JP2013078413A - Physical information measuring device and physical information measuring method - Google Patents

Physical information measuring device and physical information measuring method Download PDF

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JP2013078413A
JP2013078413A JP2011218925A JP2011218925A JP2013078413A JP 2013078413 A JP2013078413 A JP 2013078413A JP 2011218925 A JP2011218925 A JP 2011218925A JP 2011218925 A JP2011218925 A JP 2011218925A JP 2013078413 A JP2013078413 A JP 2013078413A
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signal
evaluation index
spectral density
channel
channel signal
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JP5578683B2 (en
JP2013078413A5 (en
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Takemi Matsui
岳巳 松井
Masayuki Kagawa
正幸 香川
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Tokyo Metropolitan Univ
公立大学法人首都大学東京
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Abstract

Provided are a body information measuring apparatus and a body information measuring method capable of accurately extracting a periodic detection target biological signal of a detection target even in a measurement environment in which radar opposition to the detection target, a distance, or the like changes. To do.
A first complex signal forming unit for generating a first I channel signal and a first Q channel signal, and a second complex signal forming unit for generating a second I channel signal and a second Q channel signal. A frequency conversion unit 16 that calculates the spectral density of each channel signal, and a peak number selection unit that selects a signal with the smallest number of peaks protruding each spectral density at the same time within the main band of the detection target biological signal. 17, a signal analysis unit 18 that extracts physical information from the selected signal, an evaluation index for selecting a signal having the best spectral density distribution shape, and the number of peaks is the minimum and the evaluation index is the minimum It is assumed that the body information measuring device 20 includes a best shape selection unit 22 that selects a signal to be obtained.
[Selection] Figure 4

Description

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

  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. It has been proposed to receive a microwave and detect a physical state such as a heart rate and a respiratory rate of a subject based on the received microwave (see, for example, Patent Document 1).

  In measurement by a Doppler microwave radar, an I / Q detection method is generally used in which two orthogonal signal components of an In-phase channel (I channel) and a Quadrature-phase channel (Q channel) are obtained as received signals. In this method, two combinations of the received wave and the local wave are prepared by dividing each of the received wave and the local wave, and each combination is mixed by using a mixer, so that the received signal of two channels is converted. obtain.

  At this time, if the body surface part oscillated by the pulse wave is orthogonal to the radar direction, the distance is short, and it is outside the so-called null detection point, the target signal is output to the radar. The heartbeat signal and the respiratory signal are best included. Therefore, when calculating the heart rate and the respiration rate, for example, FFT (Fast Fourier Transform) frequency analysis is performed, and the I channel signal and the Q channel signal are synthesized to improve the extraction accuracy, or null. Extract the channel signal away from the point, detect the regularity (constant frequency) of each signal, and detect the frequency of the target signal corresponding to the heart rate and respiration rate from a mixture of multiple input signals doing.

JP 2000-102515 A

  However, even if the I-channel signal and the Q-channel signal are synthesized or the channel signal that is far from the null point is extracted as in the conventional body information measuring device, the radar is opposed to the vibrating body surface. Under a measurement environment in which sex, distance, etc. change from moment to moment, it is difficult to accurately extract a target periodic heartbeat signal and respiration signal.

  The present invention has been made in view of the above circumstances, and a periodic detection target biological signal possessed by a detection target even in a measurement environment in which the opposition, distance, and the like of the radar with respect to the detection target change from moment to moment. An object of the present invention is to provide a body information measuring device and a body information measuring method capable of accurately extracting the body information.

The present invention employs the following means in order to solve the above problems.
The physical information measuring device according to the present invention includes a first input signal and a first input signal each of which is irradiated with a radio wave from a different position toward a detection target, and includes a detection target biological signal having periodicity and reflected from the detection target. A body information measuring device for detecting predetermined body information from two input signals, wherein the first complex signal forming unit generates a first I channel signal and a first Q channel signal orthogonal to each other from the first input signal. A second complex signal forming unit that generates a second I channel signal and a second Q channel signal orthogonal to each other from the second input signal, the first I channel signal, the first Q channel signal, the first A frequency converter for calculating a spectral density of each of the second I channel signal and the second Q channel signal, the first I channel signal, the first Q channel signal, and the second I channel A peak number selection unit that selects a signal having the smallest number of peaks of each spectral density at the same time within the main band of the detection target biological signal from the signal and the second Q channel signal; and the selected signal And a signal analysis unit that extracts the body information from.

