(12) United States Patent
`US 8,177,720 B2
`(10) Patent N0.:
`Nanba et al.
`
`(45) Date of Patent: May 15, 2012
`
`US008177720B2
`
`(54) APPARATUS FOR DETECTING VITAL
`FUNCTIONS, CONTROL UNIT AND PULSE
`WAVE SENSOR
`
`(75)
`
`Inventors: Shinji Nanba, Kariya (JP); Toshiaki
`Shiomi, Nagoya (JP)
`
`(73) Assignees: DENSO CORPORATION, Kariya (JP);
`Toshiaki Shiomi, Nagoya (JP)
`
`( * ) Notice:
`
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 1342 days.
`
`(21) Appl.No.: 11/802,607
`
`(22)
`
`Filed:
`
`May 24, 2007
`
`.................. 600/485
`
`2/2005 Ohsaki et a1.
`6,856,829 B2
`l2/2002 Nishii et a1.
`2002/0183627 A1 *
`8/2004 Nagai et a1.
`2004/0162499 A1
`4/2006 Coyle
`2006/0074334 A1
`FOREIGN PATENT DOCUMENTS
`A-7-000376
`l/l995
`A-8-l73403
`7/1996
`A-9-098964
`4/1997
`A-2003-000552
`l/2003
`A-2003-038460
`2/2003
`A-2005-l99078
`7/2005
`
`JP
`JP
`JP
`JP
`JP
`JP
`
`OTHER PUBLICATIONS
`
`Office Action dated Aug. 15, 2008 from Chinese Patent Office in
`corresponding CN Patent Application No. 2007101087680 (and
`English Translation).
`Office Action mailed on Jul. 5, 2011 in the corresponding Japanese
`Patent application No. 2006-152354 (English translation enclosed).
`
`(65)
`
`(30)
`
`Prior Publication Data
`
`US 2007/0282227 A1
`
`Dec. 6, 2007
`
`* cited by examiner
`
`Primary Examiner 7 Miranda Le
`Assistant Examiner 7 Tho Tran
`
`Foreign Application Priority Data
`
`(74) Attorney, Agent, or Firm 7 Posz Law Group, PLC
`
`May 31, 2006
`
`(JP) ................................. 2006-152354
`
`(57)
`
`ABSTRACT
`
`(51)
`
`Int. Cl.
`(2006.01)
`A6IB 5/02
`(52) US. Cl.
`........................................ 600/483; 600/484
`(58) Field of Classification Search .................. 600/483,
`600/486, 50(L504
`See application file for complete search history.
`
`(56)
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`5,005,581 A
`5,704,367 A
`5,899,927 A
`6,083,157 A
`6,605,045 B2
`6,669,632 B2
`
`4/1991 Honeyager
`l/l998 Ishikawa et a1.
`5/1999 Ecker et a1.
`7/2000 Noller
`8/2003 Ohsakiet a1.
`12/2003 Nanba et al.
`
`An apparatus for detecting Vital functions has a pulse wave
`sensor attachable to a body and a control unit. The control unit
`checks if amplitude of pulse wave signals produced from the
`pulse wave sensor varies. The control unit further checks if a
`large change in the amplitude during a systolic phase of a
`pulse wave corresponding to the systolic phase ofthe heart. If
`a first large change in the amplitude during a diastolic phase
`of a pulse wave corresponding to the diastolic phase of the
`heart, it is highly probable that a motion artifact has occurred.
`Therefore, a motion artifact flag is set. Next, it is checked if
`the amplitude in the next diastole is changing by more than
`30%. if it is presumed that the occurrence of cough is highly
`probable, a cough flag is set. if it is neither the motion artifact
`nor the cough, then a yawn flag is set.
`
`26 Claims, 10 Drawing Sheets
`
`
`PULSE WAVE
`
`SENSOR
`
`
`V
`
`
`
`
`
`ACTUATORS
`
`A | R-COND | T | ONER
`
`AlR’PURIFIER
`NAV I GAT ION
`
`AUD I 0
`
`SEATBELT
`
`ETC.
`
`
`APPLE 1010
`
`APPLE 1010
`
`1
`
`

`

`US. Patent
`
`May 15, 2012
`
`Sheet 1 of 10
`
`US 8,177,720 B2
`
`
`
` ACTUATORS
`AIR-CONDITIONER
`AIR-PURIFIER
`NAVIGATION
`AUDIO
`SEATBELT
`
`f—N
`
`
`
`
`
`
`
`
`IOOb
`
`100
`
`100a
`
`2
`
`

