JP2012165979A - Physical information measurement apparatus and physical information measurement program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a physical information measurement apparatus and a physical information measurement program, suppressing influence of a body motion and detecting a biosignal weaker than a body motion signal, even if there is the body motion in time of the detection.SOLUTION: This physical information measurement apparatus 1 detects prescribed physical information from an input signal which includes the detection target biosignal having periodicity and where a plurality of biosignals having different strength are mixed. The physical information measurement apparatus 1 includes: an amplitude compression part 12 performing compression processing of only an amplitude of each wave of the input signal having the strength exceeding a threshold value determined according to the detection target biosignal, and bringing the amplitude of the wave having the strength within the threshold value into a state as it is; and a signal analysis part 13 analyzing an output signal from the amplitude compression part 12, and outputting the prescribed physical information.

Description

  The present invention relates to a physical information measuring device and a physical information measuring program.

  2. Description of the Related Art Conventionally, a body information measuring apparatus that measures body information such as heart rate and respiration rate of a subject such as a human or an animal is known. As a technique related to such a body information measuring device, for example, microwaves as electromagnetic waves are irradiated from a microwave transmission / reception sensor built in the bed toward the chest of the subject lying on the bed, and reflected electromagnetic waves, that is, reflected from the subject. Based on the microwave, what detects a physical state such as a heart rate and a respiration rate of a subject has been proposed (see, for example, Patent Document 1).

  In this case, a signal in the frequency band of the respiration rate is extracted from the reflected electromagnetic wave, which is an output waveform, using a bandpass filter of 0.015 [Hz] to 0.5 [Hz], and 0.5 [Hz] to The heart rate and respiration rate are calculated by extracting a signal in the frequency band of the heart rate using a band pass filter of 3.0 [Hz]. That is, the body movement of the subject lying down by the bed, so-called body movement, is reduced and the body state is measured with high accuracy, and the microwave transmission / reception sensor allows the subject to contact the body without touching or closely contacting the so-called contact sensor. A technique for simply measuring the state is described.

  And when calculating heart rate and respiration rate, for example, FFT (Fast Fourier Transform) frequency analysis is performed, regularity (constant frequency) of each signal is detected, and a plurality of input signals are mixed, The frequency of the target signal corresponding to the heart rate and respiration rate is detected.

JP 2000-102515 A

  However, in the measurement by the so-called Doppler type microwave radar, such as the microwave transmission / reception sensor that detects the reflected wave of the microwave as in the conventional body information measuring device, the influence of the body movement of the subject becomes large. .

  That is, the frequency band of the body motion signal is approximately 0 to 0 although the amplitude of the body motion signal such as movement of the limbs, body movement, and rolling is approximately 10 times that of the respiratory signal and 1000 times that of the heartbeat signal. There is a problem that it is in the range of 10 Hz and overlaps with the frequency regions of respiration and heartbeat, and it becomes difficult to separate and extract the target signal from the body motion signal by frequency.

  The present invention has been made in view of the above circumstances, and is capable of detecting a biological signal weaker than a body motion signal while suppressing the influence of the body motion even when there is a body motion at the time of detection. An object of the present invention is to provide a measuring device and a physical information measuring program.

The present invention employs the following means in order to solve the above problems.
The physical information measuring device according to the present invention is a physical information measuring device that detects predetermined physical information from an input signal including a plurality of biological signals having different intensities including a detection target biological signal having periodicity, An amplitude compression unit that compresses only the amplitude of each wave of the input signal having an intensity exceeding a threshold determined according to the target biological signal, while leaving the amplitude of the wave of the intensity within the threshold as it is, And a signal analysis unit that analyzes an output signal from the amplitude compression unit and outputs predetermined body information.

  In this invention, since all the amplitudes of the signals separated for each frequency band of the input signal are within the threshold value determined in accordance with the detection target biological signal, biological signals having a higher intensity than the detection target biological signal are mixed. However, the level can be set to the same level as that of the detection target biological signal, and the detection target biological signal can be suitably analyzed by the signal analysis unit.

  Further, the physical information measuring device according to the present invention is the physical information measuring device, wherein the compression processing of the amplitude compression unit sets the threshold to the maximum value of the wave peak waveform or the minimum value of the wave valley waveform. The waveform is reduced by multiplying the crest waveform or the trough waveform by the coefficient divided by.