  In addition, the physical information measuring method according to the present invention includes a first input signal that is irradiated with radio waves from different positions toward the detection target and includes a detection target biological signal having periodicity and reflected from the detection target. And a physical information measuring method for detecting predetermined physical information from the second input signal, the first complex signal generating a first I channel signal and a first Q channel signal orthogonal to each other from the first input signal A second complex signal forming step for generating a second I channel signal and a second Q channel signal orthogonal to each other from the second input signal, the first I channel signal, the first Q channel signal, A frequency conversion step of calculating a spectral density of each of the second I channel signal and the second Q channel signal; and the first I channel signal and the first Q channel A peak for selecting a signal having the smallest number of peaks of each spectral density at the same time in a frequency region including the detection target biological signal from a signal, the second I channel signal, and the second Q channel signal And a signal analyzing step of extracting the physical information from the selected signal.

  Here, when the peaks are arranged in order of increasing peak values on the same spectral density distribution diagram, the n-th peak is the n + 1-th peak with respect to a predetermined numerical value α (for example, 3.0). When there is a minimum integer n that is α times larger than that, let n be the “number of protruding peaks”. When n exceeds a certain integer (for example, 5), the number of peaks is 5.

  The present invention is more prominent because the input signal with a smaller number of peaks having a spectral density is less likely to be disturbed by body movement, and the generation of harmonics and intermodulation waves. As a result, the detection target biological signal can be detected with high accuracy. It is intended to extract highly accurate body information by analyzing a detection target biological signal based on a signal having a spectral density that minimizes the number of peaks.

  Further, the physical information measuring device according to the present invention is the physical information measuring device, wherein the spectral density distribution shape is best from a plurality of the channel signals in which the number of protruding peaks of the spectral density is 1. Second evaluation for selecting a signal having the best distribution shape of the spectral density from a first evaluation index for selecting a signal and a plurality of the channel signals in which the number of protruding peaks of the spectral density is 2. An index and a third evaluation index for selecting a signal having the best distribution shape of the spectral density from the plurality of channel signals in which the number of protruding peaks of the spectral density is 3. The evaluation index, the second evaluation index, and the third evaluation index are compared, and a signal having a spectral density that minimizes the number of peaks and minimizes the evaluation index is selected. Characterized in that it includes the best shape selection unit for.

  Further, the physical information measuring method according to the present invention is the physical information measuring method, wherein the spectral density distribution shape is best from a plurality of the channel signals in which the number of protruding peaks of the spectral density is 1. Second evaluation for selecting a signal having the best distribution shape of the spectral density from a first evaluation index for selecting a signal and a plurality of the channel signals in which the number of protruding peaks of the spectral density is 2. An index and a third evaluation index for selecting a signal having the best distribution shape of the spectral density from the plurality of channel signals in which the number of protruding peaks of the spectral density is 3. The evaluation index, the second evaluation index, and the third evaluation index are compared, and a signal having a spectral density that minimizes the number of peaks and minimizes the evaluation index is selected. Characterized in that it and a best shape selection step of.

  Here, “the distribution shape of the spectral density is the best” means that even if the input signal has the same spectral density with the number of protruding peaks, the peak of the spectral density is steeper or the maximum peak value is the second largest. This means a distribution state in which there is a peak having a larger difference between peaks compared to the peak value.

  Further, the physical information measuring device according to the present invention is the physical information measuring device, wherein the fourth evaluation index is set for a plurality of the channel signals in which the number of protruding peaks of the spectral density is 4 or more. The best shape selection unit compares the first evaluation index, the second evaluation index, the third evaluation index, and the fourth evaluation index, and has the smallest number of peaks and the evaluation index It is characterized in that the signal having the smallest spectral density is selected.

  Further, the physical information measuring method according to the present invention is the physical information measuring method, wherein the fourth evaluation index is set for a plurality of the channel signals in which the number of protruding peaks of the spectral density is 4 or more. The best shape selection step compares the first evaluation index, the second evaluation index, the third evaluation index, and the fourth evaluation index, and has the smallest number of peaks and the evaluation index It is characterized in that the signal having the smallest spectral density is selected.

  In the present invention, since the input signal having the best spectral density distribution shape includes the detection target biological signal with higher accuracy, the spectral density distribution is based on the evaluation index corresponding to the number of protruding peaks. An input signal having the best shape is selected and more suitable body information is extracted by using such a signal.

  Further, the physical information measuring device according to the present invention is the physical information measuring device, wherein the best shape selecting unit is provided when there are a plurality of signals having a spectral density that minimizes the number of peaks and minimizes the evaluation index. Is characterized in that one signal is selected in the order of the first I channel signal, the first Q channel signal, the second I channel signal, and the second Q channel signal.