`

`US. Patent
`
`May 15, 2012
`
`Sheet 2 of 10
`
`US 8,177,720 B2
`
`FIG. 2A
`SYSTOLE
`-,7:-
`
`23
`;;v»"ff1 ‘rj:~ r::»\7jj~.-=:7 -7~‘§.72i
`
`PULSE WAVE
`
`‘
`
`-
`
`I 'l
`
`" '
`
`l
`
`'
`
`2-
`
`I II
`
`\
`
`II
`
`DIASTOLE
`
`FIG. 23
`
`RESPIRATION '
`WAVEFORM
`
`(A—B)
`
`BL
`
`LL
`
`MOTION ARTIFACT
`‘‘‘‘‘
`
`-.A-
`
`SYSTOLE
`
`
`
`FIG 3A
`
`PULSE WAVE
`
`LL"
`
`FIG. 3B
`
`.....
`DIASTOLE
`
` ‘:7._“
`
`FALLS
`
`RESPIRATION
`
`WAVEFORM
`
`3
`
`

`

`U.S. Patent
`
`May 15
`
`,2012
`
`Sheet 3 of 10
`
`US 8,177,720 B2
`
`2:_ow:
`
`0*.0E
`
`4
`
`

`

`U.S. Patent
`
`May 15, 2012
`
`Sheet 4 of 10
`
`US 8,177,720 B2
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`U.S. Patent
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`May 15, 2012
`
`Sheet50f10
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`US 8,177,720 B2
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`U.S. Patent
`
`US 8,177,720 B2
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`U.S. Patent
`
`May 15, 2012
`
`Sheet70f10
`
`US 8,177,720 B2
`
`mm.9“.
`
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`

`

`US. Patent
`
`May 15, 2012
`
`Sheet 8 of 10
`
`US 8,177,720 B2
`
`FIG. 9
`
`
`
`START
`
`
`
`
`AMPLITUDE
`
`CHANGE IN
`
`PULSE WAVE?
`
`SET MOTION
`ARTIFACT FLAG TI
`
`
` FIRST CHANGE
`IN SYSTOLE?
` 3130
`
`
`
`3120
`YES
`
` AMPLITUDE
`CHANGE IN NEXT
`
`DIASTOLE?
` SET COUGH
`
`
`FLAG SI
`
` SET YAWN FLAG A1
`
`
`
`9
`
`

`

`US. Patent
`
`May 15, 2012
`
`Sheet 9 of 10
`
`US 8,177,720 B2
`
`FIG. 10
`
`RESPIRATION
`WAVEFORM
`
`SET COUGH
`FLAG $2
`
`3240
`
`
`
`10
`
`SET MOTION
`
`DOUBLE
`
`TRIANGULAR
`
`
`
`WAVE?
`
`YES
`
`3220
`
`“0
`
`MORE THAN
`3W1?
`
` $200
`
` N0
`
`ARTIFACT FLAG T2
`
`
`SET YAWN FLAG A2
`
`10
`
`

`

`US. Patent
`
`May 15, 2012
`
`Sheet 10 of 10
`
`US 8,177,720 B2
`
`FIG. 11
`
`
`
`FORM BASE LEVEL
`
`S300
`
`
`
`FLUCTUATION OF
`
`S310
`
`BASE LEVEL?
`
`
`
`SET COUGH
`FLAG S3
`
`PERIODIC
`‘7
`FLUCTUATION.
`
`3340
`
`SET BLOOD VESSEL
`
`
`
`
`
`
`
`
`
`FLUCTUATION AND
`WITHIN PREDETERMINED
`
`MOTION FLAG K1 SINGLE-SHOT
`
`PERIOD?‘
`
`SET MOTION
`ARTIFACT FLAG T3
`
`SET YAWN FLAG A3
`
`FIG. 12
`
`DETERMINE COMPREHENSIVELY
`BODY CONDITION BASED ON FLAGS
`
`
`S400
`
`
`CONTROL ACTUATORS BASED ON
`DETERMINATION RESULT
`
`S410
`
`11
`
`11
`
`

