JP2020056629A - Biological information detector - Google Patents

Abstract

To provide a biological information detector which can detect information on living bodies including the presence or absence of living bodies.SOLUTION: A biological information detector 1 includes: a detection system 2 for sending a transmission wave made of continuous waves with modulated frequencies to a target object and detecting distance spectrum intensity data showing the intensity in time sequence according to a distance to the object based on the difference in the frequency between the transmission wave and a reflected wave from the object; a calculation unit 40 for calculating differential data on the difference between the result of a moving averaging procedure done on the current distance spectrum intensity data and the result of a moving averaging procedure done on the previous distance spectrum intensity data, the differential data being obtained on a distance-by-distance basis based on the result of detection of the detection system 2; and a determination unit 45 for determining the presence of a living body based on the differential data.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a biological information detecting device using radio waves.

  Conventionally, as a distance measurement method using radio waves, for example, a biological condition detection device using a radar based on the FM-CW (Frequency Modulated Continuous Wave) method (hereinafter, referred to as “FM-CW radar”) has been proposed (see, for example, Japanese Patent Application Laid-Open No. H10-157572). For example, see Patent Document 1).

  The biological condition detection device described in Patent Document 1 transmits a frequency-modulated continuous wave transmission wave to an object including a living body, and based on a frequency difference between the transmission wave and a reflected wave from the object, An FM-CW radar for detecting distance spectrum intensity data indicating the intensity at each predetermined distance to a target in a time-series manner, and extracting a body motion signal based on respiration of a living body from a detection result of the FM-CW radar Extracting means for determining whether the posture of the living body is in the sitting position or the lying position, or determining the respiration of the living body based on the body motion signal.

Japanese Patent No. 5848469

  In addition to the posture and breathing of the living body (usually a person), information on the living body such as the position of the living body in the living room, whether or not it is in the living room (presence / absence), the presence or absence of a fall, and activity information is acquired. There is a request to monitor.

  An object of the present invention is to provide a living body information detecting device capable of detecting information on a living body including presence / absence of a living body.

[1] A frequency-modulated continuous wave transmission wave is transmitted to an object including a living body, and the intensity at each distance to the object is determined based on a frequency difference between the transmission wave and a reflected wave from the object. A detecting unit that detects distance spectrum intensity data indicating in time series,
Based on the detection result of the detection unit, difference data is calculated for each of the distances, the difference between the current distance spectrum intensity data and the result of the moving average processing performed on the immediately preceding distance spectrum intensity data. A calculating unit to perform
A biological information detection device comprising: a presence determination unit configured to determine presence of the living body based on the difference data.
[2] The biological information detection device according to [1], wherein the presence determination unit excludes a change in intensity of a predetermined cycle from determination targets.
[3] a minimum floor detection unit for detecting a minimum noise floor based on a detection result of the detection unit,
The biological information detection device according to [1] or [2], wherein the presence determination unit determines that the living body is present when the difference data is larger than the minimum noise floor.
[4] The calculation unit calculates difference data obtained for each of the distances by dividing at least a nearby area, a detection area, and a distant area in accordance with a concentric distance from itself,
The presence determination unit excludes the difference data when the maximum intensity of the near area or the distant area is larger than the maximum intensity of the detection area, and excludes the difference data in the other detection areas. The living body information detecting device according to any one of [1] to [3], wherein the presence of the living body is determined based on the information.

  ADVANTAGE OF THE INVENTION According to this invention, the information regarding a living body including the presence / absence of a living body can be detected.

FIG. 1 is a plan view showing an example of an indoor place where a biological information detecting device according to an embodiment of the present invention is arranged. FIG. 2 is a block diagram illustrating a configuration example of the biological information detection device according to the present embodiment. FIG. 3 is a diagram illustrating an example of power for each area. FIG. 4 is a diagram illustrating an example of a time-series change in power in a living room. FIG. 5 is a diagram illustrating an example of a time-series change in power when the flap of the air conditioner operates. FIG. 6 is a diagram illustrating an example of a time-series change in power when the cleaning robot in the air conditioner operates.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each of the drawings, components having substantially the same function are denoted by the same reference numerals, and redundant description is omitted.

[Embodiment]
FIG. 1 is a plan view showing an example of an indoor place where a biological information detecting device according to an embodiment of the present invention is arranged.