  In the present invention, compression processing is performed not only where the peak value exceeds the threshold value but also the portion from 0 to the threshold value for the peak waveform or valley waveform whose peak value exceeds the threshold value. It can be carried out.

  The physical information measuring device according to the present invention is the physical information measuring device, further comprising a frequency selection unit that reduces signal intensity other than the main band of the detection target biological signal.

  According to the present invention, the detection target biological signal can be separated from noise or the like and analyzed more clearly.

  The physical information measuring device according to the present invention is the physical information measuring device, wherein a first determination unit that determines whether the intensity of the input signal has increased at a first predetermined speed or more, and the first When the determination unit determines that the condition is satisfied, a second determination unit that determines whether or not the intensity of the input signal continues for a first predetermined time or more and a first predetermined time or more, and the second determination unit includes When it is determined that the condition is satisfied, the measurement exclusion processing unit that interrupts the signal processing in the signal analysis unit for this duration, the intensity of the input signal decreases at a second predetermined speed or more, and the second predetermined A measurement restart processing unit that cancels the interruption processing by the measurement exclusion processing unit when the intensity is continued below the intensity and for the second predetermined time or more.

  The present invention can further improve the analysis reliability of the detection target biological signal as a whole by excluding the time zone in which the intensity of the input signal is too large to sufficiently analyze the detection target biological signal. .

  The physical information measuring device according to the present invention is the physical information measuring device, wherein the plurality of biological signals are determined to be out of bed when the intensity of the plurality of biological signals continues for a third predetermined intensity or less and for a third predetermined time or more. When the third determination unit determines that the condition has been satisfied, the measurement exclusion processing unit interrupts the signal processing for the bed leaving duration in the signal analysis unit and no longer satisfies the condition. When the determination is made, the measurement restart processing unit cancels the interruption process in the measurement exclusion processing unit.

  Since the present invention should not be a biological signal to be acquired but should be only noise when leaving the bed, the chance of erroneously determining noise as a biological signal can be reduced, and the analysis reliability of the detection target biological signal as a whole can be further improved. .

  The physical information measurement program according to the present invention causes a computer to function as the physical information measurement device according to the present invention.

  According to the present invention, when analyzing an input signal in which a plurality of biological signals whose frequency components are approximated are mixed even though there is a difference in strength, the relative strengths are not buried in the biological signal having a relatively strong strength. Weak biological signals can be detected.

It is a functional block diagram showing a physical information measuring device concerning a 1st embodiment of the present invention. It is a flowchart which shows the measuring method by the body information measuring apparatus which concerns on the 1st Embodiment of this invention. It is a graph which shows (a) amplitude compression method by the body information measuring device concerning a 1st embodiment of the present invention, and (b) the difference of the signal analysis result by the presence or absence of amplitude compression. It is a graph which shows (a) amplitude compression method by the body information measuring device concerning a 1st embodiment of the present invention, and (b) the difference of the signal analysis result by the presence or absence of amplitude compression. It is a functional block diagram which shows the body information measuring device which concerns on the 2nd Embodiment of this invention. It is a flowchart which shows the measuring method by the body information measuring apparatus which concerns on the 2nd Embodiment of this invention. It is a graph which shows (a) power intensity of an input signal by a physical information measuring device concerning a 2nd embodiment of the present invention, and (b) each existence of existence of exclusion of a body movement continuation period, and an electrocardiogram. It is a functional block diagram which shows the body information measuring device which concerns on the 3rd Embodiment of this invention. It is a flowchart which shows the measuring method by the body information measuring apparatus which concerns on the 3rd Embodiment of this invention. It is a graph which shows each difference with the presence or absence of the exclusion of the (a) input signal by the physical information measuring device which concerns on the 3rd Embodiment of this invention, and the body movement continuation period and the bed leaving period, and an electrocardiogram. is there.