`

`US 8,177,720 B2
`
`1
`APPARATUS FOR DETECTING VITAL
`FUNCTIONS, CONTROL UNIT AND PULSE
`WAVE SENSOR
`
`CROSS REFERENCE TO RELATED
`APPLICATION
`
`This application is based on and incorporates herein by
`reference Japanese Patent Application No. 2006-152354 filed
`on May 31, 2006.
`
`FIELD OF THE INVENTION
`
`This invention relates to a device for detecting Vital func-
`tions, that is, biometric conditions, such as cough and yawn
`by using a pulse wave sensor that is easy to mount.
`
`BACKGROUND OF THE INVENTION
`
`A nasal thermistor, a nasal pressure sensor, a chest-band
`sensor and the like are respiratory system monitors for detect-
`ing breathing (respiration), cough and yawn.
`As for measuring, for example, the cough, various devices
`using a spiro-breathing flow meter (patent document 1), sig-
`nals of the thyroid (patent document 2) and Vibration of a
`catheter (patent document 3). These measuring devices and
`measuring methods are so complicated that the cough and the
`like cannot be easily measured in private homes or vehicles.
`As simpler technologies, it is proposed to use a pattern of
`voice signals detected by a microphone (patent document 4)
`or voice signals and a sound pressure level detected by a
`microphone (patent document 5). The accuracy of detection
`is low due to noise, and it is difficult to specify the source of
`sound when there is a plurality of persons.
`It is also proposed to use a camera image of a nose (patent
`document 6) or variation in a bed load (patent document 7). In
`case of using the image, the image is taken at a particular
`position imposing limitation on the position for taking a mea-
`surement. Besides, a person puts his or her hand to a mouth
`when coughing. Therefore, the hand becomes a blind which
`lowers the accuracy ofdetection. In case ofusing the bed load,
`the motion artifact such as body motion cannot be separated
`from the cough.
`As a method of detecting yawn, further, it is proposed to
`use a camera image or voice (patent document 8). This
`method requires a complicated measuring device. It is also
`proposed to detect respiration conditions by analyzing pulse
`waves (patent documents 9 to 11).
`[Patent document 1] JP-A-8-l73403
`[Patent document 2] JP-A-9-98964
`[Patent document 3] JP-T—l 1-506380 (US. Pat. No. 5,899,
`927)
`[Patent document 4] JP-A-7-376
`[Patent document 5] JP-A-2003-38460
`[Patent document 6] JP-A-8-257015 (US. Pat. No. 5,704,
`367)
`[Patent document 7] JP-A-2003-552
`[Patent document 8] JP-A-2005-l 99078
`[Patent document 9] JP-A-2002-355227 (US. Pat. No.
`6,669,632)
`[Patent document 10] JP-A-2002-78690 (US. Pat. No.
`6,856,829)
`[Patent document 11] JP-A-2002-153432 (US. Pat. No.
`6,856,829)
`
`SUMMARY OF THE INVENTION
`
`The present invention has an object of providing an appa-
`ratus for detecting vital functions such as cough and yawn
`
`2
`
`based on a simple method, a control unit therefor and a device
`for mounting a pulse wave sensor unit.
`(1) According to a first aspect of the invention, it is deter-
`mined that a motion artifact has occurred when the ampli-
`tudeiduring a diastolic phase ofa pulse wave (“on p-diastole
`side” for short)4corresponding to the diastolic phase of the
`heart has exceeded a predetermined lower-limit level that
`corresponds to the lowest blood pressure.
`Through experiments, it was confirmed that the motion
`artifact has occurred if the amplitude on p-diastole side falls
`below the lower-limit level as shown in FIG. 3A.
`
`Namely, the minimum blood pressure (the diastolic blood
`pressure) is maintained by the elasticity ofblood vessels, and
`it does not happen that the amplitude on p-diastole side sud-
`denly becomes lower than the lower-limit level as observed
`based upon the pulse wave signals. If a signal of a pulse wave
`lower than the diastolic blood pressure appears, therefore, it is
`regarded that the motion artifact has occurred. In the diagram
`illustrating the pulse waves, the upper side is expressed to be
`the side of systole and the lower side is expressed to be the
`side of diastole for easy comprehension relative to the blood
`pressure (diagram which is usually called inverted pulse
`waves).
`As the lower-limit level for determining the intensity on
`p-diastole side, for example, an approximated line can be
`employed that is found from a plurality ofpeaks on p-diastole
`side representing the diastolic blood pressure. However, val-
`ues that are increased or decreased by a predetermined per-
`centage may be selected as the lower-limit level.
`(2) According to a second aspect of the invention, a respi-
`ration waveform (respiration curve) that represents the respi-
`ration condition is found from the pulse waves. It is deter-
`mined that a cough has occurred when a double triangular
`wave of an acute angle is detected, in which two peaks of the
`respiration waveforms are consecutively exceeding a prede-
`termined level.
`
`If a cough occurs, a double triangular wave of an acute
`angle lower than a predetermined level (since the thoracic
`pressure has a negative sign, the respiration waveforms in the
`graph are expressed protruding downward) is observed
`within a short period of time (e.g., within 1 to 2 seconds) as
`shown in FIG. 5B due to the motion of muscles specific to
`coughing. Therefore, the above conditions are used for deter-
`mining the coughing. Here, the double triangular wave of an
`acute angle has acute angles that are formed by the lines on
`the outer sides of the right and left peaks.
`In case the amplitude of the respiration waveform has
`increased by more than, for example, 30% beyond the normal
`amplitude, it is probable that a coughing has occurred. There-
`fore, there may be added another determining condition, i.e.,
`ifthe amplitude is greater than a predetermined level. Further,
`the predetermined level (or the predetermined period) used
`for the determination can be set by finding an optimum value
`through experiment (the same holds hereinafter).
`(3) According to a third aspect of the invention, it is deter-
`mined that a cough has occurred when the amplitudegduring
`a systolic phase of a pulse wave (“on p-systole side” for
`short)icorresponding to the systolic phase of the heart has
`exceeded a predetermined level (predetermined level on
`p-systole side) and when the amplitude on p-diastole side
`corresponding to the succeeding diastolic phase of the heart
`has exceeded a predetermined level (predetermined level on
`p-diastole side).
`If a cough has occurred, a peak of the pulse wave signal on
`p-systole side once greatly rises as shown in FIG. 5A and,
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`12
`
`12
`
`