  In the indoor 100 shown in FIG. 1, there is a living room 101, and a living body information detecting device (hereinafter also referred to as “sensor”) 1 and an air conditioner 102 are arranged on a wall 101 a of the living room 101, and a floor 101 b of the living room 101 is provided. Is provided with a bed 103. In the living room 101, a toilet 104, a door 105, and the like are provided. Note that the sensor 1 may be arranged in another place such as a ceiling or a bed 103 arranged indoors, or may be built in a fixture such as a lighting fixture.

  The sensor 1 detects, for example, biological information of the subject P in the living room 101. “Biological information” refers to information about a living body such as the position of the living body and the state of the living body. The biological information includes, for example, presence / absence of a living room, an activity state, a bed state, a posture, a respiratory rate, a pulse rate, and the like. The subject P is an example of a living body. The living body may be an animal such as a dog or a cat. In addition, the target person P may be plural.

  The detectable distance of the sensor 1 is, for example, 0 to 8 m. A near area (for example, 2 m or less) 121, a detection area (for more than 2 m and 5 m or less) 122, and a far area (for more than 5 m and 8 m or less) 123 are set concentrically according to the distance from the sensor 1. The detection area 122 is an area for detecting biological information. The near area 121 and the far area 123 are areas not intended for detecting biological information. Although the detection area 122 is provided in a part of the detectable distance as described above, this is an example, and the detection area 122 is not necessarily provided.

  FIG. 2 is a block diagram illustrating a configuration example of the sensor 1. The sensor 1 includes a detection system 2, a first processing system 3, a second processing system 4, and a communication unit 5.

  The communication unit 5 transmits the detection result of the biological information obtained by the first processing system 3 and the second processing system 4 to the outside by wire or wirelessly. As the outside, for example, a management center or the like that manages the target person P can be considered. The management center performs operations such as issuing an alarm based on the biological information transmitted from the communication unit 5.

(Configuration of detection system)
The detection system 2 includes an RF radar 20, an I / Q folding synchronous addition unit 21, and a frequency conversion unit 22.

  The RF radar 20 transmits a frequency-modulated continuous wave transmission wave to an object (including a moving object such as a living body and a fixed object such as a bed), receives a reflected wave from the object, and reflects the transmitted wave and the reflected wave. The frequency difference (beat frequency) from the wave is output as an I signal and a Q signal (hereinafter, referred to as “IQ signal”). The transmission wave uses, for example, a 24 GHz band. When the sweep frequency band is set to 200 MHz, the RF radar 20 transmits a transmission wave modulated in a range of 24.05 GHz to 24.25 GHz. Note that the frequency band is not limited to 24 GHz.

  The I / Q folding synchronous adder 21 repeats the superposition of the IQ signals output from the RF radar 20 a predetermined number of times. This improves the S / N ratio of the IQ signal.

  The frequency conversion unit 22 Fourier-transforms the IQ signal output from the I / Q folding synchronous addition unit 21 to indicate the intensity (hereinafter, also referred to as power) for each distance to the target in a time-series manner. Data (hereinafter also referred to as “distance spectrum intensity data”).

(Configuration of first processing system)
The first processing system 3 includes a first difference data calculation unit 30, a spectrum conversion unit 31, a filter unit 32, a position determination unit 33, an area-based power unit 34, an operation determination unit 35, a minimum noise A floor detection unit 36A, a maximum noise floor detection unit 36B, and a normalization processing unit 37 are provided.

  The first difference data calculation unit 30 includes a delay unit 30 a that delays the distance spectrum intensity data output from the frequency conversion unit 22 for a predetermined time (for example, 20.48 ms), and an output of the frequency conversion unit 22. And an adder 30b for adding output data of the delay unit 30a to the data. As a result, difference data in which the difference between the distance spectrum intensity data and the immediately preceding distance spectrum intensity data is obtained for each distance is obtained.

  The spectrum converter 31 obtains power for each of a plurality of continuous frequencies BIN with respect to the difference data from the first difference data calculator 30, and converts the power to a logarithm.

  The filter unit 32 performs moving average processing (processing corresponding to a low-pass filter) on the output data of the spectrum conversion unit 31 for each of a plurality of continuous frequencies BIN, and outputs the processing result (power for each distance) to the first motion. The information is output to the position determination unit 33 as information 32a. Note that the first motion information 32a includes power at all positions. For example, when the living body is located at 4 m, a waveform similar to the solid line in FIG. 4 is obtained.

  The position determination unit 33 determines the subject P based on the first motion information 32a from the filter unit 32 of the first processing system 3 and the second motion information 42a from the filter unit 42 of the second processing system 4. And outputs it to the communication unit 5 as the position information 33a.

