OS2-4-12
LIFE2012 2012 ೥ 11 ݄ 2 ೔–4 ೔ Ѫ஌ (໊‫ݹ‬԰େֶ)ମಋԻηϯαΛ༻ཱ͍ͨࣗ‫຺ܕ‬ഥ਺‫ݕ‬ग़γεςϜ

Autonomous pulse measurement system using body-conducted sound sensor˓‫ٱ‬อ੟߂ʢࢁ‫ޱ‬େֶʣ ాத‫װ‬໵ʢࢁ‫ޱ‬େֶʣ एࠤ༟࣏ʢࢁ‫ޱ‬େֶʣதౡᠳଠʢࢁ‫ޱ‬େֶʣ ߐ‫࢙ݪ‬࿕ʢӉ෦޻‫ߴۀ‬౳ઐ໳ֶߍʣ
Takahiro Kubo, Yamaguchi Universty
Kanya Tanaha, Yamaguchi Universty
Yuji Wakasa, Yamaguchi Universty
Syota Nakashima, Yamaguchi Universty
Fumiaki Ehara, Ube National College of Technology
Abstract: In late years, the lonely death of elderly people living alone becomes the big social problem. Therefore, adevice to monitor the health condition of elderly people living alone is necessary. In this paper, we construct a system,
which notiﬁes the pulse rate and physical information to remote place. Firstly, we produce a body conduction soundsensor using an electret condenser microphone is covered by Polyurethane elastomer, which simpliﬁed measurementof artery sounds. Secondly, we construct a subsystem, which calculates the pulse rate by measuring the artery soundof the wrist. After denoising, the pulse rate date is derived using an autocorrelation method, which is a method tomeasure a period of the signal. The artery sound measurement device is comprised of a microcomputer called mbed tomeasurement and autocorrelation, and XBee to transmit pulse rate. We have conﬁrmed the usefulness of the systemby wearing the actual actually, to derive the pulse at rest and during walking.
Key Words: Wellbeing Science, Welfare Engineering, Body Conducted Sound Sensor,
1.

͸͡Ίʹ

ۙ೥, ߴྸࣾձͷਐߦʹ൐͍ಠ‫ऀྸߴډ‬ͷ਺͕૿Ճͯ͠
͍Δ. ߴྸࣾձനॻʹΑΔͱฏ੒ 22 ೥౓ʹ͓͚Δಠ‫ྸߴډ‬ऀ਺͸໿ 480 ສਓͰ͋Δ (1) . ͦΕʹ൐͍, ಠ‫ऀྸߴډ‬ͷ‫ݽ‬ಠࢮͳͲ͕ࣾձ໰୊ʹͳ͍ͬͯΔ. ຊ‫Ͱڀݚ‬͸, ͜ͷΑ͏ͳ໰୊Λղܾ͢ΔͨΊʹମಋԻηϯαΛ༻຺͍ͯഥΛ‫ܭ‬ଌ͠ಠ‫ऀྸߴډ‬ͷ݈߁ঢ়ଶΛਵ࣌ϞχλϦϯά͢Δ͜ͱͰ҆൱֬ೝΛߦ͏͜ͱΛ໨తͱ͍ͯ͠Δ. ମಋԻͱ͸ମͷ಺֎ͰҾ͖‫͜͞ى‬Εͨৼಈ͕ମ಺΍ମදΛ఻ൖ͢ΔԻͷ͜ͱͰ͋Γ, ຊ‫Ͱڀݚ‬͸खटͷᒷࠎಈ຺ԻΛ࠾औ͢Δ͜ͱͰ຺ഥΛಋग़͍ͯ͠Δ. ‫ݱ‬ঢ়Ͱ͸ମಈ࣌ʹ͓͍ͯ, ϊΠζʹΑΔ‫ޡ‬͕ܹࠩ͘͠ਖ਼֬ͳ຺ഥͷಋग़͕ࠔ೉Ͱ͋ͬͨ. ໰୊ͷղܾʹ͋ͨΓ, ηϯα͓Αͼ຺ഥ‫ܭ‬ଌͷΞϧΰϦζϜͷվྑΛߦ͍γεςϜͷ༗༻ੑΛ֬ೝͨ͠.
2.