  Further, the physical information measuring method according to the present invention is the physical information measuring method, wherein when there are a plurality of signals having a spectral density at which the number of peaks is minimum and the evaluation index is minimum, the best shape step is performed. One signal is selected in the order of the first I channel signal, the first Q channel signal, the second I channel signal, and the second Q channel signal.

  In the present invention, when there are a plurality of signals having the smallest number of peaks and the smallest evaluation index, for example, a first Q channel signal and a second Q channel signal, one of the channel signals is selected. The priority order is determined (in this case, the first Q channel signal is selected). By determining the priority order in this way, it is possible to ensure system consistency (here, system integrity integrity in the sense that the result is always the same for the same input signal group). .

  The physical information measuring device according to the present invention is the physical information measuring device, further comprising a drive unit that changes the irradiation direction of the radio wave to the detection target.

  The physical information measuring method according to the present invention is the physical information measuring method, further comprising an adjusting step of changing the irradiation direction of the radio wave with respect to the detection target.

  The present invention detects the detection target signal accurately when the detection target moves actively, for example, when the surface of the vibrating detection target deviates from the irradiation range of the radar, or when the microwave is reflected in a direction that the radar cannot detect. Even if this is not possible, measurement can be performed again by changing the direction of microwave irradiation to the detection target so that the detection target biological signal can be received, and measurement can be continued as much as possible.

  ADVANTAGE OF THE INVENTION According to this invention, the periodic detection target biosignal which a detection target has can be accurately extracted even in the measurement environment where the opposition, distance, etc. of the radar with respect to the detection target change every moment.

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. (A) The number of protruding peaks is one spectral density, (b) the number of protruding peaks is two spectral densities, and (c) the number of protruding peaks is 3 by the body information measuring apparatus according to the first embodiment of the present invention. It is a graph which shows one spectral density and (d) the spectral density whose number of protrusive peaks is 4 or more. 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 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. (A) Heart rate measurement result by Holter electrocardiograph, (b) Heart rate measurement result by physical information measuring device according to the present invention, (c) Body movement occurrence status at the same time 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 body information measuring apparatus 1 according to the present embodiment includes a first radar 2 (a first microwave transmitting / receiving member or a first microwave transmitting / receiving member) disposed at a different position in a bed B on which a subject (test object) U lies. Also referred to as one radar antenna. The same applies hereinafter.) And the second radar 3 (also referred to as a second microwave transmitting / receiving member or second radar antenna. The same applies hereinafter) and microwaves transmitted from these to the subject U. (Radio wave) is supplied and controlled, and the transmission / reception control unit 5 that performs reception processing of the input signal reflected from the subject U, the amplification conversion device 6 that amplifies the received input signal and performs digital processing, and the input signal And a computer 7 for detecting necessary body information. These are connected so that signal transmission is possible.

  A subject detection member (not shown) for detecting the subject U lying on the bed B may be arranged on the upper surface of the bed B. The subject detection member is, for example, a sheet-like sensor that detects whether or not the subject U is away from the bed B based on the weight (body weight) of the subject U, a so-called bed sensor (an heel sensor). ). As for the bed leaving sensor, for example, a known product (“Technos Japan Co., Ltd. | For falling / falling measures! Bed Call”, “online”, September 9, 2003, Technos Japan Co., Ltd., “January 2009 16-day search ”, URL: http://www.technosj.co.jp/alarm/bc.html).

  Each of the first radar 2 and the second radar 3 further includes an irradiation unit (not shown) that irradiates microwaves and a reception unit (not shown) that receives a reflected wave from the subject U. That is, the transmission microwave irradiated from the irradiation unit of the first radar 2 hits the subject U and becomes the first input signal (reflected wave) including the biological signal of the subject U to the reception unit of the first radar 2. Received. The transmission microwave irradiated from the irradiation unit of the second radar 3 hits the subject U and is received by the receiving unit of the second radar 3 as a second input signal including the biological signal of the subject U. 1 (FIGS. 4 and 6) shows the heart rate of the subject U in a state where the first radar 2 and the second radar 3 described above are facing the subject U on the bed B. In order to obtain (information), it is shown that the left and right sides of the chest of the subject U are set in advance at positions where they can be measured.