  The information (for example, walking) of the subject P that is relatively fast moving 60 times or more per minute is obtained from the filter unit 32 of the first processing system 3, and the subject P is obtained from the filter unit 42 of the second processing system 4. Information on relatively slow movements of P less than 50 times per minute (eg, respiratory rate, etc.) is obtained.

  The first motion information 32a and the second motion information 42a include the time when the power peak occurs and the distance from the sensor 1. Therefore, the position determination unit 33 can detect the current position of the subject P in the living room 101 and the position information 33a such as a change in the position by tracking the time and distance at which the power peak occurs. .

  For example, if the subject P enters the living room 101 and lays down on the bed 103, when entering the living room 101, both the first motion information 32a and the second motion information 42a indicate a high level, When the body motion is lost by lying on the bed 103, the level of the first motion information 32a decreases, and the second motion information 42a indicates a high level.

  The power unit for each area 34 outputs power for each of the areas 121, 122, and 123 by designating a distance range used for calculation. That is, the area-by-area power unit 34 converts the distance spectrum intensity data output from the first difference data calculation unit 30 into distance spectrum intensity data (hereinafter, referred to as “first area motion information”) 34a (hereinafter referred to as “first area motion information”). 4), the first area motion information 34b relating to the near area 121, and the first area motion information 34c relating to the distant area 123.

  The operation determination unit 35 includes the first area motion information 34a to 34c for each of the areas 121, 122, and 123 output from the area-specific power unit 34, and the minimum noise floor 36a detected by the minimum noise floor detection unit 36A (see FIG. 4). ), The presence or absence of the motion of the subject P in the detection area 122 is determined, and the determination result is output to the communication unit 5 as motion information 35a (see FIG. 4).

  That is, when the power in the detection area 122 exceeds the minimum noise floor 36a and further fluctuates beyond the threshold, the operation determination unit 35 determines that the subject P has operated. When the maximum power in the nearby area 121 or the distant area 123 is larger than the maximum power in the detection area 122, the operation determining unit 35 determines that the power of the detection area 122 is higher than the power of the nearby area 121 or the distant area 123. The power of the detection area 122 is excluded from the operation determination as being affected. Thus, for example, as shown in FIG. 3, although the target person P is not present in the detection area 122 and the distant area 123, for example, because another person has moved outside the living room 101, the distant area 123 can be placed. The maximum power is obtained at a distance of 7 m, and the maximum power exceeding the threshold may be obtained at a distance of 4 m in the detection area 122. However, it is possible to avoid erroneous determination that the target person P is present in the distant area 123. it can.

  In addition, when the operation determining unit 35 operates at a predetermined cycle such as a flap that changes the wind direction of the air conditioner 102 or a cleaning robot of the air conditioner 102, the power based on the operation is excluded from the determination target. Note that what is excluded from the determination target is not limited to these.

  The minimum noise floor detector 36A detects the minimum noise floor 36a (see FIG. 4) by tracking the minimum value of the power in the detection area 122. The maximum noise floor detector 36B detects the maximum noise floor (not shown) by tracking the maximum value of the power in the detection area 122. However, the amounts of change of the minimum noise floor and the maximum noise floor are limited so that the values do not change extremely.

  The normalization processing unit 37 evaluates the difference between the minimum noise floor 36a detected by the minimum noise floor detection unit 36A and the maximum noise floor detected by the maximum noise floor detection unit 36B in a plurality of (for example, 10) evaluation values (for example, 10 levels). 0 to 10), and converts the first area motion information 34a in the detection area 122 output from the area-by-area power unit 34 into activity information 37a using normalized evaluation values. The normalization may be performed based on the minimum noise floor 36a and the maximum noise floor measured or predicted in advance.

(Configuration of second processing system)
The second processing system 4 includes a second difference data calculation unit 40, a spectrum conversion unit 41, a filter unit 42, a power unit for each area 44, and an operation determination unit 45. The second difference data calculator 40 is an example of a calculator. The operation determining unit 45 is an example of a presence determining unit.

  The second difference data calculation unit 40 gives a delay of a predetermined time (for example, 20.48 ms) to the distance spectrum intensity data output from the frequency conversion unit 22, and sets the distance output from the frequency conversion unit 22. A moving average unit 40a that performs a moving average process on the spectrum intensity data, and an adding unit 40b that adds the output data of the moving average unit 40a to the output data of the frequency conversion unit 22 are provided. As a result, difference data in which the difference between the distance spectrum intensity data and the immediately preceding distance spectrum intensity data is obtained for each distance is obtained.

