Note: Descriptions are shown in the official language in which they were submitted.
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Device for Jogging data in Braille, corresponding method and corresponding
computer program product
1. Field of the invention
The field of the invention is that of devices comprising a touch-sensitive
surface,
such as a touch-sensitive screen for example.
More specifically, the invention pertains to such devices and their
improvement
with a view to their use by a user having visual deficiency, for example a
visually impaired
or sightless user. Here below, such a user is designated by the expression
"sightless user".
In particular, the invention can be applied to electronic payment terminais
comprising a touch-sensitive surface of this kind and to the keying in of
data, especially
digital data, such as a pin code (four digits and one "enter" key for example)
or a similar
identifier on the touch-sensitive surface of such terminais.
2. Prior art
At present, there is an increasing number of known devices comprising a touch-
sensitive surface, such as mobile telephones, personal digital assistants
(PDAs), laptops,
automatic cash dispensers or again business cash registers.
There also exist electronic payment terminais comprising a touch-sensitive
surface,
for example a touch-sensitive screen. In this case, such a touch-sensitive
screen depicts for
example a virtual keyboard for validating a confidential code or the amount of
a
transaction.
One drawback of these electronic payment terminais however lies in the fact
that
they cannot be used by a sightless user in a simple and confidential marner.
Indeed, unlike
in electronic payment terminais comprising a screen and a keyboard in which
the keys are
in relief and certain keys have a tactile marker on their surface (in
particular, the digit 5
and the "enter", "correct" or "cancel" keys), each key of the virtual keyboard
of an
electronic payment terminal comprising a touch-sensitive screen can only be
detected
visually.
There also exist devices, such as graphics tablets or personal digital
assistants
(PDAs) comprising a touch-sensitive surface on which a user can plot curves to
key in data
on the touch-sensitive surface, for example alphanumerical data, the keyed-in
data being
then processed by a character recognition application. These devices, which
make it
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possible to key in or "draw" data by means of a "continuous" une on the touch-
sensitive
surface, are flot easy to use for a sightless user. In addition, in the case
of electronic
payment terminais, such keying-in operations do flot comply with the security
constraints
laid down in the field of banking transactions. It would indeed be easy for a
malicious
observer to detect the digits being drawn on the touch-sensitive screen and
then to
reproduce them.
There is therefore a need for novel portable devices comprising a touch-
sensitive
screen or a touch-sensitive surface enabling them to be used by any user,
including
sightless users.
3. Goals of the invention
The invention is therefore aimed at providing a solution that does not have
the
drawbacks described here above in proposing a device with a touch-sensitive
surface that
can be used by any user, including a sightless user.
It is thus an object of the invention to provide a device of this kind that is
also
ergonomical and intuitive for the user, whether sighted or sightless.
It is another goal of the invention to provide a low-cost and easy-to-
manufacture
device of this kind.
It is yet another goal of the invention to provide a device of this kind that
complies
with the requirements of security and confidentiality prevailing in the field
of application
of the device. In particular, the invention is therefore aimed at providing a
technique which
prevents or at least makes it difficult for a malicious individual to read the
data introduced
into a touch-sensitive surface.
4. Summary of the invention
The invention proposes a novel solution to this problem in the form of a
device for
keying in data in Braille, the device comprising a touch-sensitive surface.
The device of the invention in one embodiment implements:
means for detecting a plurality of relative presses on the touch-sensitive
surface, the plurality of relative presses being intended to form a Braille
character;
means for building an image formed by dots associated with the plurality of
relative presses, taking account of of least one predetermined criterion for
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adjusting the position of the dots corresponding to the relative presses
detected;
means for recognizing the Braille character as a function of an analysis of
the image.
A device of this kind makes it possible, for example for a user having visual
deficiency, to key in data in Braille on a touch-sensitive surface, for
example to key in a
confidential code or an amount of a transaction when the device is an
electronic payment
terminal. Thus, a sightless user finds himself in a familiar Braille writing
environment, and
this makes such a device more ergonomical for him than a device providing a
"classic"
writing environment.
