實現非接觸主動式電極以量測心律之研究
Study of Implementing Non-contact Active
Electrodes to Measure the Heart Rate
Adviser: Huang Ji-Jer
Presenter:Chou Hou-Yu
Date:2015/04/29
1
OUTLINE
1.
Introduction
1.
2.
2.
3.
Brief introduction
ECG background and principles
Paper Review
Materials and Methods
1.
2.
3.
4.
5.
6.
7.
8.
Application
Analog circuits
Driven-right-leg
Signal processing
Digital Circuits
GUI
HRV
Android
2
OUTLINE
4.
Experiments
1.
2.
3.
4.
5.
Results and Discussion
1.
6.
Analog circuit experiment
Each electrode effect of cloth thickness
Each electrode effect of electrode area
ECG simulation experiment
Analog circuit analysis and measurement
Conclusions and Future Work
3
1. Introduction
• 2013 statistical results on causes of death in Taiwan
順
位
1
2
合
ICD-10
國際死因
分類號碼
計
死亡
死 亡 原 因
人數
A00-Y98
所有死亡原因
C00-C97
惡性腫瘤
I01-I02.0, I05-I09,
心臟疾病（高血壓性疾病除外）
I20-I25, I27, I30-I52
每十萬人口
標準化
死亡率
死亡率
死亡
百分比
%
154,374
661.3
435.3
100.0
44,791
191.9
130.4
29.0
17,694
75.8
47.7
11.5
11,313
48.5
30.3
7.3
3
I60-I69
腦血管疾病
4
E10-E14
糖尿病
9,438
40.4
25.8
6.1
5
J12-J18
肺炎
9,042
38.7
22.5
5.9
6,619
28.4
22.4
4.3
6
V01-X59, Y85-Y86 事故傷害
7
J40-J47
慢性下呼吸道疾病
5,959
25.5
14.9
3.9
8
I10-I15
高血壓性疾病
5,033
21.6
12.9
3.3
9
K70, K73-K74
慢性肝病及肝硬化
4,843
20.7
14.8
3.1
4,489
19.2
11.9
2.9
35,153
150.6
101.8
22.8
10
N00-N07, N17-N19,
腎炎、腎病症候群及腎病變
N25-N27
其他
衛生福利部 http://www.mohw.gov.tw/cht/Ministry/DM2_P.aspx?f_list_no=7&fod_list_no=4558&doc_no=45347 103/10/13
4
1. Introduction

Demographic analysis
表一、戶籍登記現住人口數按年齡分
年齡結構百分比 (％)
戶籍人口登記數
年底別
人數
總增加
率(‰)
自然增 社會增
加率(‰) 加率(‰)
0-14歲
性比例 扶養比
(女=100)
(％)
15-64歲 65歲以上
扶幼比 扶老比
老化
指數
(％)
民國93年底
民國94年底
民國95年底
民國96年底
民國97年底
民國98年底
22,689,122
22,770,383
22,876,527
22,958,360
23,037,031
23,119,772
3.73
3.58
4.65
3.57
3.42
3.59
3.59
2.92
3.01
2.76
2.40
2.07
0.14
0.65
1.64
0.81
1.02
1.52
19.34
18.70
18.12
17.56
16.95
16.34
71.19
71.56
71.88
72.24
72.62
73.03
9.48
9.74
10.00
10.21
10.43
10.63
103.53
103.16
102.72
102.28
101.89
101.34
40.48
39.74
39.12
38.43
37.70
36.93
27.16
26.14
25.21
24.30
23.34
22.38
13.31
13.60
13.91
14.13
14.36
14.56
49.02
52.05
55.17
58.13
61.51
65.05
民國99年底
民國100年底
民國101年底
民國102年底
民國103年底
23,162,123
23,224,912
23,315,822
23,373,517
23,433,753
1.83
2.71
3.91
2.47
2.57
0.91
1.88
3.23
1.85
1.98
0.92
0.82
0.67
0.62
0.59
15.65
15.08
14.63
14.32
13.99
73.61
74.04
74.22
74.15
74.03
10.74
10.89
11.15
11.53
11.99
100.94
100.57
100.26
99.96
99.68
35.85
35.07
34.74
34.85
35.08
21.26
20.37
19.72
19.31
18.89
14.59
14.70
15.03
15.55
16.19
68.64
72.20
76.21
80.51
85.70
較102年底
增減率(％)
0.26
②0.10
②0.13
②-0.03
①-0.33 ①-0.12
①0.46
①-0.28 ①0.23 ①-0.42 ①0.65 ①5.19
資料來源：本部戶政司。
說 明 ：1.自 然 增 加 率=(出 生 人 數 － 死 亡 人 數)÷年 中 人 口 數×1,000。
2.社 會 增 加 率=(遷 入 人 口 數 － 遷 出 人 口 數)÷年 中 人 口 數×1,000。
3.總 增 加 率=自 然 增 加 率+社 會 增 加 率。
4.性 比 例 =(男 性 人 口 數/女 性 人 口 數)*100。
5.扶 養 比 =(0-14歲 人 口 +65歲 以 上 人 口)/(15-64歲 人 口 )*100。
6.扶 幼 比 =(0-14歲 人 口 )/(15-64歲 人 口)*100。
7.扶 老 比 =(65歲 以 上 人 口)/(15-64歲 人 口 )*100。
8.老 化 指 數=(65歲 以 上 人 口)/(0-14歲 人 口 )*100。
備
註：①係指增減數或增減百分點。
②係指增減千分點。
內政部統計處 http://www.moi.gov.tw/stat/news_content.aspx?sn=9148 104/4/1
5
1. Introduction
• ECG background and principles
– ECG records the heart in nerve conduction arising from
potential changes graphics
6
1. Introduction