  The transmission / reception control unit 5 is for controlling that the first radar 2 and the second radar 3 transmit microwaves and receive reflected waves. The transmission / reception controller 5 includes a ROM (read only memory) (not shown) in which programs and data for performing necessary processing are stored, and a RAM (random access memory) (not shown) for temporarily storing signal data. A CPU (Central Processing Unit) (not shown) that performs predetermined processing stored in a ROM or the like. The first radar 2 and the second radar 3 are configured by a hardware circuit and software (not shown) as functional means for detecting the first input signal and the second input signal received from the subject U. A complex signal forming unit 8 and a second complex signal forming unit 10 are provided.

The first complex signal forming unit 8 obtains two orthogonal signal components of the above-described In-phase channel (I channel) and Quadrature-phase channel (Q channel) from the first input signal (reflected wave). Thus, a phase detection circuit (not shown) for demodulating the first input signal as an IF signal (Intermediate Frequency) and a local transmitter (not shown) are provided. Then, the difference between the first input signal (received wave) and the reference signal (local wave) of the local transmitter is extracted as an IF signal by a frequency mixer. At this time, two signals of a signal in phase with the first input signal and a signal delayed by 90 degrees are generated. Here, the in-phase component of the first input signal is the first I channel signal, and the quadrature component is the first Q channel signal. I channel signal, Q
Each channel signal becomes a real component and an imaginary component in the complex signal representation of the output signal. The second complex signal forming unit 10 also has the same configuration as the first complex signal forming unit 8, and similarly to the first complex signal forming unit 8, the second I channel orthogonal to each other from the second input signal (reflected wave). A signal and a second Q channel signal are generated.

  The amplification conversion device 6 includes a DC amplification unit 11 and an A / D conversion unit 12 (for example, Japanese Patent No. 465228). The direct current amplifying unit 11 amplifies the first I channel signal, the first Q channel signal, the second I channel signal, and the second Q channel signal. The A / D converter 12 converts the signal amplified by the DC amplifier 11 from an analog signal to a digital signal. For example, the amplification conversion device 6 sends the signal value sampled at a sampling frequency of 100 Hz to the computer 7 from each of the first I channel signal, the first Q channel signal, the second I channel signal, and the second Q channel signal, for example. Output. In other words, the first I channel signal, the first Q channel signal, the second I channel signal, and the second Q channel signal are subjected to predetermined processing by the DC amplification unit 11 and the A / D conversion unit 12 of the amplification conversion device 6. The signal subjected to (amplification and conversion) and subjected to the predetermined processing is output to the computer 7. A part or all of the transmission / reception control unit 5 and the amplification conversion device 6 may be built in the computer.

  The computer 7 includes a ROM (not shown) in which a program and data for performing necessary processing are stored, a RAM (not shown) in which signal data is temporarily stored, a physical information measurement program stored in the ROM, and the like. A CPU (not shown) that performs a corresponding process and a display unit (not shown) that displays the calculated physical information are provided.

  The computer 7 includes a frequency selector 13 and an amplitude compressor 15 as functional means for detecting predetermined body information from the first input signal (reflected wave) and the second input signal (reflected wave) in which a plurality of biological signals are mixed. And a program including a frequency conversion unit 16, a peak number selection unit 17, and a signal analysis unit 18. These are realized by hardware circuits and software (not shown).

  The frequency selection unit 13 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 signal from the amplification conversion device 6. And the frequency selection part 13 performs what is called filtering (band pass filtering) (for example, refer patent 40405394 gazette). 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 15 is not shown in order to easily extract a heartbeat signal and a respiration signal from a first input signal (reflected wave) and a second input signal (reflected wave) in which a plurality of biological signals are mixed. Gain Control) circuit, compresses only the amplitude of each wave of the input signal whose intensity exceeds a predetermined threshold according to the heartbeat signal and the respiratory signal, while the amplitude of the wave of the intensity within the threshold remains unchanged It is a functional means for performing a process for setting a state. 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.

  As the compression processing by the AGC circuit, the waveform is reduced by multiplying the peak waveform or valley waveform by a coefficient obtained by dividing the threshold value by the maximum value of the peak waveform of the input signal or the minimum value of the valley waveform of the wave.

  The frequency conversion unit 16 uses a known fast Fourier transform (FFT) described in, for example, Japanese Patent Application Laid-Open No. 2001-257611, Japanese Patent Application Laid-Open No. 2006-258786, or the like from each compressed signal. It is a functional means for calculating the spectral density via Note that FFT is an algorithm for calculating a discrete Fourier transform (DFT) at high speed on a computer.