`

`US 8,177,720 B2
`
`3
`immediately thereafter, the peak on p-diastole side greatly
`falls. Therefore, this condition is employed as a condition for
`determining the coughing.
`it is
`(4) According to a fourth aspect of the invention,
`determined that a cough has occurred when the amplitude on
`p-systole side corresponding to the systolic phase of the heart
`has increased by more than a predetermined level (beyond,
`for example, the normal amplitude on p-systole side) without
`causing the waveform of the pulse waves to be varied (dis-
`torted or broken in shape) from the waveform of ordinary
`pulse waves.
`If the couth has occurred as shown in FIG. 5A, the ampli-
`tude on p-systole side rises without causing the pulse waves to
`vary. Therefore, this condition is employed as a condition for
`determining the coughing.
`As a method of determining a case where the waveform of
`the pulse wave varies from the ordinary waveform, there can
`be employed, for example, a method of obtaining a correla-
`tion between the waveforms of pulse waves. For example,
`waveforms of several pulse waves in an ordinary state free of
`motion artifact or coughing are averaged to obtain a repre-
`sentative waveform of pulse waves, which is, then, recorded,
`while a correlation of a waveform of a wavelength or of a
`plurality ofwavelengths is obtained relative to the pulse wave
`that is to be compared. If the correlation is, for example, not
`larger than 0.7, it can be so determined that the waveform of
`the pulse wave has varied. In addition to the correlation, there
`can be employed the analysis of peak-to-peak pitch variation
`of the pulse waves or the analysis of chaos.
`(5) According to a fifth aspect of the invention, it is deter-
`mined that a cough has occurred when a change in the ratio
`(AW2/BW2) of the amplitude (AW2) of the base level of a
`pulse wave/amplitude (BW2) of a pulse wave is within a
`predetermined level (e.g., a change is within 30% of when
`there is no motion artifact) and when the time of change is
`within a predetermined period (e.g.,
`1 to 2 seconds corre-
`sponding to the coughing).
`The probability of coughing is high if the above condition
`is satisfied. Therefore, this condition is employed here as a
`condition for determining the coughing.
`(6) According to a sixth aspect of the invention, it is more
`reliably determined that a coughing has occurred when a
`motion artifact is not detected than when the motion artifact is
`
`detected while determining the occurrence of coughing based
`on at least one cough determining method among the above
`cough determining methods.
`The occurrence of coughing and the intensity of coughing
`can be determined more accurately when a plurality of cough
`determining methods are used in combination than when the
`cough determining method of any one of the above aspects is
`used.
`
`(7) According to a seventh aspect of the invention, it is
`determined that a yawn has occurred when the base level of a
`pulse wave is lowered over a predetermined period corre-
`sponding to the yawning.
`If a yawing has occurred, the base level of pulse waves is
`mildly lowered as shown in FIG. 7A due to the motion of
`muscles specific to the yawning. Therefore, the base level of
`pulse waves remains lowered for a predetermined period
`(e.g., 4 to 12 seconds). Therefore, this condition is employed
`as a condition for determining the yawning.
`As a case where the base level is lowered for a predeter-
`mined period, there can be employed a period in which the
`base level is in a lowered state or a period in which the base
`level is in a state lower than a certain determining value
`(period of the sum of being lowered and elevated).
`
`4
`
`(8) According to an eighth aspect of the invention, it is