Ag-AgCl
– The middle layer of the skin and the electrodes add gum
containing Cl−
AgCl  e 
Ag  Cl 
Ag   Cl 
7
1. Introduction
ECG:
• Advantages:
Better signals
• Disadvantages:
1. Skin irritations
2. Specific preparation
before measurements
3. Limitations related to
the connecting cables
http://140.134.32.60:83/news/test/biotech/bei/bei.html
102/12/9
8
1. Introduction
Capacitive ECG :
• Advantages:
1. Does not need to contact
skin
2. Make continuous
monitor for long time
3. Application : An office
chair, a bed, a toilet seat ,
automobile
• Disadvantages:
1. Still suffer from strong
artifacts
9
2.Paper Review
Number
Author
Year
Title
①
A.Aleksandrowicz,
S. Leonhardt
2007
Wireless and Non-contact
ECG Measurement System –
the “Aachen SmartChair”
②
S. M. Lee, K. S.
Sim, K. K. Kim, Y.
G. Lim, and K. S.
Park
2010
Thin and flexible active
electrodes with shield for
capacitive electrocardiogram
measurement
③
E. M. Fong and W. 2013
Y. Chung
Mobile Cloud-ComputingBased Healthcare Service by
Noncontact ECG Monitoring
10
2.Paper Review

①
– Comparison of the ECG signals with different a cotton
wool shirt thicknesses
11
2.Paper Review

②
– Effect of cloth thickness(Cotton cloths, electrode were
set to 45 cm²
C : The capacitance
A : The area of overlap of the two plates
εr : Dielectric constant( εr = 1 ,almost air)
ε0 : The electric constant (ε0 ≈ 8.854×10−12 F m–1)
12
2.Paper Review

②
– Effect of electrode area((Cotton cloths,thickness 2050 µm²)
13
2.Paper Review

ECG measurements
14
2.Paper Review

System Design and Implementation
15
2.Paper Review

The comparison between the proposed non-contact
electrodes ECG and standard ECG measurements
(a) ECG signals measured with standard ECG measurement; (b) ECG
signal obtained using non-contact ECG measurement
16
2.Paper Review

The mobile interface
17
3.Materials and Methods

Analog circuits
–
ECG block diagram of the measurement circuit
18
3.Materials and Methods

Capacitive coupling
electrode
– To capture the weak charge
with the capacitive coupling
electrode must place high
impedance and low noise
opamp,the induced charge via
the resistor (𝑅𝐵) ,converted
into a voltage signal output
19
3.Materials and Methods

