VSN/1

Performance evaluation of voluntary blinking detection of versatile single switch VSN/1 using

a photo-reflective sensor

○

JALSA JALSA

IT

Daisuke YAJIMA, Niigata University Toyohiko HAYASHI, Niigata University Yoshinobu MAEDA, Niigata University

Tetsuya WATANABE, Niigata University Yuko WAKABAYASHI, Japan ALS Association Prefecture branch in Niigata

Takashi ODA, Japan ALS Association Prefecture branch in Niigata Satoshi WATANABE, Ftech company limited

Akira ABE, Ftech company limited Toshimitsu YAMAGUCHI, Niigata IT Support Center for Persons with Disabilities

Key Words: communication support, ALS, photo-reflective sensor, blink, single switch

1.

ALS

(1)

ALS

(2) (3)

VSN/1(4)-(6)

(4)

ALS

2. VSN/1

3. ALS

4. 5.

2. VSN/1

2-1

Fig. 2 Positioning of the sensor array relative to one of the

subject’s eyes by means of a 3-DOF sensor

attachment secured to an eye-glass

Fig. 1 Photo-reflective sensor array of VSN/1 for blinking

detection fixed on an eye-glass lens, consisting of

three sensors denoted as CH1, CH2 and CH3

CH1

CH2

CH3

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LED

LED

3[mm] 4[mm]

2[mm] NJL5197K-F25(4)-(6)

3

Fig.

1 Fig. 1 3

1 3 CH1 3

3 Fig. 2

12[g](3) 26[g]

2-2

(4)

Fig. 3 CH2

a

b, d, e

c

Fig. 3

Fig. 4

±Vt

2

VRMS 3 Vt = 3×

VRMS

Vt t1 -Vt

t2 tb = t2 - t1

tb

10 3

0.5[s]

tb tmin tb≦tmax

tb

tmin tmin = 0.5[s]

tmax tmax = 3.0[s] tb

tmin tb≦tmax t2

Fig. 4

2-3

2-2 3

3 1

2

Vp Vt

3 Vp

Vp

3 Vp

Vmax

Vpth

Vt tb

Vt

Vt

Vp

Vpth Vpth Vmax

Vpth = Vmax / 2 Vt

Vp≧Vpth

3. ALS

3-1

ALS

VSN/1

(4)

ALS

Fig. 3 An example of signal waveform obtained from the

photo-reflective sensor

Fig. 4 A waveform obtained by differentiating the original

one shown in Fig. 2 and temporal parameter tb defined

by using an amplitude threshold Vt: Other thresholds

Vpth, tmin and tmax are used for distinguishing voluntary

blink from other ones.

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ALS

3-2 3-4

3-2

Fig. 5 ALS 76

1 2

CH2

15[Hz]

20

3-3

3-1

Fig. 6

→ → →

5 10

Visual C++ Microsoft

1 1

12 1

3 3

3 9 3

5

4 1 1

2 1

3

4 1 2

Fig. 6 1

12

3

Fig. 2

3-4

3

2

6

Table 1 n1 n6

n6 n1 n5

5

1 {(n1+n4) (n1+n2+n3+n4+n5)}×100[%]

2 {(n3+n5) (n1+n2+n3+n4+n5)}×100[%]

3 {n2 (n1+n2+n3+n4+n5)}×100[%]

4 {n1 (n1+n2)}×100[%]

5 {n4 (n3+n4)}×100[%]

12

1

4.

3-4 3

Fig. 5 Experimental setup

Fig. 6 Visual stimulation for triggering the voluntary blink

displayed on a computer screen: The color of a

circular region changes from red to green as a trigger

to start the blink.

Table 1 Counting of several events defined as a combination

of input motion and output of the switch

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97.3±0.28[%] 2.2±0.47[%]

0.5±0.33[%] 95.4±3.21[%]

97.5±0.53[%]

t

Fig. 7

Fig. 7-(a) a, c, d

1 b

(b) Fig. 7-(a)

b

5.

VSN/1(4) 94.9±2.05[%]

1.8±1.56[%] 3.3±1.30[%]

97[%]

95[%]

VSN/1 ALS

4.

Fig. 7-(a) b

Fig. 7-(b)

tb

1

2

Vp Vp Vpth

0.5[%]

VSN/1 ALS

(7) VSN/1

(6) VSN/1

ALS

ALS

(1) e-AT , -

-, pp. 21-22, 73-95, , 2003.

(2) , , , ,

, , no. 62, pp. 253-259, 2009.

(3) ,

, 8

, vol. 3 K-007, pp. 533-539, 2009.

(4) , , , , ,

, , ,

VSN/1

, 7

, pp. 63-64, 2009.

(5) , , , , ,

ALS

, WIT2006-125,

vol. 106, no. 612, pp. 115-120, 2007.

(6) , , , , ,

, MBE2007-123, vol. 107, no. 541,

pp. 73-76, 2008.

(7) , , , , ,

ALS ,

, vol. 43, no. 12, pp. 1298-1305, 2009.

(a) An example of signal waveforms caused by periodic

blinks, observed in periods from “a” to “d”

Fig. 7 An example of malfunction resulted from a signal

waveform caused by a periodic blink

(b) The waveforms obtained by differentiating the original

one shown in (a)

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