  The peak number selection unit 17 calculates the main band of the heart rate signal or the respiratory signal from the waveforms of the spectral densities of the first I channel signal, the first Q channel signal, the second I channel signal, and the second Q channel signal at the same time. It is a functional means for selecting a signal that minimizes the number of protruding peaks. The locus of the spectral density waveform as shown in FIG. 3 is displayed on a display unit (not shown) of the computer 7. Here, the “number of prominent peaks” refers to the order in which the peak values are large as described above, after setting the maximum output value within a predetermined frequency step size to “peak” on the same spectral density distribution diagram. , When there is a minimum integer n in which the n-th peak is α times larger than the n + 1-th peak with respect to a predetermined numerical value α (for example, 3.0), Is the “number of protruding peaks”.

  For example, the signal analysis unit 18 performs a known process described in paragraphs [0043] to [0048] of Japanese Patent Application Laid-Open No. 2010-178933, and calculates a heart rate and a respiration rate from the spectral density of the selected signal. .

  Next, a physical information measuring method by the physical information measuring apparatus 1 according to this embodiment will be described.

  As shown in FIG. 2, the physical information measuring method includes an irradiation step (S01), a receiving step (S02), a first complex signal forming step (S03), a second complex signal forming step (S04), A frequency selection step (S05), an amplitude compression step (S06), a frequency conversion step (S07), a peak number selection step (S08), and a signal analysis step (S09) are provided.

  In the irradiation step (S01), the first radar 2 and the second radar 3 irradiate the subject U lying on the bed B with a microwave having a predetermined intensity determined by the transmission / reception control unit 5.

  In the receiving step (S02), the first radar 2 and the second radar 3 receive the first input signal (reflected wave) and the second input signal (reflected wave), which are reflected when the above-described microwave hits the subject U, respectively.

  In the first complex signal forming step (S03), the first complex signal forming unit 8 generates a first I channel signal and a first Q channel signal that are orthogonal to each other from the first input signal. In the second complex signal forming step (S04), the second complex signal forming unit 10 generates a second I channel signal and a second Q channel signal that are orthogonal to each other from the second input signal. Then, the first I channel signal, the first Q channel signal, the second I channel signal, and the second Q channel signal created here are each amplified to a predetermined magnitude and A / D converted by the amplification converter 6. The result is output to the computer 7.

  In the frequency selection step (S05), the signal intensity other than the main band of the heartbeat signal or the respiratory signal is reduced with respect to the first I channel signal, the first Q channel signal, the second I channel signal, and the second Q channel signal. To do. This is processed by the frequency selection unit 13 in the computer 7.

  In the amplitude compression step (S06), the amplitude compression unit 15 responds to the heartbeat signal and the respiratory signal for the first I channel signal, the first Q channel signal, the second I channel signal, and the second Q channel signal. Only the amplitude of each wave of the input signal having an intensity exceeding a predetermined threshold is compressed, while the amplitude of the wave having an intensity within the threshold is left as it is.

  Since the output of the respiratory signal is about 100 times that of the heartbeat signal, the body motion signal is first removed in the amplitude compression step (S06) after the reception step (S02), and then the frequency selection step (S03) is performed. You may carry out.

  In the frequency conversion step (S07), the frequency converter 16 calculates the spectral densities of the first I channel signal, the first Q channel signal, the second I channel signal, and the second Q channel signal.

  In the peak number selection step (S08), the peak number selection unit 17 distributes the spectral densities of the first I channel signal, the first Q channel signal, the second I channel signal, and the second Q channel signal at the same time. To select the signal that minimizes the number of prominent peaks in the main band of the heart rate signal or respiratory signal. For example, when the spectral density as shown in FIGS. 3A to 3D is obtained, one signal shown in FIG. 3A having the smallest number of protruding peaks is selected.

  In the signal analysis step (S09), the signal analysis unit 18 calculates the heart rate and the respiration rate based on the signal having the selected spectral density.

  According to the physical information measuring apparatus 1 and the physical information measuring method, the spectral densities of the four signals of the first I channel signal, the first Q channel signal, the second I channel signal, and the second Q channel signal are compared. Then, a signal having a spectral density that minimizes the number of protruding peaks can be selected, and analysis can be performed based on this signal.

  Therefore, the influence of the change is reduced even in a measurement environment in which the opposition of the first radar 2 and the second radar 3 to the subject U, the distance to the subject U, and the like change from moment to moment due to the body movement of the subject U. Thus heart rate and respiratory rate can be extracted with high accuracy.

(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 computer 21 of the physical information measuring apparatus 20 according to the present embodiment further includes a best shape selection unit 22 as shown in FIG. This is the point.