Analog circuits
– The equivalent circuit

Explanation of terms
—𝐶𝑔:The stray capacitance
between the human and the
ground
—𝐶𝑚:The stray capacitance
between the instrument and
the ground
—Cs: The shielding plate
stray capacitance
—Rsk:Skin impedance
—Rc,CC: Active electrode
impedance
—Rin,Cin:OP impedance
20
3.Materials and Methods
2
1
1
) //
//( Rin //
)
sCm sCs
sCin
Vo  Vs
2
1
2
1
1
//{Rsk  ( Rc //
)  [( Rb 
) //
//( Rin //
)]}
sCg
sCc
sCm sCs
sCin
2
1
2
1
[
// Rsk  ( Rc //
)] //( Rb 
) //( Rin //
)
sCg
sCc
sCm
sCin
 AsVo
1
2
1
2
1

//{[ Rsk  ( Rc //
)] //( Rb 
) //( Rin //
)}
sCs sCg
sCc
sCm
sCin
( Rb 
21
3.Materials and Methods
Cg
Óscas Casas ,2007 [1]
Ccl Cm
20
pF
Tobias Wartzek , 2011 [2]
200
pF
21p
F
Ko Keun Kim and Kwang Suk Park , 2008
[3]
200
pF
33
pF
Emad Alnasser , 2014 [4]
300
Pf
Ko Keun Kim , 2005 [5]
Seung Min Lee, 2010 [6]
Csh
Cin Rb
Rin
40
pF
50
GΩ
18
pF
1.6
GΩ
18
Pf
1.6
GΩ
500
pF
200
pF
500
pf
33
pF
18
pf
5
GΩ
22
3.Materials and Methods
2
1
1
) //
//( Rin //
)
sCm sCs
sCin
Vo  Vs
2
1
2
1
1
//{Rsk  ( Rc //
)  [( Rb 
) //
//( Rin //
)]}
sCg
sCc
sCm sCs
sCin
2
1
2
1
[
// Rsk  ( Rc //
)] //( Rb 
) //( Rin //
)
sCg
sCc
sCm
sCin
 AsVo
1
2
1
2
1

//{[ Rsk  ( Rc //
)] //( Rb 
) //( Rin //
)}
sCs sCg
sCc
sCm
sCin
( Rb 
∵
2
𝑆𝐶𝑔
≫
𝑅𝑠𝑘 + 𝑅𝑐//
1
𝑆𝐶𝑐
+
𝑅𝑏 +
2
𝑆𝐶𝑚
//
1
𝑆𝐶𝑠
// 𝑅𝑖𝑛//
1
𝑆𝐶𝑖𝑛
23
3.Materials and Methods
∴
1
// Rb)
sCc
Vo  Vs
 AsVo
1
1
1
1
( Rc //
)  ( Rb //
)
 ( Rc //
// Rb)
sCc
sCs
sCs
sCc
( Rb //
⇒ Vo
Vs

1
)
sCs
( Rc //
Rb(1  sRcCc )
Rb  Rc  sRbRc ((1  As )Cs  Cc )
24
3.Materials and Methods

Electrode
Gain(As)
(a)Eleg1n
b
NA

(a)
(b)
As gain
(b)Eleg01
(c)Eleg09
1
0.9
The equivalent circuit of
individual electrode
(c)
25
3.Materials and Methods

Analog circuit
–
Analog circuit flowchart of the measurement circuit
26
3.Materials and Methods

Analog circuit
–
second-order high-pass circuit
GS 2
H ( s)  2
S  S   2
f HPF 
1
2 R3  R 4  C1  C 2
27
3.Materials and Methods

Analog circuit
–
second-order Low-pass circuit
GS 2
H ( s)  2
S  S   2
f HPF
1

2 R7  R8  C 3  C 4
28
3.Materials and Methods

Analog circuit
–
Notch filter circuit
2  S 2
H ( s) 

2
S  2
Q
f HPF 
1
2 R10  R11  C 5  C 6
29
3.Materials and Methods

Driven-right-leg
– To minimize the common-mode interference of the
subjects during ECG measurement, the driven-right-leg
(DRL) electrode method was adopted in the system
30
3.Materials and Methods

Signal processing
–
Type Cascade form and Direct form Butterworth design a
five order low-pass filter cut-off frequency 20Hz and
notch filter
– 60Hz stop-band filter (Notch) to filter out noise in utility
power
31
3.Materials and Methods