`determined that a yawn has occurred when the amplitude of
`pulse waves has become smaller than a predetermined level
`(predetermined level for determining the amplitude of pulse
`waves) within a period in which the base level of pulse waves
`is lower than a predetermined level (predetermined level for
`determining the base level).
`When the base level of pulse waves has increased from the
`lowered state as shown in FIG. 7A, the amplitude of pulse
`waves (whole amplitude in the up-and-down direction)
`decreases due to the motion of muscles specific to the yawn-
`ing. Therefore, this condition is employed as a condition for
`determination to further improve the accuracy of determina-
`tion.
`
`(9) According to a ninth aspect of the invention, it is deter-
`mined that a yawn has occurred when the amplitude on p-sys-
`tole side corresponding to the systolic phase of the heart
`exceeds a predetermined level (predetermined level on p-sys-
`tole side) but the amplitude on p-diastole side corresponding
`to the diastolic phase of the heart does not become smaller
`than a predetermined level (predetermined level on p-diastole
`side).
`If a yawn has occurred, a peak on p-systole side slightly
`increases as shown in FIG. 7A due to the motion of muscles
`
`specific to the yawning. However, a peak ofthe pulse wave on
`the side of the expansion period immediately thereafter does
`not become lower than the normal value (the peak, usually,
`increases slightly). Therefore, this condition is employed as a
`condition for determining the yawning.
`it is
`(10) According to a tenth aspect of the invention,
`determined that a yawn has occurred when the whole ampli-
`tude of pulse waves becomes smaller than a predetermined
`level (predetermined level for determining the whole ampli-
`tude) after the amplitude on p-systole side corresponding to
`the systolic phase of the heart has exceeded a predetermined
`level (predetermined level for determining the amplitude on
`p-systole side) without causing the waveform of pulse waves
`detected by a pulse wave sensor to be varied from the wave-
`form of ordinary pulse waves.
`When a yawn occurs as shown in FIG. 7A, a peak on
`p-systole side slightly increases and, thereafter, the amplitude
`of pulse waves decreases without causing the pulse waves to
`be varied. Therefore, this condition is employed as a condi-
`tion for determining the yawning.
`(11) According to an eleventh aspect of the invention, a
`respiration waveform representing the respiration state is
`found from the pulse waves. It is determined that a yawn has
`occurred when the amplitude of the respiration waveform is
`not smaller than a predetermined level (predetermined angle
`for determining the amplitude) and when a double triangular
`wave of an obtuse angle is detected in which two peaks ofthe
`respiration waveform are consecutively exceeding a prede-
`termined level
`(predetermined level for determining the
`peak).
`If a yawn has occurred as shown in, for example, FIGS. 8A
`to 8C, a double triangular wave of an obtuse angle (of larger
`than a predetermined amplitude) occurs, in many cases, on
`the respiration waveform. Therefore,
`this condition is
`employed here as a condition for determining the yawning.
`Here, the double triangular wave of an obtuse angle stands
`for a double triangular wave in which the angle formed by
`lines on the outer sides of the right and left peaks is an obtuse
`angle.
`(12) According to a twelfth aspect of the invention, it is
`determined that a cough has occurred when a change in the
`ratio (AW2/BW2) ofthe amplitude (AW2) ofthe base level of
`a pulse wave/amplitude (BW2) of a pulse wave is not smaller
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`13
`
`13
`
`