  When the number of peaks with protruding spectral density is the same between the first I channel signal, the first Q channel signal, the second I channel signal, and the second Q channel signal, the best shape selection unit 22 The first evaluation index, the second evaluation index, or the third evaluation index applied according to the number of protruding peaks is calculated, and the shape of the spectral density distribution is further determined from signals having the same number of protruding peaks. Select the signal with the best spectral density.

  Here, the first evaluation index selects a signal having the best shape of the spectral density distribution from a plurality of signals having a number of peaks having a prominent spectral density within a range of 0 to 1, for example, The power amount of one protruding peak is set to approach zero (the shape of the spectral density distribution is the best) as it approaches the value of the total power amount of the entire main band of the heartbeat signal or respiratory signal. The second evaluation index selects a signal having the best shape of the spectral density distribution from a plurality of signals having two spectral peak peaks in the range of 1 to 2, for example, the highest peak. The smaller the peak value that protrudes second than the peak value, the closer the value is to 1 (the shape of the spectral density distribution is the best).

  The third evaluation index selects a signal having the best shape of the spectral density distribution from a plurality of signals having a number of peaks with prominent spectral densities in the range of 2 to 4, for example, the most prominent. The smaller the peak value that protrudes second from the peak value, and the smaller the peak value that protrudes third from the most prominent peak value, the closer to 2 (the spectral density distribution). (The shape is the best). Then, the best shape selection unit 22 selects a signal having a spectral density distribution that minimizes the evaluation index.

  Note that the fourth evaluation is calculated by comparing the magnitudes of the protruding peak values as described above with respect to a signal in which the number of peaks with protruding spectral density is 4 or more, or set to a predetermined value in advance. An index may be further provided. Then, the best shape selection unit 22 may select a signal having a spectral density distribution that minimizes the evaluation index among the first evaluation index, the second evaluation index, the third evaluation index, and the fourth evaluation index. . Hereinafter, the case where the computer 21 includes up to the fourth evaluation index will be described.

  At this time, when there are a plurality of signals having a spectral density that minimizes the number of peaks and minimizes the evaluation index, the best shape selection unit 22 defines a priority order for selecting one signal. That is, the best shape selection unit 22 selects one signal in the order of the first I channel signal, the first Q channel signal, the second I channel signal, and the second Q channel signal. For example, when the signals having the spectral density with the smallest number of peaks and the smallest evaluation index are the first Q channel signal and the second Q channel signal, the first Q channel signal is selected.

  Next, a physical information measuring method by the physical information measuring device 20 according to the present embodiment will be described.

  As shown in FIG. 5, the physical information measuring method includes an irradiation step (S01), a receiving step (S02), a first complex signal forming step (S03), a second complex signal forming step (S04), A frequency selection step (S05), an amplitude compression step (S06), a frequency conversion step (S07), a peak number selection step (S08), a best shape selection step (S20), a signal analysis step (S09), It has.

  In the best shape selection step (S20), the best shape selection unit 22 calculates the first evaluation index, the second evaluation index, the third evaluation index, or the fourth evaluation index according to the number of peaks having a prominent spectral density. Then, the signal having the best spectral density distribution shape is selected from among the signals having the same number of peaks.

  Here, the first evaluation index is, for example, V = 1− (P1 / Pt) (P1 is a peak value, and Pt is the entire main band of a heartbeat signal or a respiratory signal with respect to the spectral density shown in FIG. (Total power). That is, the evaluation index V approaches 0 as P1 approaches Pt (there is no other peak in the corresponding band and one projecting peak has a steeper shape).

  The second evaluation index is, for example, V = 1 + (P2 / P1) (P1 is the larger peak value of the two protruding peaks, and P2 is the smaller of the spectral densities shown in FIG. Peak value). That is, the evaluation index V approaches 1 as the difference between the two peak values increases.

  The third evaluation index is, for example, V = 2 + (P2 / P1) + (P3 / P1) (P1 is the largest peak value among the three protruding peaks with respect to the spectral density shown in FIG. , P2 is represented by the second largest peak value, and P3 is represented by the third largest peak value). That is, the evaluation index V approaches 2 as the most prominent peak value is larger than the other peak values.

The fourth evaluation index is for a spectral density having four or more protruding peaks as in the spectral density shown in FIG. 3D, and is set to a constant value of 5.
Then, each evaluation index V corresponding to the number of peaks with prominent spectral densities is calculated, and a signal having the smallest value of V is sent to the signal analysis step (S09).

  At this time, when there are a plurality of signals having a spectral density that minimizes the number of peaks and minimizes the evaluation index, the first I channel signal, the first Q channel signal, the second I channel signal, and the second Q channel signal The first signal is selected in the following order.