຺ഥ਺Λ‫͠ࢉܭ‬, ແઢ‫ػ‬ͷ੍‫ޚ‬΋ߦ͍ͬͯΔ. ແઢ‫ػ‬͸DigiInternational ࣾͷ XBee Λ༻͍͍ͯΔ. XBee ͱ͸খ‫ܕ‬ͷ୹‫༻཭ڑ‬ແઢ‫͋Ͱػ‬Γ࢖༻प೾਺ଳ͸ 24GHz, ௿ফඅిྗ, ௨৴‫཭ڑ‬͸਺ 10m ͱ͍ͬͨಛ௃Λ΋ͭ. ͜ͷແઢ‫ػ‬Λ༻͍ͯಋग़͞Ε຺ͨഥ਺Λ PC ΁ૹ৴͍ͯ͠Δ.

Fig. 1 Autonomous pulse measurement systemཱࣗ‫຺ܕ‬ഥ‫ݕ਺ܭ‬ग़૷ஔຊ૷ஔ͸, ମಋԻηϯα, ຺ഥ਺ಋग़෦, ͓Αͼແઢ‫͔ػ‬Βߏ੒͞Ε͍ͯΔ (Fig1).
2-1 ମಋԻηϯαମಋԻηϯα͸ϓϦϞࣾͷΤϨΫτϨοτίϯσϯαϚΠΫϩϗϯʢҎԼ ECM ͱ͢ΔʣΛ༻͍ͯखटͷᒷࠎಈ຺ԻΛ࠾औ͍ͯ͠Δ. ECM ͸௿प೾਺ଳҬʹ͓͍ͯߴ‫౓ײ‬ಛੑͰ͋Γ, ۭ‫ؾ‬ͷඍগͳѹྗมԽͳͲ௿प೾ଳҬ͔ΒՄௌଳҬ·Ͱ‫ݕ‬ग़Ͱ͖ΔσόΠεͰ͋Δ. ECM ͸ΞΫϦϧथࢷ͓ΑͼԘԽϏχϧथࢷͰߏ੒͞Εͨέʔεʹ‫ݻ‬ఆ͞Ε͓ͯΓ, ͦͷ಺෦͸ϙϦ΢ϨλϯΤϥετϚͰॆర͞Ε͍ͯΔ. ͜ͷ೪ணੑ, ࠶ണ཭ੑͷ͋ΔॆరࡎʹΑΓ, ମಈ࣌ͷຎࡲੑࡶԻɾ઀৮ੑࡶԻ͓Αͼ‫ײ‬Ի໘ͷ‫ؾ‬ಋ֎෦ࡶԻͷআ‫ڈ‬ͷޮՌ͕͋Δ (2) (Fig2).
2-2 ຺ഥ਺ಋग़෦͓Αͼૹ৴‫ػ‬ຊ૷ஔͰ͸, ຺ഥ਺ಋग़ʹ NXP ࣾͷ mbed Λ༻͍ͯ
͍Δ. mbed ͱ͸ 32bit ͷߴ଎ϓϩτλΠϓϚΠίϯͰ͋Γ, ଞͷ 8bit ϚΠίϯͱൺ΂ߴ͍ॲཧೳྗΛ࣋ͪ, ಉ࣌ʹϝϞϦ༰ྔ͕େ͖͍ಛ௃͕͋Δ. ͜ͷ૷ஔΛ༻͍ͯ,Fig. 2 Body-conducted sound sensor

3.