Signal processing
–
Filter system transfer function
M
H ( z) 
m
b
z
m
m 0
N
n
a
z
 n
b0  b1 z 1      bM z M

1  a1 z 1      a N z  N
n 0
M
N
k 0
k 1
y (n)   bk x[n  k ]   a k y[n  k ]
32
3.Materials and Methods

Signal processing
–
Direct form structure diagram
33
3.Materials and Methods

Digital Circuits
–
System Architecture
34
3.Materials and Methods

GUI
35
3.Materials and Methods

HRV
◦ Heart rate variability (HRV) analysis attempts to assess
cardiac autonomic regulation through quantification of
sinus rhythm variability
–
–
–
–
Heart Reat：Beat to beat variations in heart rate
MeanRR：Average of all NN intervals
SDNN ：Standard deviation of all NN intervals
RMSSD：Root mean square of the differences between
adjacent NN intervals
36
3.Materials and Methods
• Android
– Android flowchart
37
3.Materials and Methods

Android
38
4. Experiments

The verification experiment
—Analog circuit experiment ①
—Active electrode experiments (Use three gain electrode )
 Each electrode effect of cloth thickness ②
(Ⅰ)0.2mm (Ⅱ)1.4mm (Ⅲ)
2.0mm
 Each electrode Effect of electrode area ③
175cm²
(Ⅰ) 45 cm² (Ⅱ) 100 cm² (Ⅲ)
2
1
3
0.1Hz~100Hz
SIN Wave
39
4. Experiments

The verification experiment
—ECG simulation experiment ④
 Each electrode effect of cloth thickness
(Ⅰ)0.2mm (Ⅱ)1.4mm (Ⅲ)
2.0mm
 Each electrode Effect of electrode area
(Ⅰ) 45 cm² (Ⅱ) 100 cm²
(Ⅲ) 175cm²
40
4. Experiments
Thickness
(area 175cm²)
Signal
generator
bode
Area
(thickness 0.2mm)
Eleg01nb
Thickness
(area 175cm²)
ECG
simulation
Area
(thickness 0.2mm)
……
Eleg01
FFT ,SNR
Eleg09
41
4. Experiments
• Analog circuit experiment ①
—Use the NI USB-6356 to capture entity circuit output
voltage and integrate the data in Matlab
—Use the PSpice simulate the analog circuit and compare
with captured data then show the frequency response graph
42
4. Experiments
• Active electrode experiments
A
C   r 0
d
C: Capacitance
A: Area
d: Distance
εr : Relative permittivity (εr= 1 ,almost air)
ε0: vacuum permittivity (ε0≈8.854×10−12F
m–1)
43
4. Experiments
• Active electrode experiments
Each electrode effect of cloth thickness ②
—Cotton cloths with thicknesses of (Ⅰ)0.2 mm、(Ⅱ)1.4 mm and (Ⅲ)
2.0 mm were inserted between the electrode and the copper plate
44
4. Experiments
• Active electrode experiments
Each electrode Effect of electrode area ③
—The cloth thickness was selected as 0.2 mm
—Three active electrodes with different areas (Ⅰ) 45 cm²、 (Ⅱ) 100 cm²、
(Ⅲ) 175 cm² were examined
(Ⅰ) 45 cm²
(Ⅱ) 100 cm²
(Ⅲ) 175 cm²
45
4. Experiments
• ECG simulation experiment ④
– FLUKE MPS450 simulat the ECG
signal,output voltage is 2 mv

The definition of SNR：Noise is
defined before 0.5Hz and after 20
Hz, signal is defined 0.5 Hz~20 Hz

SNR = 20log
𝑃0.5𝐻𝑧~20𝐻𝑧
𝑃<0.5𝐻𝑧+𝑃>20𝐻𝑧
46
5. Results and Discussion
• Analog circuit experiment ①
– The actual circuit figure
47
5. Results and Discussion
• Analog circuit experiment ①
– All filter
– PSpice circuit simulation frequency response
48
5. Results and Discussion
• Analog circuit experiment ①
– All filter circuit Bode
49
5. Results and Discussion