Furthermore, such a device is compatible with the high security requirements
related to electronic payment terminais. Indeed, a malicious individual
observing a
sightless person keying into the touch-sensitive surface in Braille, i.e. by
successive or
simultaneous presses representing the dots of the Braille characters, would
find it difficult
to recognize what this sightless person is keying in with the intention of
reproducing it. For
these are only dots or groups of dots struck with one or more fingers and not
a line which
can be observed from a distance.
In standard Braille, a character is represented in a matrix of six dots on two
columns, each character being formed by one to six dots (in relief in the case
of rendering
on paper). These dots are conventionally numbered from top to bottom and from
left to
right. The term "Braille character" is understood here to mean especially a
layout of this
kind in the six-dot matrix, such as for example Braille characters defined in
the
corresponding alphabet (a character representing a letter or else a character
representing a
digit, a character indicating a digit, punctuation or other symbols) or
characters specifically
defined for a particular context and corresponding for example to a word, a
sequence of
words or again a symbol, etc. However, the invention can be applied fo a
slightly different
format (number of dots considered, distribution of dots, etc) and/or another
alphabet (a
different characterization of the letters or digits on the matrix of dots).
For example, the means for detecting presses on the touch-sensitive surface of
the
device enable the detection of different keying-in operations (the plurality
of presses)
relative to each digit forming a confidential code.
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The means for building the keying in device then make it possible to convert
these
presses into dots of an image using 2D coordinates of the detected presses so
as to form an
image corresponding to the plurality of presses detected on the touch-
sensitive surface. In
this way, a representation is obtained of the data keyed in by the user in the
form of an
image which is then analyzed so as to recognize or not recognize a Braille
character. For
example, the image obtained from the plurality of presses can be compared with
a
predetermined set of Braille characters.
It must be noted that only the relative position between the presses is
necessary to
build the image, regardless of the position of the presses on the touch-
sensitive surface
(centered or not, towards the top or towards the bottom). Again, this makes a
remote
detection of the keyed in data more complex.
According to one particular embodiment of the invention, the touch-sensitive
surface is suited to the simultaneous keying in of at least two relative
presses so that at
least two constituent dots of the Braille character are keyed in
simultaneously.
In this way, the complete keying in of a piece of data in Braille is quicker,
it being
possible to key in certain dots that form it simultaneously with simultaneous
presses on the
touch-sensitive surface.
In addition, according to this embodiment, the means for detecting can
directly
obtain the relative positions of the simultaneous presses. The detection of
the keyed in data
is therefore made more reliable, as also the building of the associated image.
Furthermore, this type of keying in further increases the difficulty of remote
detection by a malicious person (it is indeed not easy to identify the
position of two or
three fingers applied simultaneously to know whether there bas really been
this number of
presses or whether a finger is waiting in mid-air and to detect whether the
presses
correspond to a left-hand zone or right-hand zone of the matrix, its upper
part or its lower
part, etc).
According to another particular aspect of the invention, the means for
detecting
comprise means for measuring a period of time between two successive presses
so that
presses made within the period of time belong to the plurality of presses when
the period of
time measured is smaller than a predetermined reference period of time.
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In this way, the user can enter several pieces of data in Braille successively
in
separating them by a period of time greater than that needed to key in
different elements of
a same piece of data (without needing a specific operation to validate the
keying in of each
piece of data).
Indeed, according to this embodiment, the means for detecting are capable of
distinguishing successive presses according to the period of time between
them, for
example by comparing the period of time with a predetermined threshold. In
this way, if a
period of time greater than the threshold is measured between two successive
presses, the
means for detecting consider these successive presses as not belonging to a
same plurality
of presses and therefore the means for building an image consider the
associated dots as
not belonging to a same image. In this case, at least two pieces of Braille
data are detected,
for example two digits.