຺ഥ਺ಋग़աఔ຺ഥ਺ಋग़෦Ͱ͸, ମಋԻηϯαʹΑͬͯ࠾औ͞Εͨಈ຺Իσʔλʹରͯ͠ϊΠζͷআ‫ڈ‬Λߦ͍, ͦͷ‫ݾࣗޙ‬૬ؔʹΑͬͯಈ຺Իͷप‫ظ‬Λ‫ٻ‬ΊΔ. ͞Βʹ, ‫ٻ‬Ίͨप‫͔ظ‬Β຺ഥΛಋग़͍ͯ͠Δ.
3-1 ϊΠζͷআ‫ڈ‬ຊ૷ஔͰ͸, ଌఆ͞Εͨಈ຺Իʹରͯ͠ϝσΟΞϯϑΟϧλॲཧΛߦ͏͜ͱͰϊΠζͷআ‫ڈ‬Λߦ͍, ຺ഥಋग़ͷਫ਼−1−౓Λ্͍͛ͯΔ. ϝσΟΞϯϑΟϧλͱ͸, ͋Δσʔλ఺ʹରͯͦ͠ͷपғͷྖҬͷσʔλ஋Λιʔτͦ͠ͷதԝ஋ΛͱΔͱ͍ͬͨ΋ͷͰ, 1 ఺ͷΈඈΜͩ஋ͳͲͷϊΠζ͕‫·ؚ‬Εͨσʔλ‫ʹྻܥ‬ରͯ͠༗ޮͰ͋Γ, ը૾ॲཧͷ෼໺ͳͲʹ޿͘Ԡ༻͞Ε͍ͯΔ.
3-2 ࣗ‫ݾ‬૬ؔؔ਺

3-1 ͷΑ͏ʹϊΠζআ‫ڈ‬Λߦͬͨσʔλ‫ʹྻܥ‬ର͠, ࣗ‫ݾ‬૬ؔΛߦ͏͜ͱͰͦͷσʔλ‫͕ͭ࣋ྻܥ‬प‫ظ‬ੑΛ‫ٻ‬ΊΔ͜ͱ͕Ͱ͖Δ. ࣗ‫ݾ‬૬ؔͱ͸৴߸ॲཧʹ͓͍ͯ, ͦͷ৴߸͕࣋ͭ‫܁‬Γฦ͠ύλʔϯΛ୳͢ͷʹ༗༻Ͱ͋Γ, ϊΠζʹຒ΋Εͨप‫ظ‬৴߸ͷଘࡏͷ൑ఆͳͲ, ෯޿͍෼໺ʹԠ༻͞Ε
͍ͯΔ. ࣗ‫ݾ‬૬ؔؔ਺Λࣜ (1) ʹࣔ͢. ࣜ (1) ͔ΒΘ͔ΔΑ͏ʹ, ৴߸͕ͦΕࣗ਎ͷҐ૬ΛͣΒͨ͠৴߸ͱͲΕ͚ͩΑ͘੔߹͢Δ͔ΛଌΔई౓Ͱ͋Γ, ࣌ؒγϑτͷେ͖͞ͷؔ਺ͱͯ͠ද͞ΕΔ. ͜ͷ͜ͱ͔Β, ຊ૷ஔͰ͸ಘΒΕͨಈ຺Իʹରࣗ͠‫ݾ‬૬ؔΛͱΓ, प‫ظ‬Λ‫ٻ‬ΊΔ͜ͱͰ຺ഥ਺Λಋग़͢Δ.

Fig. 4 Aftre denoiseing measured artery sounds(at rest)

Fig. 5 Autocorrelation result
NR(j) =1 ∑v(i) · v(i + j)
N i=1

Table 1 Veriﬁcation of the system that was prepared.