`

`US 8,177,720 B2
`
`5
`than a predetermined level and when the time of change is
`within a predetermined period corresponding to the yawning.
`As shown in FIG. 7, it was clarified that the probability of
`yawning is high when the change of the ratio (AW2/BW2) is
`not smaller than a predetermined level and when the time of
`change is within a predetermined period (e.g., 4 to 12 sec-
`onds) corresponding to the yawning. Therefore, this condi-
`tion is employed here as a condition for determining the
`yawning.
`(13) According to a thirteenth aspect of the invention, it is
`more reliably determined that a yawn has occurred when a
`motion artifact is not detected than when the motion artifact is
`
`detected while determining the occurrence of the yawn based
`on at least one yawn determining method among the above
`yawn determining methods.
`The occurrence of yawning and the intensity of yawning
`can be more accurately determined when a plurality of yawn
`determining methods are used in combination than when the
`yawn determining methods of any one ofthe above aspects is
`used.
`
`(14) A fourteenth aspect of the invention exemplifies pre-
`ferred methods for determining the motion artifact.
`Described below is another example of methods for deter-
`mining the motion artifact.
`It can be determined that the motion artifact has occurred in
`
`case the waveform of the pulse waves has varied from the
`waveform of the ordinary pulse waves.
`That is, in case the motion artifact has occurred, vary of the
`pulse waves is observed as shown in FIG. 3A. If such a change
`is detected, therefore, it can be so determined that the motion
`artifact has occurred. The ordinary pulse waves are pulse
`waves in a calm state where there is no such changes as
`motion artifact, cough or yawn.
`A respiration waveform (respiration curve) that represents
`the respiration state is found from the pulse waves. It is so
`determined that the motion artifact has occurred if the ampli-
`tude of the respiration waveform has changed by more than a
`predetermined level and if the waveform of a pulse wave has
`varied from the waveform of the ordinary pulse waves.
`That is, in case the motion artifact has occurred, a change in
`the amplitude of the respiration waveform is observed as
`shown in FIG. 3B in addition to the vary ofthe waveforms. In
`case such a change is detected, it may be so determined that
`the motion artifact has occurred.
`
`Here, as described in the above patent document 9, a first
`variation signal representing a varying state from the pulse
`wave is found, a second variation signal representing a vary-
`ing state of the first variation signal is found, and the respira-
`tion waveform (respiration curve) is found based on a differ-
`ence between the first variation signal and the second
`variation signal.
`As the first variation signal as shown in FIG. 2, there can be
`employed a first envelope that connects the peaks of wave-
`forms of signals of pulse waves or a first amplitude ratio line
`that connects the points dividing the amplitudes of wave-
`forms of signals of pulse waves by a predetermined ratio. As
`the second variation signal, further, there can be employed a
`second envelope that connects the peaks of waveforms of the
`first variation signals or a second amplitude ratio line that
`connects the points dividing the amplitudes of waveforms of
`the first variation signals by a predetermined ratio.
`It can be determined that a motion artifact has occurred
`
`when a ratio (AW2/BW2) ofthe amplitude (AW2) ofthe base
`level of a pulse wave/amplitude (BW2) of a pulse wave has
`changed by more than a predetermined level, the change
`being of a nature of a single-shot and when the time of change
`
`6
`is outside a predetermined period (shorter than, for example,
`4 seconds or longer than, for example 12 seconds) that cor-
`responds to the yawning.
`Namely, as will be described later, when the ratio (AW2/
`BW2) of the amplitude (AW2) of the base level of a pulse
`wave/amplitude (BW2) of a pulse wave has changed by more
`than a predetermined level, it is probable that a yawning is
`occurring. However, when the change is of a nature of a