According to another embodiment of the invention, the means for recognizing
are
capable of recognizing at least one control command, i.e. a distinct piece of
data of a
Braille character.
For example, in the case of the keying in of a confidential code, this control
command can correspond to a cancellation of the previous keying-in operation
("Cancer),
to a correction of the previous keying-in operation ("Correct"), or again to a
validation of
the previously performed keying-in operations ("Enter"). Furthermore, such a
command
can also correspond to a special Braille character used to indicate a numeral
character.
Such a command can also correspond to a predefined sign corresponding to the
word
"YES" or to the word "NO" if necessary.
Thus, for example, the device is capable of recognizing a complete keying in
of a
confidential code, including the final validation indicating that the user has
terminated bis
keying-in operation, enabling a sightless user to be independent for the
complete keying in
of such a confidential code in Braille.
According to one particular aspect of the invention, at least one of the
control
commands corresponds to a movement on the touch-sensitive surface and the
means for
detecting are capable of detecting a movement on the touch-sensitive surface.
Thus, the
means for detecting are not only capable of detecting a plurality of
successive presses,
whether simultaneous or not, but are also capable of detecting a particular
keying-in
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operation on the touch-sensitive surface, corresponding for example to a
lengthy and
mobile press on the surface. Thus, according to this embodiment, a piece of
data to be
keyed in can be defined otherwise than by a succession of presses, as in the
case of a
"classic" Braille character. For example, this keying-in operation can
correspond to a
horizontal or vertical movement on the touch-sensitive surface.
According to one embodiment of the invention, the means for building comprise
means of vertical and/or horizontal alignment of dots keyed in at different
instants. Thus,
when certain dots corresponding to successive presses are not quite aligned,
the means for
building the image can realign them according to certain criteria. One such
criterion
corresponds for example to a maximum deviation beyond which the means for
building the
image consider it to be the case that the dots should not be aligned.
According to this embodiment, it is therefore possible to take account of a
lack of
precision of the keying-in operation due to the fact that the user does not
have any marker
available on the touch-sensitive surface and that his finger can deviate
slightly between two
successive presses, whereas he would like them to be aligned.
According to one particular aspect of the invention, the means for building
comprise means for detecting and/or correcting a deviation between two dots.
Here again, according to this embodiment, certain deficiencies of precision in
keying in can be corrected, as in the case for example of a non-compliant
deviation
between two dots. Thus, the means for building the image take account of the
fact that the
pieces of data keyed in by the user are chiefly Braille characters, i.e. sets
of dots positioned
in a matrix with two columns and three rows as already described. For example,
when two
dots are far too distant from one another even though they belong to a same
representation
of a Braille character, the means for building reduce the deviation between
the two dots so
that the image built can then be compared with the different possible Braille
characters.
According to another aspect of the invention, the device furthermore comprises
means for the secured rendering of the recognized Braille character in audio
and/or tactile
form.
Thus, the user can check whether his keying in operation is in conformity with
his
intention before validating it, thus preventing keying-in errors. This
embodiment proves to
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be particularly advantageous when keying in a confidential code for which a
limited
number of errors is permitted.
According to this embodiment, when the safety standards permit it, the
recognized
Braille character can be rendered in a secured manner to the user in audio
form,
confidentially, for example through an earpiece connected to the device. The
secured
rendering can also be tactile, for example through a touchpad placed beneath
the device
and enabling the rendering of a Braille character, for example by means of a
strip of small
pins rising or descending in order to compose the characters.
The invention also pertains to a method for keying in data in Braille
comprising a
touch-sensitive surface.
According to the invention, such a method comprises the following steps:
detecting a plurality of relative presses on the touch-sensitive surface, the
plurality
of relative presses being intended to form a Braille character,
building an image formed by dots associated with the plurality of relative
presses as
a function of at least one predetermined criterion for adjusting a position of
the dots
corresponding to the relative presses detected;
recognizing the Braille character as a function of an analysis of the image.
Such a method can be implemented in a device for keying in as described here
above.
