Hi, my name is Viktorija Paneva, from the University of Bayreuth.
I will present HaptiRead: Reading Braille as Mid-Air Haptic Information.
This was a joined effort with Sofia Seinfeld, Michael Kraiczi and Jörg Müller.
With HaptiRead we evaluate the possibility of presenting Braille information as touchless
stimulation using mid-air haptic technology.
HaptiRead delivers the information directly to the user’s palm, in an unobtrusive manner,
which makes it particularly suitable for delivering short messages in public spaces, such as,
for reading the departure time of the next bus at a bus stop.
There are several challenges that blind people face when engaging with interactive displays
in public spaces.
With audio displays, it is difficult to maintain personal privacy.
Audio feedback is easily overheard by bystanders and can be perceived as obtrusive, since it
contributes to the environmental noisescape.
Some interfaces, such as ATMs, feature a headphone plug.
In this case, however, users need to remember to bring their headphones and once they start the
interaction, they might have more difficulty monitoring events in their immediate surroundings.
Refreshable Braille displays, consist of lines of actuated pins. They can be difficult to
detect from a distance, since the user has to touch them to know they are there.
The physical contact with these interfaces could potentially cause hygiene problems.
They contain moving parts, which can become clogged by dirt and slower over time.
The information is limited to patterns of dots, which is suitable for
text, but not sufficient for content involving shapes, like for example data charts.
Other methods and devices for reading Braille include:
HoliBraille - a system consisting of six vibrotactile motors and dampening elements
that can be attached to mobile devices.
V-Braille is a method for presenting Braille characters on a mobile phone, where the touchscreen
is divided into six cells.
When a cell representing a raised dot is touched, the phone vibrates.
Then, UbiBraille is a wearable device consisting
of six aluminum rings that transmit vibrotactile feedback. And, lastly,
Luzhnica et al. investigated encoding text using a wearable haptic display,
in a hand, forearm and two-arms configuration.
In this study, we use mid-air haptic display that is composed of
transducers, that emit ultrasonic waves with
phases, such that one or several focus points are created in mid-air.
The waves are modulated down to a lower frequency, which can be perceived by the human skin.
So, how does Mid-Air Haptics tackle some of the challenges with traditional Braille displays?
The device includes a hand-tracking sensor, so that the haptics can be rendered direcly on
the palm, up to a distance of 70 cm in mid-air.
There is no contact between the user and the device.
Only the user interacing with the interface at the given time, receives the information.
In addition, the mid-air haptic displays are highly-programmable,
featuring a wide range of haptic sensations that can be rendered.
The contibrutions of our paper are:
We test, for the first time, the use of Mid-Air Haptics for reading Braille with blind participants.
We demonstrate that it is possible to effectively distinguish between different Braille patterns,
rendered using mid-air haptics.
We present and evaluate three different haptic stimulation methods in a user study.
We went through an extensive iterative design process.
First, we brainstormed different ways how the Braille haptic stimulation could be delivered
to the user, which are summarized in the table.
Then we evaluated these methods in interviews with experts, and in a pilot study with 6
and in a preliminary user study with 18 sighted participants.
Through this process, we were able to identify the following three most promising methods:
Constant, where all points are simultaneously presented.
Point-by-Point, where each point is individually presented.
And, Row-by-Row, where points of the same row are presented together.
In the pilot tests, we also determined the
best timespans for displaying the feedback for these methods.
For example, in the Point-by-Point method, the best results were obtained when individual
dots were displayed for 200 ms, with a 300 ms pause between subsequent dots.
The user study consisted of a within-groups experimental design.
The user study was conducted 11 with blind participants,
aged between 19 and 70.
We opted for a simple experimental task that ensures high internal validity and experimental
control.
The task consisted of correctly identifying a pattern of dots, limited to 4-cell Braille
characters. The characters were presented with one of the three possible types of haptic stimulation:
Constant, Point-by-Point, and Row-by-Row, in a randomized order.
Before each experimental session, participants underwent a training session,
consising of 4 trials.
Then, each experimental session consisted of 10 trials per method - 30 in total.
When a participant recognized a pattern, they would state the corresponding character out loud.
We did not give a time limit, but we did record the time to respond.
We obtained an average accuracy of 81% for the Constant, 88% for the Point-by-Point
and 75% for the Row-by-Row method.
The mean time to identify a character was around 7 seconds for all of the methods.
Using the Friedman test, no significant difference was found, both in the Accuracy
and the Mean Time to Respond between the three haptic stimulation methods.
In the semi-structured interview, participants expressed
different preferences, in terms of the haptic stimulation methods.
Some said that the Constant method felt closest to regular Braille,
while others liked that with the Row-by-Row they had an indication on how to orient their hand.
The participants also mentioned tasks in their everyday life, where they could envision using HaptiRead.
For example, to read a prescription at the doctor's office, or to read a menu at a restaurant.
This first validation study was conducted using a small subset of Braille characters,
limited to four cells, individually presented.
Further studies are required to validate the findings using a full 6-cell layout, as well
as presenting the information in context, that is, in words and sentences.
In conclusion, our results provide a first emirical validation
of employing mid-air haptics for reading Braille.
They show that it is possible to convey Braille as touchless haptic stimulation
with all of the three proposed methods: Constant, Point-by-Point and Row-by-Row.
The participants of the study responded quite favourably to the concept.
But furter testing and development is needed
to explore the full potential of the technology for this particular application.
Here are some further potential application scenarios of HaptiRead, for example, for reading
the bank account balance at the ATM.
Thank you for your attention and or more information, please, check out our paper.