`single-shot and the period of change is different from the
`period of the case of yawning, it was clarified through experi-
`ments that the probability of motion artifact is high.
`Whether the change is of a nature of a single-shot can be
`determined based on if the change has occurred only once
`within a preset period (e.g., 20 seconds).
`Referring to FIG. 7A, further, the amplitude (AW2) of the
`base level of the pulse waves stands for a width of deviation
`from the center of the base level while the amplitude (BW2)
`of the pulse waves represents the whole width in the up-and-
`down direction of the pulse waves. As the amplitude of the
`base level ofthe pulse waves, however, there can be employed
`the hole amplitude in the up-and-down direction of the base
`level.
`
`When it is determined by a plurality of motion artifact-
`determining method that a motion artifact has occurred, it can
`be more reliably determined that the motion artifact has
`occurred than when it is not.
`
`the accuracy of determination can be more
`is,
`That
`improved when a plurality of motion artifact determinations
`are combined together than when each of the above motion
`artifact determinations is used.
`
`As described above in detail, the apparatus for detecting
`the conditions of a body of the second to fourteenth aspects
`detects the cough or yawn by utilizing signals obtained
`through a pulse wave sensor, i.e., easily detects the cough or
`yawn (or deep respiration) in private homes or vehicle com-
`partments based on a method simpler than the conventional
`methods.
`
`In the above aspects, the pulse waves canbe measured from
`an arm or a finger in addition to the face by using the pulse
`wave sensor offering a distinguished effect of cleanly taking
`a monitoring at a portion kept away from the cough, spit or
`phlegm that could become a cause of infectious disease to the
`respiratory systems.
`On account of each time of cough or yawn can be detected,
`it is allowed to find the number of coughs and yawns (to
`render a quantitative evaluation). Based on the number
`theory, therefore, it is also allowed to diagnose the degree of
`symptom such diseases as chronic bronchitis or whooping
`cough, or to detect the sign of sleepiness.
`(15) According to a fifteenth aspect of the invention, when
`the occurrence of cough or yawn is determined by the above
`various methods for determining the cough or yawn (inclu-
`sive of definite cough determining method definite yawn
`determining method), various actuators are controlled such as
`adjusting the temperature and blow rate of an air conditioner,
`offering a guide by the navigation system or varying the state
`of the seat and the seat belt based upon the results of deter-
`mination, for example, upon the symptoms so as to relax the
`coughing or to promote the recovery from the sleepiness.
`That is, an alarm is produced as required, or the environ-
`ment is controlled being linked to the air conditioner. Further,
`the disease is determined based on the determined results of
`
`coughing and yawning. If it is a cold, the temperature and
`humidity are suitably set. If it is an allergic rhinitis, the air in
`the compartment may be replaced with the fresh external air
`or an auxiliary filter may be operated. Further, the data of the
`
`5
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`10
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`15
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`20
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`25
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`30
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`35
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`40
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`45
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`50
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`55
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`60
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`65
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`14
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`14
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`