Finally, the invention pertains to a computer program characterized in that it
comprises program code instructions for implementing the method as described
here above
when this program is executed by a processor.
5. List of figures
Other characteristics and advantages of the invention shah l appear more
clearly
from the following description of a particular embodiment given by way of a
simple
illustratory and non-exhaustive example and from the appended drawings, of
which:
Figure 1 illustrates an example of a simplified structure of a keying-in
device
according to one embodiment of the invention;
Figures 2a and 2b respectively present an example of a keying-in device and
the
main pieces of data capable of being keyed in according to one embodiment of
the
invention pertaining to the keying in of a confidential code;
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Figure 3 illustrates the main keying-in steps in the embodiment of figure 2;
Figure 4 illustrates the main steps of the method for keying in according to
one
embodiment of the invention.
6. Description of one embodiment of the invention
6.1 General principle
The general principle of the invention relies on the detection of a plurality
of
presses on a touch-sensitive surface of a keying-in device enabling the
recognition of a
Braille character keyed-in by the user.
Thus, a sightless user, familiar with Braille writing, can key in data in
Braille on a
touch-sensitive screen for example to validate a bank transaction through the
keying in of a
confidential code.
According to the general principle of the invention, once the plurality of
presses has
been detected, the device builds an image formed by dots corresponding to the
plurality of
presses to obtain a representation of the piece of data keyed in by the user.
This
representation is then analyzed so as to recognize the Braille character or
predefined
command to which it corresponds.
6.2 Description of one embodiment
Referring to figure 1, an example is presented of a simplified structure of a
keying-in
device 10 according to one embodiment of the invention.
The keying-in device 10 comprises first of ah l means 101 for detecting a
plurality of
presses on the touch-sensitive surface, for example by means of a stylus or
else a finger of
the user, this plurality of presses being intended to form a Braille character
as defined here
above, i.e. a known character of the Braille alphabet or else a character
defined specifically
to represent a word, a symbol, etc.
The means 101 for detecting according to this embodiment detect the
coordinates of
the presses on the touch-sensitive surface so as to then transmit them to the
means for
building an image representing the piece of data keyed in by the user.
For greater efficiency and precision of detection, the means 101 for detecting
comprise especially means for measuring a period of time between two
successive presses.
In this way, presses performed in a period of time smaller than a
predetermined
reference period of time are considered to belong to the plurality of presses
and are
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therefore intended to form a Braille character. By contrast, two successive
presses
separated by a period of time greater than a predetermined reference period of
time are
considered to belong to two successive pluralities of presses.
According to one alternative of this embodiment, the touch-sensitive surface
of the
keying-in device also is suited to the simultaneous keying in of at least two
presses so that
at least two constituent dots of the Braille character can be keyed in
simultaneously. The
means 101 for detecting are therefore also capable of detecting at least two
simultaneous
presses.
This variant makes it possible especially for the user to carry out a faster
keying-in
operation.
Besides, this variant reinforces the security of a keying-in device used to
key in a
confidential code for example, since it is even more difficult to identify at
least two
simultaneous presses on a touch-sensitive surface to deduce from them the
Braille
character being keyed in.
According to another alternative embodiment, the means for detecting are
capable of
detecting a movement on the touch-sensitive screen instead of a brief press
classically used
to key in a dot of a Braille character. For example, a movement of this kind
can correspond
to a lengthy and mobile press which may be horizontal or vertical on the touch-
sensitive
surface.
In particular, such keying-in operations correspond to a movement used to
define
control commands such as for example the validation of a keying-in operation
or again a
"yes" or "no" response. Such keying-in operations actually make it possible to
define a
command, or an action, with a single specific Braille character.
Once the plurality of presses has been detected by the means 101 for
detecting, it is
processed by means 102 for building an image which associate a dot on an image
with a
detected press, through the coordinates of the pressure movement so as to
obtain a 2D
representation of the presses performed by the user.
