HoliBraille: Multipoint Vibrotactile Feedback on Mobile Devices
UbiBraille: Designing and Evaluating a Vibrotactile Braille-Reading Device.
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Transcript of UbiBraille: Designing and Evaluating a Vibrotactile Braille-Reading Device.
UBIBRAILLE Designing and Evaluating a Vibrotactile Braille-Reading Device
HUGO NICOLAU JOÃO GUERREIRO TIAGO GUERREIRO LUÍS CARRIÇO
motivation :: constantly online
blind users :: auditory feedback
challenge :: alternative modality
problem :: deaf-blind users
problem :: mobile usage
problem :: noisy environments
problem :: privacy
earphones?
goal :: inconspicuous and private
related work
[Al-Qudah et al, 2011] [Jayant et al, 2010]
[Ohtsuka et al, 2008] [Rantala et al, 2009]
our approach :: UbiBraille
inspiration :: perkins brailler
example :: ‘a’
example :: ‘b’
same approach for reading
ubibraille :: hardware
Six rings
Lilypad vibe board
Vibration motor (10 mm), 3,8 Volts
Arduino Mega ADK board
ubibraille :: ‘b’
advantage :: mnemonic
advantage :: speed
1. Will participants be able to discriminate simultaneous stimuli?
2. Will participants be able to leverage Braille knowledge?
3. What are the most common error patterns?
user study :: character recognition
11 blind participants (8 male, 3 female) Ages 21 – 61 (m=45, sd=16)
Braille typists
assessment :: braille proficiency
user study :: procedure
user study :: procedure
1. Audio signal 2. Delay (2 seconds)
3. Random braille character (from 26 letters)
4. Answer 5. Monitor register answer
26 le
tter
s x
2 bl
ocks
results :: character recognition
0%
10%
20%
30%
40%
50%
60%
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 overall accuracy
82% sd=17.25%
0%
10%
20%
30%
40%
50%
60%
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
error rate per character
32% 32% 32%
55%
36%
0%
10%
20%
30%
40%
50%
60%
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
‘novyz’ are harder
32% 32% 32%
55%
36%
0%
10%
20%
30%
40%
50%
60%
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
N O V Y Z‘novyz’ are harder
error pattern :: 1 finger issues
51.6%
N O V Y Z
Q R1 finger error :: insertion
N O V Y Z
Q R U X U1 finger error :: omission
error pattern :: 2 finger issues
25.3%
Z X
25.3% error pattern :: 2 finger issues
accuracy rate per participant
0%
20%
40%
60%
80%
100%
P1 P2 P3 P4 P5 P6 P7 P8 P9 P10 P11
0%
20%
40%
60%
80%
100%
P1 P2 P3 P4 P5 P6 P7 P8 P9 P10 P11
result :: individual differences
[rho=.571, p=.066, N=11]
leverage braille knowledge :: reading
[rho=.627, p=.039, N=11]
leverage braille knowledge :: writing
Memory
82% overall accuracy
More fingers, more errors
Mostly 1-finger errors
Leverage braille knowledge
character recognition :: major results
user study #2 :: word recognition
7 blind participants (from study #1) Ages 21 – 62
user study :: participants
1. Audio signal 2. Delay (2 seconds)
3. Random word 4. Answer 5. Monitor register answer
2 tim
es
user study :: procedure
stimulus interval
‘a’ ‘c’ ‘t’ ‘o’ ‘r’
Condition Stimulus (ms) Interval (ms)
4000ms 2000 2000
2000ms 1000 1000
1000ms 500 500
500ms 250 250
user study :: conditions
user study :: design
4 conditions (randomized) 10 words per condition 280 trials 5 characters per word Commonly used words (Portuguese)
results :: word recognition
recognition accuracy rate
93% 89% 64% 33% 0%
20%
40%
60%
80%
100%
4000ms 2000ms 1000ms 500ms
Error bars denote 95% CI
93% 89% 64% 33% 0%
20%
40%
60%
80%
100%
4000ms 2000ms 1000ms 500ms
Error bars denote 95% CI
No sig. diff. p>.05
recognition accuracy rate
93% 89% 64% 33% 0%
20%
40%
60%
80%
100%
4000ms 2000ms 1000ms 500ms
Error bars denote 95% CI
Z=-2.041, p<.05
recognition accuracy rate
93% 89% 64% 33% 0%
20%
40%
60%
80%
100%
4000ms 2000ms 1000ms 500ms
Error bars denote 95% CI
Z=-2.379, p<.05
recognition accuracy rate
leverage braille knowledge :: reading and writing
[rho=.805, p<.05, N=7]
[rho=.543, p=.208, N=7]
Identify through context
word recognition :: ease of use
Condition Median IQR 4000ms 5 1 2000ms 5 2 1000ms 3 2 500ms 2 1
likert scale [1-5] : 5 is better
longest durations are easier
Condition Median IQR 4000ms 5 1 2000ms 5 2 1000ms 3 2 500ms 2 1
likert scale [1-5] : 5 is better
Z=-2.530, p<.05
Z=-2.428, p<.05
Condition Median IQR 4000ms 5 1 2000ms 5 2 1000ms 3 2 500ms 2 1
likert scale [1-5] : 5 is better
longest durations are easier
1s duration + 1s interval à 90%
leverage braille knowledge
12 wpm
room for improvements
word recognition :: major results
conclusion :: ubibraille
conclusion :: inconspicuous communication
conclusion :: leverage braille-related abilities
conclusion :: character- and word-level results
future work :: ubibraille
future work :: finger discrimination
future work :: new applications
future work :: multi-point feedback
The End. HUGO NICOLAU [email protected] paper and slides @ http://web.ist.utl.pt/hugo.nicolau