  According to the physical information measuring device 20 and the physical information measuring method, even with input signals having the same spectral density with the number of protruding peaks, the spectral density distribution shape is better (a steeper peak, or between other peak values). Input signal can be selected, and as a result, a signal including a more suitable heart rate signal and respiration signal can be selected, and heart rate and respiration rate can be extracted with higher accuracy. be able to.

(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 1st embodiment mentioned above, and description is abbreviate | omitted.
The difference between the third embodiment and the second embodiment is that the physical information measuring device 30 according to the present embodiment further includes a drive unit 31 as shown in FIG.

  The drive unit 31 further includes a drive mechanism unit 32 disposed in the vicinity of each of the first radar 2 and the second radar 3 and a drive control unit 35 disposed in the computer 33. The drive mechanism unit 32 further includes a known drive source (not shown) and a mechanism unit that transmits a driving force from the drive source.

  The drive control unit 35 can detect a heartbeat signal or a respiratory signal in the first I channel signal, the first Q channel signal, the second I channel signal, and the second Q channel signal generated from the reflected wave from the subject U. When the level is not input, the driving source is controlled by calculating the moving angles of the first radar 2 and the second radar 3 with respect to the subject U required until each signal becomes a detectable level.

  The drive unit 31 is not only in a state in which the target heartbeat signal or respiration signal is not input to the first radar 2 and the second radar 3 at a detectable level, but also in the peak of the spectral density in the second embodiment. May be operated when there is no signal of 3 or less and the number of protruding peaks of 4 or more continues for a certain time or more.

  Next, a physical information measuring method by the physical information measuring device 30 according to the present embodiment will be described.

  As shown in FIG. 7, the physical information measuring method includes an irradiation step (S01), a receiving step (S02), a first complex signal forming step (S03), a second complex signal forming step (S04), Frequency selection step (S05), amplitude compression step (S06), frequency conversion step (S07), peak number selection step (S08), best shape selection step (S20), adjustment step (S30), signal An analysis step (S09).

  In the adjusting step (S30), the heartbeat signal or the respiratory signal can be detected in the first I channel signal, the first Q channel signal, the second I channel signal, and the second Q channel signal in the receiving step (S02). This is carried out when no signal is input or when there is no signal having a peak number of protruding spectral density of 3 or less in the second embodiment and the number of protruding peaks of 4 or more continues for a certain time or longer. At this time, the driving unit 31 adjusts the irradiation angle of the first radar 2 and the second radar 3 to the subject U to improve the reception state.

  According to the body information measuring device 30 and the body information measuring method, the body surface where the body position of the subject U moves and vibrates due to the pulse wave, or the body surface that periodically moves due to respiratory motion is the first. When it is out of the irradiation range of the radar 2 and the second radar 3, the irradiation angle of the first radar 2 and the second radar 3 can be changed so that it can be detected again. Measurement can be performed.

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, the judgment criteria such as the evaluation index at each step in the above embodiments are not limited to those exemplified. Further, the biological signal is not limited to the signal described above. In addition, the subject need not be lying on the bed alone, and may be measured using other means such as a massage chair.

  The heart rate was measured using the body information measuring apparatus according to the present invention. The result is shown in FIG. Compared with the Holter electrocardiograph (FIG. 8 (a)), which is a classic heart rate measurement, measurement was possible without significant difference. Further, as shown in FIG. 8 (c), weak pulse wave vibration data could be detected even when there was a high frequency of body movement.

  The present invention is useful when a doctor, a nurse, or the like confirms the safety of an inpatient in a hospital room in a hospital such as an examination room or a nurse station or outside the hospital when going out or returning home. Further, for example, it is useful when a home caregiver confirms the safety of a care recipient (care recipient) in a separate room at home or in a remote place when going out. It is also useful when observing in a non-contact state, for example, for the study of the ecology of animals such as bears hibernating in a zoo.