  In the moving average process, an average value obtained by averaging N consecutive values in time series is calculated while moving one by one in the time direction. The value of N may be determined according to the frequency of the motion to be detected. In the present embodiment, the value of N is determined such that 10 to 50 breaths per minute can be detected. The moving average process may use a simple moving average or a weighted moving average. By using the weighted moving average, data close to the original data can be obtained. The weighted moving average uses a larger coefficient as soon as possible.

  As in the case of the spectrum conversion unit 41 and the spectrum conversion unit 31 of the first processing system 3, the power is obtained for each of a plurality of continuous frequencies BIN, and is converted into a logarithm.

  The filter unit 42 performs a moving average process (a process corresponding to a low-pass filter) on the output data of the spectrum conversion unit 41 for each of a plurality of continuous frequencies BIN, similarly to the filter unit 32 of the first processing system 3. , And outputs the processing result (power for each distance) to the position determination unit 33 as the second motion information 42a. The second motion information 42a includes the powers of all positions. For example, when the living body is located at 4 m, a waveform similar to the solid line in FIG. 4 is obtained.

  As in the case of the area-based power unit 44 and the area-based power unit 34 of the first processing system 3, the power (intensity) of each of the areas 121, 122, and 123 is calculated by specifying a distance range used for calculation. That is, the area-specific power unit 44 converts the distance spectrum intensity data output from the second difference data calculation unit 40 into distance spectrum intensity data (hereinafter, referred to as “second area motion information”) 44a (hereinafter referred to as “second area motion information”). 4), the second motion information 44b relating to the near area 121, and the second motion information 44c relating to the distant area 123.

  The operation determination unit 45 is based on the second area motion information 44a to 44c for each of the areas 121, 122, and 123 calculated by the power unit 44 for each area and the minimum noise floor 36a detected by the minimum noise floor detection unit 36A. The presence / absence information 45a (see FIG. 4) indicating whether or not the subject P exists in the living room 101 is output. The operation determination unit 45 may determine the presence / absence by comparing the level of the output data of the area-specific power unit 44 with a predetermined threshold value without using the data of the minimum noise floor detection unit 36A.

(Operation of the embodiment)
Next, an example of the operation of the present embodiment will be described with reference to FIGS.

(1) Operation of Subject in Living Room FIG. 4 is a diagram illustrating an example of a time-series change in power in the living room. The horizontal axis in FIG. 4 indicates time, and the vertical axis indicates power (dB: decibel) excluding the operation information 35a and the presence / absence information 45a. When the subject person P opens the door 105 and enters the living room 101, as shown in FIG. 4A, the first area motion information 34a output from the area-by-area power unit 34 of the first processing system 3 and the The power of the second area motion information 44a (for example, breathing) output from the area-by-area power unit 44 of the second processing system 4 increases.

  As shown in FIG. 4A, the activity information 37a output from the normalization processing unit 37 of the first processing system 3 has a large level corresponding to the first area motion information 34a.

  When the entered subject P moves and lays down on the bed 103, the powers of the first area motion information 34a and the second area motion information 44a both decrease as shown in FIG. The level of the first area motion information 34a is lower than that of the second area motion information 44a. This tendency occurs when the body motion of the subject P is slower than the breathing. At this time, the activity information 37a indicates that no activity is taking place.

  When the subject P turns over on the bed 103, the body moves as shown in FIGS. 4C and 4D, so that the powers of the first area movement information 34a and the second area movement information 44a are both instantaneous. Become larger.

(2) Flap Operation of Air Conditioner FIG. 5 is a diagram illustrating an example of a time-series change in power when the flap of the air conditioner 102 operates. The horizontal axis in FIG. 5 indicates time, and the vertical axis indicates power (dB: decibel) excluding the presence / absence information 45a.

  When the subject P opens the door 105 and enters the living room 101, as shown in FIG. 5A, the first area movement information 34a and the second area movement information 44a have a large level. The presence / absence information 45a indicates the presence of a room.

  Thereafter, since the subject P enters the toilet 104 existing in the distant area 123, the presence / absence information 45a indicates absence.

  The subject P performs an operation of activating the air conditioner 102 after exiting the toilet 104, and exits from the door 105. At the moment when the subject P enters the room and performs an operation of activating the air conditioner 102, as shown in FIG. Since the power of the area movement information 34a and the power of the second area movement information 44a both increase, the presence / absence information 45a indicates the presence of a room.