(j = 0, 1, 2, · · ·) (1)4. ࣮‫ݧ‬4-1 ࣮‫ํݧ‬๏

1
2
3
4
5
67
8
910ຊ૷ஔͷ༗༻ੑΛ֬ೝ͢ΔͨΊʹ, ҆੩࣌ͷ຺ഥΛ 10 ճͣͭଌఆ͠ɺ‫ͨ͠ূݕ‬. ඃ‫ऀݧ‬͸ 20 ୅உੑ, αϯϓϦϯάप‫ظ‬͸ 5.0[ms] Ͱ͋Γ‫ܭ‬ଌ࣌ؒ͸ 10[s] Ͱ͋Δ. ಋग़຺ͨ͠ഥ਺ͷൺֱ༻ͱͯ͠, ಉ࣌ࠁʹ 60[s] ؒͷᒷࠎಈ຺ԻΛ࠾औͨ͠. ͜ͷಈ຺Իσʔλ͔Β຺ഥΛ਺͑Δ͜ͱͰ຺ഥ਺͕ಘΒΕΔ. ҆੩࣌ʹମಋԻηϯαʹΑͬͯ‫ܭ‬ଌ͞ΕͨσʔλΛ Fig3 ʹ, ϊΠζ͓Αͼग़ྗ೾‫ܗ‬ͷ௚ྲྀ੒෼Λআ‫ͨ͠ڈ‬΋ͷΛ Fig4 ʹ, ͞Βʹ҆੩࣌ͷࣗ‫ݾ‬૬ؔ݁Ռ͓Αͼप‫ظ‬Λ
Fig5 ʹࣔ͢.
4-2 ࣮‫݁ݧ‬Ռ҆੩࣌ͷ Fig3,Fig4 ͓Αͼ Fig5 ͔ΒΘ͔ΔΑ͏ʹ, ϊΠζͷআ‫͔ڈ‬Βࣗ‫ݾ‬૬ؔʹΑͬͯͷप‫ظ‬ಋग़·Ͱ໰୊ͳ͘ॲཧͰ͖ͨ͜ͱ͕Θ͔Δ. ͜ͷ৔߹प‫ ͕ظ‬0.69[s] Ͱ͋ΔͷͰ຺ഥ͸ 87[bpm] Ͱ͋Δ. Table 1 ʹ͸, ҆੩࣌ͷ຺ഥಋग़݁Ռͱͦͷൺֱ༻ͷͨΊͷ຺ഥΛද͍ͯ͠Δ. ݁Ռ, ͢΂ͯͷࢼߦʹ͓͍ͯ, ൺֱ༻σʔλͱൺ΂, ΄΅ಉ౳ͷ݁Ռ͕ಘΒΕͨ͜ͱ͕Θ͔Δ. ͜ͷ͜ͱ͔Β, ମಋԻηϯαΛ༻͍ͯࣗಈͰ຺ഥଌఆΛߦ͏͜ͱ͕Ͱ͖, ຊ૷ஔͷ༗༻ੑΛ֬ೝͰ͖ͨ. ͳ͓าߦ࣌ʹ͓͚Δຊ૷ஔͰͷ‫ܭ‬ଌσʔλΛFig6 ʹࣔ͢. ͜ͷΑ͏ʹ, ‫ͨݟ‬໨Ͱ͸຺ഥͷ৴߸͕Θ͔Βͳ͍৔߹ʹ΋, ͦͷ೾‫ܗ‬ͷࣗ‫ݾ‬૬ؔΛͱΔ͜ͱͰप‫͕ظ‬ಋग़Ͱ͖ͨ (Fig5).

PulseRate1[bpm](Using theprepared system)
80
85
87
85
79
81
78
83
77
77

PulseRate2[bpm](Derived by arterialsound data)
82
85
86
84
81
85
81
80
78
79

Fig. 6 Measured artery sounds(at walking)

5.

͓ΘΓʹ

ຊ‫Ͱڀݚ‬͸, ࡞੡ͨ͠૷ஔΛ࣮ࡍʹ૷ண͠, ຺ഥ਺Λ‫ݕ‬ग़͢Δ͜ͱͰ༗༻ੑͷ֬ೝΛ͓͜ͳͬͨ. ݁Ռ, ҆੩࣌Ͱ͸େ͖ͳ‫ࠩޡ‬Λग़͢͜ͱͳ͘ਖ਼֬ͳ຺ഥ਺Λಋग़͢Δ͜ͱ͕
Ͱ͖ͨ. ·ͨ, าߦ࣌ʹ͓͍ͯ΋प‫ظ‬Λಋग़Ͱ͖, ຺ഥ਺ΛׂΓग़͢͜ͱ͕Ͱ͖ͨ. Ҏ্ͷ͜ͱ͔Β, ମಋԻηϯαΛ༻ཱ͍ͨࣗ‫຺ܕ‬ഥ਺‫ݕ‬ग़γεςϜΛߏஙͨ͠ͱ͍͑Δ.
ࢀߟจ‫ݙ‬(1) ಺ֳ෎, ɹߴྸऀനॻ, 2011
(2) Fumiaki Ehara, Toshiaki Tsuruda and Kanya
Tanaka, Development of a Heart Rate Measurement
Method Using Body Conduction Sound Sensor, Applied Mechanics and Materials, vol. 103, pp.616621, 2012.

Fig. 3 Measured artery sounds(at rest)−2−