(First embodiment)
A first embodiment according to the present invention will be described with reference to FIGS.
As shown in FIG. 1, the physical information measuring apparatus 1 according to the present embodiment includes a first microwave transmitting / receiving unit 2 and a second microwave transmitting / receiving unit 3 arranged in a bed B on which the subject U lies, and a subject from these. Amplification of the reflected wave from the subject U received by the irradiation control unit 5 for supplying and controlling the microwave transmitted toward the U, the first microwave transmission / reception unit 2 and the second microwave transmission / reception unit 3 and the input An amplification conversion device 6 that performs digital processing as a signal and a computer 7 for detecting necessary physical information from the input signal are provided. These are connected so that signal transmission is possible.

  The first microwave transmission / reception unit 2 and the second microwave transmission / reception unit 3 further include an irradiation unit (not illustrated) that irradiates microwaves and a reception unit (not illustrated) that receives a reflected wave from the subject U. Yes.

  The amplification conversion device 6 includes a DC amplification unit 8 and an A / D conversion unit 10. Then, for example, a signal value sampled at a sampling frequency of 100 Hz is output to the computer 7. Some or all of these may be built in the computer.

  The computer 7 includes a ROM (Read Only Memory) (not shown) in which programs and data for performing necessary processing are stored, a RAM (Random Access Memory) (not shown) for temporarily storing signal data, ROM A CPU (central processing unit) (not shown) that performs processing according to the physical information measurement program P1 stored in the computer and a display unit (not shown) that displays the calculated physical information are provided.

  The physical information measurement program P1 includes a frequency selection unit 11, an amplitude compression unit 12, a signal analysis unit 13, as functional means (program module) for detecting predetermined physical information from an input signal in which a plurality of biological signals are mixed. It has.

  The frequency selection unit 11 reduces the signal intensity other than the main band of the heartbeat signal (detection target biological signal) or the respiratory signal (detection target biological signal) with respect to the input signal from the amplification conversion device 6, and is so-called filtering. (Bandpass filtering) is executed. For example, as the heartbeat pass band, 0.5 [Hz] is preset for the minimum heartbeat frequency and 3.0 [Hz] is set for the maximum heartbeat frequency. Further, 0.015 [Hz] is set in advance as the minimum frequency for respiration, and 0.5 [Hz] is set in advance as the maximum frequency for respiration.

  The amplitude compression unit 12 compresses only the amplitude of each wave of the input signal having an intensity exceeding a predetermined threshold according to the heartbeat signal or the respiration signal, while the amplitude of the wave having the intensity within the threshold remains unchanged. The process is performed. For example, in the case of a heartbeat signal, the threshold value is set to ± 0.03 [V] when the magnitude of amplitude is displayed in voltage.

  In compression processing, an AGC (Automatic Gain Control) method is introduced, and the peak waveform or valley waveform is multiplied by a coefficient obtained by dividing the threshold value by the maximum value of the peak waveform of the input signal wave or the minimum value of the valley waveform of the wave. Reduce the waveform.

  The signal analyzing unit 13 converts the compressed input signal by, for example, a known fast Fourier transform (FFT) described in Japanese Patent Application Laid-Open No. 2001-257611, Japanese Patent Application Laid-Open No. 2006-258786, and the like. Calculate the intensity of the frequency component. Then, for example, a known process described in paragraph numbers [0043] to [0048] of JP 2010-178933 A is performed to calculate a heart rate and a respiratory rate.

  Next, a physical information measuring method by the physical information measuring apparatus 1 according to the present embodiment will be described with reference to FIG.

  This physical information measuring method includes an irradiation step (S01), a reception step (S02), a frequency selection step (S03), an amplitude compression step (S04), and a signal analysis step (S05).

  In the irradiation step (S01), the subject U is irradiated with microwaves. For example, the microwave of the intensity determined by the irradiation control unit 5 is irradiated from the first microwave transmitting / receiving unit 2 and the second microwave transmitting / receiving unit 3 to the subject U lying on the bed B.

  In the reception step (S02), the microwave reflected from the subject U is received and digital processing is performed. For example, the reflected microwave is received by the first microwave transmission / reception unit 2 and the second microwave transmission / reception unit 3, and is amplified to a predetermined size by the amplification conversion device 6, and the A / D converted input signal is input to the computer 7. Output.

  In the frequency selection step (S03), the signal intensity other than the main band of the heartbeat signal or the respiratory signal is reduced with respect to the input signal. This is processed by the frequency selection unit 11 in the computer 7.

