This document summarizes the design and evaluation of UbiBraille, a vibrotactile braille reading device. The study tested UbiBraille with 11 blind participants in two user studies. The first study tested character recognition accuracy, finding an overall 82% accuracy with harder characters involving 1 or 2 fingers. The second study tested word recognition accuracy under different timing conditions, finding highest accuracy (93%) with the longest (4000ms) stimulus/interval times. Results suggest UbiBraille is effective for braille reading and that leveraging existing braille knowledge improves performance. Future work will explore improving finger discrimination and developing new applications.

1. U BI B RAILLE
Designing and Evaluating a Vibrotactile
Braille-Reading Device
HUGO
NICOLAU
JOÃO
GUERREIRO
TIAGO
GUERREIRO
LUÍS
CARRIÇO

2. motivation :: constantly online

3. blind users :: auditory feedback

4. challenge ::
alternative modality

5. problem :: deaf-blind users

6. problem :: mobile usage

7. problem :: noisy environments

8. problem :: privacy

9. earphones?

10. goal :: inconspicuous and private

11. [Al-Qudah et al, 2011]
[Jayant et al, 2010]
[Ohtsuka et al, 2008]
[Rantala et al, 2009]
related work

12. our approach :: UbiBraille

13. inspiration :: perkins brailler

14. example :: ‘a’

15. example :: ‘b’

16. same approach for reading

17. Six rings
Lilypad vibe board
Vibration motor (10 mm), 3,8 Volts
Arduino Mega ADK board
ubibraille :: hardware

18. ubibraille :: ‘b’

19. advantage :: mnemonic

20. advantage :: speed

21. 1.
Will participants be able to
discriminate simultaneous
stimuli?

22. 2.
Will participants be
able to leverage
Braille knowledge?

23. 3.
What are the most
common error
patterns?

24. 11 blind participants (8 male, 3 female)
Ages 21 – 61 (m=45, sd=16)
Braille typists
user study :: character recognition

25. assessment :: braille proficiency

26. user study :: procedure

27. 26 letters x 2 blocks
1. Audio signal
2. Delay (2 seconds)
3. Random braille character (from 26 letters)
4. Answer
5. Monitor register answer
user study :: procedure

28. results ::
character recognition

29. 82%
60%
50%
40%
sd=17.25%
30%
20%
10%
overall accuracy
0%
a b c d e
f
g h
i
j
k
l
m n o p q
r
s
t
u
v w x
y
z

30. error rate per character
60%
50%
40%
30%
20%
10%
0%
a b c d e
f
g h
i
j
k
l
m n o p q
r
s
t
u
v w x
y
z

31. ‘novyz’ are harder
60%
55%
50%
40%
36%
32% 32%
32%
30%
20%
10%
0%
a b c d e
f
g h
i
j
k
l
m n o p q
r
s
t
u
v w x
y
z

32. ‘novyz’ are harder
N
O
V
Y
Z
60%
55%
50%
40%
36%
32% 32%
32%
30%
20%
10%
0%
a b c d e
f
g h
i
j
k
l
m n o p q
r
s
t
u
v w x
y
z

33. 51.6%
error pattern :: 1 finger issues

34. N
O
Q
R
V
1 finger error :: insertion
Y
Z

35. N
O
V
Y
Z
Q
R
U
X
U
1 finger error :: omission

36. 25.3%
error pattern :: 2 finger issues

37. Z
X
25.3%
error pattern :: 2 finger issues

38. accuracy rate per participant
100%
80%
60%
40%
20%
0%
P1
P2
P3
P4
P5
P6
P7
P8
P9
P10
P11

39. result :: individual differences
100%
80%
60%
40%
20%
0%
P1
P2
P3
P4
P5
P6
P7
P8
P9
P10
P11

40. [rho=.571, p=.066, N=11]
leverage braille knowledge :: reading

41. [rho=.627, p=.039, N=11]
leverage braille knowledge :: writing

42. Memory

43. 82% overall accuracy
More fingers, more errors
Mostly 1-finger errors
Leverage braille knowledge
character recognition :: major results

44. user study #2 ::
word recognition

45. 7 blind participants
(from study #1)
Ages 21 – 62
user study :: participants

46. 1. Audio signal
2 times
2. Delay (2 seconds)
3. Random word
4. Answer
5. Monitor register answer
user study :: procedure

47. ‘a’
‘c’
stimulus
‘t’
interval
Condition
Stimulus (ms) Interval (ms)
4000ms
2000
2000
2000ms
1000
1000
1000ms
500
500
500ms
250
250
user study :: conditions
‘o’
‘r’

48. 4 conditions (randomized)
10 words per condition
280 trials
5 characters per word
Commonly used words (Portuguese)
user study :: design

49. results ::
word recognition

50. recognition accuracy rate
100%
80%
60%
40%
20%
0%
93%
89%
64%
33%
4000ms
2000ms
1000ms
500ms
Error bars denote 95% CI

51. recognition accuracy rate
No sig. diff. p>.05
100%
80%
60%
40%
20%
0%
93%
89%
64%
33%
4000ms
2000ms
1000ms
500ms
Error bars denote 95% CI

52. recognition accuracy rate
Z=-2.041, p<.05
100%
80%
60%
40%
20%
0%
93%
89%
64%
33%
4000ms
2000ms
1000ms
500ms
Error bars denote 95% CI

53. recognition accuracy rate
Z=-2.379, p<.05
100%
80%
60%
40%
20%
0%
93%
89%
64%
33%
4000ms
2000ms
1000ms
500ms
Error bars denote 95% CI

54. [rho=.805, p<.05, N=7]
[rho=.543, p=.208, N=7]
leverage braille knowledge ::
reading and writing

55. Identify through context

56. Condition
4000ms
2000ms
1000ms
500ms
Median
5
5
3
2
IQR
1
2
2
1
likert scale [1-5] : 5 is better
word recognition :: ease of use

57. Condition
4000ms
2000ms
1000ms
500ms
Median
5
5
3
2
IQR
1
2
2
1
likert scale [1-5] : 5 is better
longest durations are easier

58. Condition
4000ms
2000ms
1000ms
500ms
Median
5
5
3
2
IQR
1
2
2
1
Z=-2.530, p<.05
Z=-2.428, p<.05
likert scale [1-5] : 5 is better
longest durations are easier

59. 1s duration + 1s interval à 90%
leverage braille knowledge
12 wpm
room for improvements
word recognition :: major results

60. conclusion ::
ubibraille

61. conclusion ::
inconspicuous communication

62. conclusion ::
leverage braille-related abilities

63. conclusion ::
character- and word-level results

64. future work ::
ubibraille

65. future work :: finger discrimination

66. future work :: new applications

67. future work ::
multi-point feedback

68. The End.
HUGO NICOLAU
hugonicolau@computing.dundee.ac.uk
paper and slides @ http:/
/web.ist.utl.pt/hugo.nicolau