1, 20, 30 Physical information measuring device 8 First complex signal forming unit 10 Second complex signal forming unit 16 Frequency converting unit 17 Peak number selecting unit 18 Signal analyzing unit 22 Best shape selecting unit 31 Driving unit

Claims (10)

  1. Predetermined physical information is obtained from a first input signal and a second input signal that are each reflected from the detection target including a detection target biological signal that is irradiated with radio waves from different positions toward the detection target. A body information measuring device to detect,
    A first complex signal generator for generating a first I channel signal and a first Q channel signal orthogonal to each other from the first input signal;
    A second complex signal forming unit for generating a second I channel signal and a second Q channel signal orthogonal to each other from the second input signal;
    A frequency converter for calculating a spectral density of each of the first I channel signal, the first Q channel signal, the second I channel signal, and the second Q channel signal;
    From the first I-channel signal, the first Q-channel signal, the second I-channel signal, and the second Q-channel signal, the prominent peaks of each spectral density at the same time within the main band of the detection target biological signal A peak number selection unit for selecting a signal having the smallest number of
    A signal analyzer that extracts the physical information from the selected signal;
    A physical information measuring device comprising:
  2. A first evaluation index for selecting a signal having the best distribution shape of the spectral density from the plurality of channel signals in which the number of protruding peaks of the spectral density is 1.
    A second evaluation index for selecting a signal having the best distribution shape of the spectral density from the plurality of channel signals in which the number of protruding peaks of the spectral density is 2.
    A third evaluation index for selecting a signal having the best distribution shape of the spectral density from the plurality of channel signals in which the number of protruding peaks of the spectral density is 3.
    With
    A best shape selection unit that compares the first evaluation index, the second evaluation index, and the third evaluation index, and selects a signal having a spectral density that minimizes the number of peaks and minimizes the evaluation index; The physical information measuring device according to claim 1, further comprising:
  3. A fourth evaluation index set for a plurality of the channel signals in which the number of peaks of the spectral density is 4 or more,
    The best shape selection unit compares the first evaluation index, the second evaluation index, the third evaluation index, and the fourth evaluation index, and the number of the peaks is minimized and the evaluation index is minimized. The physical information measuring apparatus according to claim 2, wherein a signal having a spectral density is selected.
  4.   When there are a plurality of signals having a spectral density at which the number of peaks is minimum and the evaluation index is minimum, the best shape selection unit includes the first I channel signal, the first Q channel signal, and the second I channel. 4. The physical information measuring apparatus according to claim 2, wherein one signal is selected in the order of a signal and the second Q channel signal.
  5.   The physical information measuring apparatus according to claim 1, further comprising a drive unit that changes the irradiation direction of the radio wave with respect to the detection target.
  6. Predetermined physical information is obtained from a first input signal and a second input signal that are each reflected from the detection target including a detection target biological signal that is irradiated with radio waves from different positions toward the detection target. A physical information measurement method for detecting,
    A first complex signal forming step of generating a first I channel signal and a first Q channel signal orthogonal to each other from the first input signal;
    A second complex signal forming step for generating a second I channel signal and a second Q channel signal orthogonal to each other from the second input signal;
    A frequency conversion step of calculating a spectral density of each of the first I channel signal, the first Q channel signal, the second I channel signal, and the second Q channel signal;
    From the first I channel signal, the first Q channel signal, the second I channel signal, and the second Q channel signal, each of the spectral densities at the same time within a frequency region including the detection target biological signal A peak number selection step for selecting the signal with the smallest number of peaks,
    A signal analysis step of extracting the physical information from the selected signal;
    A body information measuring method comprising:
  7. A first evaluation index for selecting a signal having the best distribution shape of the spectral density from the plurality of channel signals in which the number of protruding peaks of the spectral density is 1.
    A second evaluation index for selecting a signal having the best distribution shape of the spectral density from the plurality of channel signals in which the number of protruding peaks of the spectral density is 2.
    A third evaluation index for selecting a signal having the best distribution shape of the spectral density from the plurality of channel signals in which the number of protruding peaks of the spectral density is 3.
    With
    The best shape selection step of comparing the first evaluation index, the second evaluation index, and the third evaluation index to select a signal having a spectral density that minimizes the number of peaks and minimizes the evaluation index. The physical information measuring method according to claim 6, comprising: a physical information measuring method according to claim 6.
  8. A fourth evaluation index set for a plurality of the channel signals in which the number of peaks of the spectral density is 4 or more,
    The best shape selection step compares the first evaluation index, the second evaluation index, the third evaluation index, and the fourth evaluation index to minimize the number of peaks and minimize the evaluation index. The physical information measuring apparatus according to claim 7, wherein a signal having a spectral density is selected.
  9.   When there are a plurality of signals having a spectral density at which the number of peaks is minimum and the evaluation index is minimum, in the best shape selection step, the first I channel signal, the first Q channel signal, and the second I channel The physical information measuring device according to claim 7 or 8, wherein one signal is selected in the order of a signal and the second Q channel signal.
  10. The physical information measuring method according to claim 6, further comprising an adjustment step of changing the irradiation direction of the radio wave with respect to the detection target.

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