  In the amplitude compression step (S04), only the amplitude of each wave of the input signal having an intensity exceeding a predetermined threshold corresponding to the heartbeat signal or the respiratory signal is compressed with respect to the input signal. The amplitude of the wave is left as it is. For example, the amplitude compression unit 12 performs a process indicated by a broken line in FIG. 3A on an input signal indicated by a solid line in FIG.

  That is, in the case of a heartbeat signal, as shown in FIG. 4A, compression processing is performed over the entire amplitude of each of the peak waveform and valley waveform of the input signal exceeding the threshold value of ± 0.03 [V]. Do. For example, when the peak value of the peak waveform exceeding the above threshold is Pmax [V], 0.03 over the entire peak waveform amplitude from 0 [V] to Pmax [V] and again to 0 [V]. Multiply by a coefficient consisting of / Pmax. As a result, as shown in FIG. 4A, the peak waveform is compressed from a solid line to a broken line.

  On the other hand, as shown in FIG. 3A, compression processing is not performed for waveforms whose amplitude is equal to or smaller than a threshold value ± 0.03 [V]. For this reason, in this region, the waveforms of the solid line and the broken line match.

  Since the output of the respiration signal is about 100 times the heartbeat signal, the amplitude compression step (S04) may be performed first after the reception step (S02), and then the frequency selection step (S03) may be performed. .

  In the signal analysis step (S05), a predetermined analysis is performed using the signal value obtained by the broken line shown in FIG. Thus, for example, as shown by the broken line in FIGS. 3B and 4B, the peak frequency of the heartbeat is calculated (the solid line indicates the frequency analysis result when the amplitude compression process is not performed).

  According to the physical information measuring device 1 and the physical information measuring program P1, the magnitudes of all the amplitudes of the signals separated for each frequency band of the input signal fall within the threshold determined according to the heartbeat signal and the respiratory signal. Even if a body motion signal is mixed in the input signal, for example, even if a body motion signal is mixed in the input signal, it can be set to the same level as the heartbeat signal and the respiratory signal. Can be analyzed.

  Therefore, when analyzing a plurality of biological signals whose frequency components approximate even though there is a difference in intensity, they are not buried in a relatively strong biological signal such as a body motion signal. A biological signal having a relatively weak intensity can be suitably detected. As a result, even if the subject U is in a sleep state where it is difficult to force the patient U to rest, a biological signal can be acquired for a long time without applying a physiological or mental load.

(Second Embodiment)
Next, a second embodiment will be described with reference to FIGS.
In addition, the same code | symbol is attached | subjected to the component similar to 1st embodiment mentioned above, and description is abbreviate | omitted.
The difference between the second embodiment and the first embodiment is that the physical information measurement program P2 of the physical information measurement apparatus 20 according to the present embodiment obtains predetermined physical information from an input signal in which a plurality of biological signals are mixed. As a function means (program module) to detect, as shown in FIG. 5, the 1st determination part 21, the 2nd determination part 22, the measurement exclusion process part 23, and the measurement restart process part 25 are further provided. This is the point.

  The first determination unit 21 determines whether the intensity of the input signal from the amplification conversion device 6 has increased at a first predetermined speed or higher. When the first determination unit 21 determines that the condition is satisfied, the second determination unit 22 determines whether the intensity of the input signal has continued for a first predetermined strength or more and for a first predetermined time or more.

  When the second determination unit 22 determines that the condition is satisfied, the measurement exclusion processing unit 23 interrupts the signal processing in the signal analysis unit 13 for a time during which the condition is continued. The measurement restart processing unit 25 cancels the interruption processing in the measurement exclusion processing unit 23 when the intensity of the input signal decreases at the second predetermined speed or more and continues at the second predetermined intensity or less and the second predetermined time or more. Then, the signal processing in the signal analysis unit 13 is restarted. The first predetermined strength and the second predetermined strength may be the same. In this case, the measurement resumption processing unit 25 cancels the interruption process in the measurement exclusion processing unit 23 when the intensity of the input signal continues below the first predetermined intensity and for the second predetermined time or more.