Analog circuit experiment ①
– Combined the actual circuit result and Pspice result
50
5. Results and Discussion
• Active electrode experiments
– The actual circuit diagram (Eleg1nb)
51
5. Results and Discussion
• Active electrode experiments
– The actual circuit diagram (Eleg01)
52
5. Results and Discussion
• Active electrode experiments
– The actual circuit diagram (Eleg09)
53
5. Results and Discussion
• Active electrode experiments
— Each electrode effect of cloth thickness ②
(ｂ) Eleg01
(a) Eleg1nb
(c) Eleg09
54
5. Results and Discussion
• Active electrode experiments
—Each electrode Effect of electrode area ③
(b) Eleg01
(a) Eleg1nb
(c) Eleg09
55
5. Results and Discussion

ECG simulation experiment ④
— Each electrode effect of cloth thickness
(a) Eleg1nb
(a.1) Eleg1nb 2mv 0.2mm
2.0mm
0.2mm
(a.2) Eleg1nb 2mv 1.4mm
(a.3) Eleg1nb 2mv 2mm
56
5. Results and Discussion

ECG simulation experiment ④
— Each electrode effect of cloth thickness
(b) Eleg01
(b.1) Eleg012mv 0.2mm
2.0mm
0.2mm
(b.2) Eleg01 2mv 1.4mm
(b.3) Eleg01 2mv 2mm
57
5. Results and Discussion

ECG simulation experiment ④
— Each electrode effect of cloth thickness
(c) Eleg09
(c.1) Eleg09 2mv 0.2mm
2.0mm
0.2mm
(c.2) Eleg09 2mv 1.4mm
(c.3) Eleg09 2mv 2mm
58
5. Results and Discussion

ECG simulation experiment ④
—Each electrode Effect of electrode area
(a) Eleg1nb
(a.1) Eleg1nb 2mv 45 cm²
175cm²
45cm²
(a.2) Eleg1nb 2mv 100 cm²
(a.3) Eleg1nb 2mv 175 cm²
59
5. Results and Discussion

ECG simulation experiment ④
—Each electrode Effect of electrode area
(b) Eleg01
(b.1) Eleg01 2mv 45 cm²
45cm²
175cm²
(b.2) Eleg01 2mv 100 cm²
(b.3) Eleg01 2mv 175 cm²
60
5. Results and Discussion

ECG simulation experiment ④
—Each electrode Effect of electrode area
(c) Eleg09
(c.1) Eleg09 2mv 45 cm²
45cm²
100cm²
(c.2) Eleg09 2mv 100 cm²
(c.3) Eleg09 2mv 175 cm²
61
5. Results and Discussion

ECG simulation experiment ④


Each electrode effect of cloth thickness
Electrode
(a)Eleg1nb
(b)Eleg01
(c)Eleg09
200um
36.0361
35.5718
36.0776
1.4mm
32.7203
34.1186
35.7779
2.0 mm
30.2519
32.5634
35.3762
Each electrode Effect of electrode area
Electrode
(a)Eleg1nb
(b)Eleg01
(c)Eleg09
45cm²
34.2720
34.5025
33.5811
100cm
35.7759
34.9723
35.2389
175cm²
36.0361
35.5718
36.0776
62
5.Conclusions and Future Work

Measure the electrodes impedance (three thickness ,three
area)
Measurement of ECG from human and comparison
between the Eleg09(175 cm² , 0.2mm) electrode ECG
and standard ECG measurements
 Communication between Mobile Device and Server

63
References
[1] O. Casas and R. Pallas-Areny, "Electrostatic Interference in Contactless
Biopotential Measurements," in Engineering in Medicine and Biology Society,
2007. EMBS 2007. 29th Annual International Conference of the IEEE, 2007, pp.
2655-2658.
[2] T. Wartzek, T. Lammersen, B. Eilebrecht, M. Walter, and S. Leonhardt,
"Triboelectricity in Capacitive Biopotential Measurements," Biomedical
Engineering, IEEE Transactions on, vol. 58, pp. 1268-1277, 2011.
[3] K. Ko Keun and P. Kwang Suk, "Effective coupling impedance for power
line interference in capacitive-coupled ECG measurement system," in
Information Technology and Applications in Biomedicine, 2008. ITAB 2008.
International Conference on, 2008, pp. 256-258.
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Thank you for your
attention
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