  Although the target person P has left the room, as shown in FIG. 5C, the power of the second area movement information 44a has been increased by the operation of the flap of the air conditioner 102, so the presence / absence information 45a is present in the room. Is shown. The operation determining unit 45 operates the second area motion information 44a at a predetermined cycle, and the level of the first area motion information 34a is smaller than the threshold. When this continues for a predetermined time, the operation determining unit 45 determines that the subject P is absent, and outputs presence / absence information 45a indicating absence. By outputting the presence / absence information 45a after the above state continues for a predetermined time, erroneous determination can be suppressed.

(3) Cleaning Robot in Air Conditioner FIG. 6 is a diagram illustrating an example of a time-series change in power when the cleaning robot in the air conditioner operates. The horizontal axis in FIG. 6 indicates time, and the vertical axis indicates power (dB: decibel) excluding the presence / absence information 45a.

  When the cleaning robot in the air conditioner 102 operates at a certain timing, as shown in FIG. 6A, since the operation is slow, the level of the first area motion information 34a is small, but the level of the second area motion information 44a is low. Since the level is large, the operation determination unit 45 outputs the presence / absence information 45a indicating the presence of the room. When detecting the time of a in FIG. 6, the time of b in which the cleaning robot is stopped, and the time of the next c, the operation determination unit 45 changes the level of the second area motion information 44a by the operation of the cleaning robot. When it is determined that it has become larger, the operation determination unit 45 outputs presence / absence information 45a indicating absence. By outputting the presence / absence information 45a after detecting the operation of the cleaning robot a plurality of times, erroneous determination can be suppressed.

(Effects of Embodiment)
According to the present embodiment, the following effects can be obtained.
(1) Based on the distance spectrum intensity data detected by the detection system 2, the target person P is detected by the second area motion information 44a to 44c obtained by dividing the area P into the near area 121, the detection area 122, and the far area 123. 122 can be determined.
(2) Even if the flap of the air conditioner 102 or the cleaning robot in the air conditioner 102 operates, a change in the intensity of the cycle based on the movement can be excluded from the determination target, so that it is accurately determined whether the target person P exists in the detection area 122. Can be determined.
(3) By determining the difference between the minimum noise floor and the difference data, it is possible to suppress erroneous determination that the subject P exists at the minimum noise floor.

[Modification]
The embodiments of the present invention are not limited to the above-described embodiments, and various modifications and implementations can be made without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 ... biological information detection device (sensor), 2 ... detection system, 3 ... 1st processing system,
4 second processing system, 5 communication unit,
Reference numeral 20: RF radar, 21: I / Q folding synchronous addition unit, 22: frequency conversion unit
30: first difference data calculation unit, 30a: delay unit, 30b: addition unit,
31: spectrum conversion unit, 32: filter unit, 33: position determination unit
33a: position information; 34: power unit for each area; 34a: first area movement information;
35: operation determination unit; 36A: minimum noise floor detection unit;
36B: maximum noise floor detection unit; 37: normalization processing unit; 37a: activity information;
40: second difference data calculation unit, 40a: moving average unit, 40b: addition unit,
41: spectrum conversion unit, 42: filter unit, 44: power unit for each area,
44a: second area movement information, 45: operation determination unit, 45a: presence / absence information,
100: indoor, 101: living room, 101a: wall, 101b: floor, 102: air conditioner,
103: bed, 104: toilet, 105: door, 121: neighborhood area,
122: detection area, 123: distant area, P: subject

Claims (4)

A transmission wave of a frequency-modulated continuous wave is transmitted to an object including a living body, and based on a frequency difference between the transmission wave and a reflected wave from the object, the intensity at each distance to the object is time-series. A detecting unit for detecting the distance spectrum intensity data shown in the diagram,
Based on the detection result of the detection unit, difference data is calculated for each of the distances, the difference between the current distance spectrum intensity data and the result of the moving average processing performed on the immediately preceding distance spectrum intensity data. A calculating unit to perform
Based on the difference data, a presence determination unit that determines the presence of the living body,
A biological information detection device comprising: The existence determination unit excludes the intensity change of a predetermined cycle from the determination target,
The biological information detecting device according to claim 1. The apparatus further includes a minimum floor detection unit that detects a minimum noise floor based on a detection result of the detection unit,
The presence determination unit determines that the living body is present when the difference data is greater than the minimum noise floor,
The biological information detection device according to claim 1. The calculation unit calculates difference data obtained for each of the distances at least in the vicinity area, the detection area, and the distant area according to the concentric distance from the self,
The presence determination unit excludes the difference data when the maximum intensity of the near area or the distant area is larger than the maximum intensity of the detection area, and excludes the difference data in the other detection areas. Based on, to determine the presence of the living body,
The biological information detecting device according to claim 1.