  This is because, for example, it is difficult to accurately detect a heartbeat signal having a lower intensity than that during a period in which the body motion signal continues to some extent. This is to prevent analysis of etc. Similarly, it is difficult to accurately detect a heartbeat signal or the like having a smaller fluctuation than this during a period in which a body motion signal having a larger fluctuation than the heartbeat signal or the like continues to some extent. It is for not analyzing.

  Next, a physical information measuring method by the physical information measuring apparatus 20 according to the present embodiment will be described with reference to FIG. This physical information measuring method includes an irradiation step (S11), a reception step (S12), a frequency selection step (S13), an amplitude compression step (S14), a determination step (S15), and a signal analysis step (S16). And.

  An irradiation step (S11), a reception step (S12), a frequency selection step (S13), and an amplitude compression step (S14) are respectively an irradiation step (S01) and a reception step (S02) in the physical information measurement method according to the first embodiment. ), The same as the frequency selection step (S03) and the amplitude compression step (S04), both of which are not described here.

  In the determination step (S15), the first determination unit 21 determines whether the intensity of the input signal from the amplification conversion device 6 has increased at a first predetermined speed or more. And when the 1st determination part 21 determines with satisfy | filling conditions, the 2nd determination part 22 determines whether the intensity | strength of the input signal continued more than 1st predetermined intensity | strength and more than 1st predetermined time.

  And when it determines with the 2nd determination part 22 satisfy | filling conditions, the measurement exclusion process part 23 interrupts the analysis of the input signal of this period noting that the body movement continued during this period. On the other hand, when the intensity of the input signal continues for less than the second predetermined intensity and for the second predetermined time or more, the measurement restart processing unit 25 cancels the interruption processing in the measurement exclusion processing unit 23 as returning to the resting state. The signal processing in the signal analysis unit 13 is resumed.

  For example, as shown in FIG. 7A, when the intensity of the input signal is represented by power intensity as a body motion index and the first predetermined intensity is −65 [dBm], it is −65 [dBm] or more. In the case of strength, this period is set as the body movement continuation period, and the subsequent analysis is interrupted. Thereby, as shown in FIG.7 (b), the result close | similar to a Holter electrocardiogram is obtained compared with the case where a body movement continuation period is not excluded.

  On the other hand, if it is less than −65 [dBm], it is determined that the patient is in a resting state, and the process proceeds to the signal analysis step (S16) to detect the heart rate or respiratory rate. Here, since the signal analysis step (S16) is the same as the signal analysis step (S05) in the physical information measurement method according to the first embodiment, the description thereof is omitted.

  According to the physical information measuring device 20 and the physical information measuring program, even when a biological signal having a high intensity such as a body motion signal continues for a predetermined time, the analysis during this period is interrupted and excluded. As a result, it is possible to further improve the analysis reliability of heartbeat signals and respiratory signals.

(Third embodiment)
Next, a third embodiment will be described with reference to FIGS.
In addition, the same code | symbol is attached | subjected to the component similar to other embodiment mentioned above, and description is abbreviate | omitted.
The difference between the third embodiment and the second embodiment is that the physical information measurement program P3 of the physical information measurement apparatus 30 according to the present embodiment obtains predetermined physical information from an input signal in which a plurality of biological signals are mixed. As a functional means (program module) to detect, as shown in FIG. 8, it is further provided with the 3rd determination part 31. FIG.

  The third determination unit 31 determines that the subject U leaves the bed B when the intensity of the plurality of biological signals continues for a third predetermined time or less, which is smaller than the second predetermined intensity, and for a third predetermined time or more. It is determined that

  For example, during the period in which the subject U moves away from the bed B, no body motion signal is input. During this time, neither a heartbeat signal nor a respiration signal is input. Therefore, in order to improve the accuracy of the signal analysis, the analysis of the heartbeat signal and the like is interrupted with this interval being the bed leaving duration.

  Next, a physical information measuring method by the physical information measuring device 30 according to the present embodiment will be described with reference to FIG. The physical information measuring method includes an irradiation step (S21), a reception step (S22), a frequency selection step (S23), an amplitude compression step (S24), a determination step (S25), and a signal analysis step (S26). And.

