16 normalization unit 17 noise spectrum estimation unit 18 noise spectrum removal unit 19 variable band filter unit 20 biological information detection unit 21 biological information detection control unit 22 sleep state estimation unit 23 sleep abnormality detection unit 24 Sleep abnormality notification unit 25 Data transfer unit w1, w2 Bandwidth

Claims (9)

A non-contact sensor unit that acquires a biological signal as an electrical signal without contacting the measurement target;
A spectrum conversion unit that converts a biological signal acquired as an electrical signal by the non-contact sensor unit into a frequency spectrum;
A variable band filter unit that changes the bandwidth of the pass frequency band according to the magnitude of the dispersion of the frequency spectrum obtained by the spectrum conversion unit,
A biological information detection unit that detects biological information based on a frequency spectrum that has passed through the variable band filter unit;
A biological information detection device comprising:   The biological information according to claim 1, further comprising: a nonlinear interpolation processing unit that emphasizes a low-frequency spectrum of the frequency spectrum by nonlinear interpolation processing before the frequency spectrum is input to the variable band filter unit. Detection device. A stagnation state detection unit for determining the presence and absence of the measurement target,
The said occupancy state detection part operates the said spectrum conversion part, the said variable band filter part, and the said biometric information detection part, only when the said to-be-measured object is occupancy. Biological information detection device.   A frequency spectrum when the measurement target is an unoccupied floor is used as a noise spectrum, and a noise spectrum removing unit that subtracts a frequency spectrum obtained by multiplying the frequency spectrum when the measurement target is a floor is provided. The biological information detection device according to claim 3.   The biological information detection apparatus according to claim 1, further comprising a sleep state estimation unit that estimates a sleep state of the measurement target based on a peak of a frequency spectrum and a temporal change in dispersion. .   The biological information detection device according to claim 5, further comprising a sleep abnormality detection unit that detects the sleep abnormality when a sleep abnormality occurs in the measurement target.   The biological information detection device according to claim 6, further comprising a sleep abnormality notification unit that notifies a result of sleep abnormality detected by the sleep abnormality detection unit. The biological information detection apparatus according to any one of claims 1 to 7,
An external device,
With
The sleep environment control system, wherein the external device is controlled based on a detection result of the biological information detection device. Acquiring a biological signal as an electrical signal without contacting the measurement object;
Converting a biological signal acquired as an electrical signal into a frequency spectrum;
Changing the bandwidth of the pass frequency band of the frequency spectrum according to the magnitude of the dispersion of the frequency spectrum, and passing the frequency spectrum;
Detecting biological information from the passed frequency spectrum;
A biological information detection method comprising:

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