`

`US 8,177,720 B2
`
`7
`determined results may be stored to be used for controlling
`the health and for the diagnosis by a doctor.
`(1 6) In a sixteenth aspect ofthe invention, further, ifa pulse
`wave sensor is of an optical type, a buffer member is arranged
`between the pulse wave sensor and the skin so that the optical
`device of the skin side does not come in contact with the skin
`
`or pushes the skin with a pressure which is not larger than a
`predetermined level.
`This restricts the pulse wave sensor from pushing the skin
`with an excess of pressure, and the blood circulation is not
`restricted. Therefore, the measurement can be taken accu-
`rately.
`(17) According to a seventeenth aspect of the invention, a
`sponge having a rugged pattern on the skin side may be used
`as the preferred buffer member.
`(18) In an eighteenth aspect of the invention, if the pulse
`wave sensor is of the optical type, an elastic member may be
`arranged on the pulse wave sensor on the side opposite to the
`skin for mounting the pulse wave sensor on the surface of the
`body, so that the optical device pushes the skin with a pressure
`which is not larger than a predetermined level.
`This prevents the pulse wave sensor from pushing the skin
`with an excess ofpressure. Therefore, an excess of load is not
`given to the skin, the waveforms of pulses are not distorted,
`and the pulse waves can be accurately measured.
`(1 9) A nineteenth aspect of the invention uses a band (for
`example, a rubber material or an expansible bandage) as a
`preferred elastic member for fixing the pulse wave sensor to
`the body.
`(20) A twentieth aspect ofthe invention uses a member (for
`example, a spring or the like) as a preferred elastic member
`for fixing the pulse wave sensor to the body.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`The above and other objects, features and advantages ofthe
`present invention will become more apparent from the fol-
`lowing detailed description made with reference to the
`accompanying drawings. In the drawings:
`FIG. 1A is a schematic diagram illustrating an apparatus
`for detecting the conditions of a body and a mounting device
`therefor according to an embodiment, and FIG. 1B is an
`enlarged schematic view illustrating a pulse wave sensor used
`in the embodiment;
`FIG. 2A is a graph illustrating a waveform of pulse waves,
`and FIG. 2B is a graph illustrating a respiration waveform;
`FIG. 3A is a graph illustrating a waveform of pulse waves
`of when there is a motion artifact, and FIG. 3B is a graph
`illustrating a respiration waveform of when there is a motion
`artifact;
`FIG. 4A is a graph illustrating a waveform of pulse waves
`of when there is a strong motion artifact, FIG. 4B is a graph
`illustrating a respiration waveform of when there is a strong
`motion artifact, FIG. 4C is a graph illustrating a waveform of
`pulse waves of when there is a motion artifact of an interme-
`diate degree, FIG. 4D is a graph illustrating a respiration
`waveform of when there is a motion artifact of an intermedi-
`
`ate degree, FIG. 4E is a graph illustrating a waveform ofpulse
`waves of when there is a weak motion artifact, and FIG. 4F is
`a graph illustrating a respiration waveform of when there is a
`weak motion artifact;
`FIG. 5A is a graph illustrating a waveform of pulse waves
`of when a cough has occurred, and FIG. 5B is a graph illus-
`trating a respiration waveform ofwhen a cough has occurred;
`FIG. 6A is a graph illustrating a waveform of pulse waves
`of when a strong cough has occurred, FIG. 6B is a graph
`illustrating a respiration waveform of when a strong cough
`
`8
`has occurred, FIG. 6C is a graph illustrating a waveform of
`pulse waves of when a cough of an intermediate degree has
`occurred, FIG. 6D is a graph illustrating a respiration wave-
`form ofwhen a cough of an intermediate degree has occurred,
`FIG. 6E is a graph illustrating a waveform of pulse waves of
`when a weak cough has occurred, and FIG. 6F is a graph
`illustrating a respiration waveform ofwhen a weak cough has
`occurred;
`FIG. 7A is a graph illustrating a waveform of pulse waves
`of when a yawn has occurred, and FIG. 7B is a graph illus-
`trating a respiration waveform of when a yawn has occurred;
`FIG. 8A is a graph illustrating a waveform of pulse waves
`of when a strong yawn has occurred, FIG. 8B is a graph
`illustrating a respiration waveform ofwhen a strong yawn has
`occurred, FIG. 8C is a graph illustrating a waveform of pulse
`waves of when a yawn of an intermediate degree has
`occurred, FIG. 8D is a graph illustrating a respiration wave-
`form of when a yawn of an intermediate degree has occurred,
`FIG. SE is a graph illustrating a waveform of pulse waves of
`when a weak yawn has occurred, and FIG. 8F is a graph
`illustrating a respiration waveform of when a weak yawn has
`occurred;
`FIG. 9 is a flowchart illustrating processing for setting flags
`T1, 81 and A1;
`FIG. 10 is a flowchart illustrating processing for setting
`flags T2, 82 and A2;
`FIG. 11 is a flowchart illustrating processing for setting
`flags T3, S3 and A3; and
`FIG. 12 is a flowchart illustrating control processing based
`on a comprehensive determination of the motion artifact,
`coughing and yawning.
`
`DESCRIPTION OF THE PREFERRED
`EMBODIMENTS
`
`First, a biometric detection apparatus for detecting condi-
`tions of a body is described with reference to one embodiment
`shown in FIGS. 1A and 1B. The apparatus detects vital func-
`tions such as cough or yawn by using a pulse wave sensor 1.
`This sensor 1 is attached to a portion of a human body 100
`such as a finger, a palm or a wrist, where motion is small. The
`apparatus further uses a control unit 3, which drives the pulse
`wave sensor 1 and processes the outputs from the pulse wave
`sensor 1.
`
`Here, the pulse wave sensor 1 is an optical sensor of the
`reflection type (opto-capacitive pulse wave sensor) compris-
`ing a light-emitting element (e.g., light-emitting diode: green
`LED) 5, a light-receiving element (e.g., photodiode: PD) 7,
`and a transparent lens 9 which permits light to pass through
`and also efliciently receives light.
`The pulse wave sensor 1 has a ring-like buffer member
`(e.g., a sponge having a rugged end) 11 that serves as a spacer
`sur