  The irradiation step (S21), the reception step (S22), the frequency selection step (S23), and the amplitude compression step (S24) are respectively an irradiation step (S01) and a reception step (S02) in the physical information measurement method according to the first embodiment. ), The same as the frequency selection step (S03) and the amplitude compression step (S04), both of which are not described here.

  In the determination step (S25), not only the body movement determination and the rest determination based on the intensity of the input signal, but also the determination by the third determination unit 31 is performed as in the second embodiment. When the third determination unit 31 determines that the condition is satisfied, the measurement exclusion processing unit 32 performs a process of interrupting the analysis of the input signal during this period. On the other hand, when leaving the bed leaving period, the interruption processing in the measurement exclusion processing unit 32 is canceled, and the measurement resumption processing unit 25 resumes the signal processing in the signal analysis unit 13.

  For example, as shown in FIG. 10 (a), when the intensity of the input signal is represented by the power intensity as a body motion index and the third predetermined intensity is -80 [dBm], it is -80 [dBm] or less. In the case of strength, as shown in FIG. 10B, the analysis is interrupted with this period as the bed leaving continuation period.

  Thus, the heart rate or the respiratory rate is detected through the signal analysis step (S26). Here, since the signal analysis step (S26) is the same as the signal analysis step (S05) in the physical information measurement method according to the first embodiment, the description thereof is omitted.

  According to the physical information measuring device 30 and the physical information measuring program, not only when a strong biological signal such as a body motion signal continues for a predetermined time, but the subject U leaves the floor and cannot acquire data, and only noise is generated. By interrupting and eliminating the analysis of the input period, it is possible to further improve the analysis reliability of the heart rate signal and the respiratory signal as a whole.

The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, judgment criteria such as a threshold value at each step in each of the above embodiments are not limited to those exemplified. Further, the biological signal is not limited to the signal described above.

1, 20, 30 Physical information measuring device 11 Frequency selection unit 12 Amplitude compression unit 13 Signal analysis unit 21 First determination unit 22 Second determination unit 23, 32 Measurement exclusion processing unit 25 Measurement restart processing unit 31 Third determination unit P1, P2, P3 Physical information measurement program

Claims (6)

A body information measuring device that detects predetermined body information from an input signal including a plurality of biological signals having different intensities including a biological signal to be detected having periodicity,
An amplitude compression unit that compresses only the amplitude of each wave of the input signal having an intensity exceeding a threshold determined according to the detection target biological signal, while maintaining the amplitude of the wave of the intensity within the threshold as it is; ,
A signal analysis unit that analyzes the output signal from the amplitude compression unit and outputs predetermined body information;
A physical information measuring device comprising:   The compression processing of the amplitude compression unit reduces the waveform by multiplying the peak waveform or the valley waveform by a coefficient obtained by dividing the threshold value by the maximum value of the peak waveform of the wave or the minimum value of the valley waveform of the wave. The physical information measuring device according to claim 1, wherein:   The physical information measuring apparatus according to claim 1, further comprising a frequency selection unit that reduces a signal intensity other than a main band of the detection target biological signal. A first determination unit for determining whether the intensity of the input signal has increased at a first predetermined speed or more;
A second determination unit that determines whether or not the intensity of the input signal has continued for a first predetermined time or more and a first predetermined time or more when it is determined that the first determination unit satisfies a condition;
When it is determined that the second determination unit satisfies the condition, a measurement exclusion processing unit that interrupts signal processing in the signal analysis unit for the duration period; and
A measurement resumption processing unit for canceling the interruption processing by the measurement exclusion processing unit when the intensity of the input signal decreases at a second predetermined speed or more and continues at a second predetermined intensity or less and a second predetermined time or more; ,
The body information measuring device according to any one of claims 1 to 3, further comprising: A third determination unit that determines that the person is getting out of bed when the intensity of the plurality of biological signals continues at a third predetermined intensity or less and a third predetermined time or more;
Even when the third determination unit determines that the condition is satisfied, the measurement exclusion processing unit interrupts the signal processing for the bed leaving duration in the signal analysis unit and determines that the condition is not satisfied, The physical information measuring apparatus according to claim 4, wherein the restart processing unit cancels the interruption processing in the measurement exclusion processing unit. A computer program for causing a computer to function as the physical information measuring device according to any one of claims 1 to 5.

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