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 hugonicolau@computing.dundee.ac.uk paper and slides @ http://web.ist.utl.pt/hugo.nicolau