Besides, since the goal of the invention is to recognize a Braille character
keyed in by
a user, i.e. chiefly a set of dots contained in a matrix of six dots on two
columns, the means
102 for building an image may include means for adjusting the location of the
dots
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corresponding to the presses detected in order to take account of the lack of
precision of
position in the keying-in operation.
In particular, according to one alternative embodiment, the means 102 for
building an
image comprise means of vertical and/or horizontal alignment of dots keyed in
at different
points in time.
Thus, the image is built according to a matrix with six predefined locations
and if the
coordinates of certain detected presses do not correspond precisely to these
locations, the
means of alignment make it possible to position the dots by modifying their
coordinates
according to predetermined criteria. For example, a predetermined criterion
corresponds to
a maximum deviation between the coordinates of a detected press and the
position of a dot
of the matrix. Beyond this deviation, the means of alignment are not applied.
If a control command is detected by the means for detecting, in the form of a
shifting
on the touch-sensitive surface, the means for building the image represent for
example the
shifting by a succession of aligned dots of decreasing sizes, as described
here below with
reference to figure 2b.
Once the image has been built, it is analyzed by means 103 for recognizing
Braille
characters. For example, the means for recognizing compare the image with a
predetermined set of Braille characters and deliver a recognition decision.
This decision can be negative if the image does not correspond to any Braille
character of the set.
In the case of a positive comparison, the means for recognizing deliver for
example
the alphanumeric value of the recognized Braille character or again the symbol
represented
by the recognized Braille character.
Figure 4 illustrates the main steps of the method for keying in according to
this
embodiment, capable of being implemented in a keying-in device as described
here above.
The first step 40 for detecting presses consists in detecting the coordinates
of the
presses on the touch-sensitive surface which are then processed during a step
41 for
building an image representing the piece of data keyed in by the user.
Once this image has been built, a step 42 for recognizing a Braille character
is
implemented, delivering a positive recognition result, for example the
recognized Braille
character, or a negative recognition result.
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6.3 Description of an example of an application of the invention
Referring now to figures 2a, 2b and 3, an example is presented of an
application of
the invention in an electronic payment terminal having a touch-sensitive
surface enabling
the keying in of a four-digit confidential code in Braille.
It must be noted that the Braille characters represented in this example of an
application belong to the Braille alphabet in English by way of an
illustratory and non-
exhaustive example. The use of Braille characters in any other alphabet is
obviously
possible according to the invention.
Figure 2a represents a terminal of this kind in which a Braille character has
been
entered by a user.
Figure 2b for its part presents the different Braille characters recognizable
in the
context of such an application, i.e. especially the numeral characters
representing the digits
1 to 9 as well as the special numeral indicator character classically keyed in
before a
numeral character as well as Braille characters representing commands such as
the
command for correcting the previous keying-in operation, the command for
cancelling the
previous keying-in operation and the "enter" command (which besides is
identical to the
special numeral indicating character).
Thus, as illustrated in figure 3, in this context of keying in a confidential
four-digit
code, the user must first of ah l key in the numeral indicator character and
then the four
digits of his confidential code (2497 in the example of figure 3) and finally
the "enter"
character.
It may be recalled that according to one particular embodiment of the
invention, the
user can key in several simultaneous presses on the touch-sensitive surface.
Furthermore, the keying in of the first special numeral indicating character
can also
enable the defining of the orientation of the touch-sensitive surface, namely
in portrait or
landscape mode, so as to facilitate the detection of subsequent presses.
When the user starts keying in the Braille characters listed here above, the
means for
detecting detect the different corresponding presses.
As described here above, the means for detecting can implement means for
measuring a period of time between two successive presses so that it is
possible, through a
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reference period of time, to determine whether two successive presses
constitute a single
Braille character or belong to two successive distinct Braille characters.
For example, when the user keys in the first numeral indicating character, it
is
probable that he does so in at least two stages, a first stage to
simultaneously key in the two
vertical dots at the top right-hand of the character, and a second stage to
simultaneously
key in the two horizontal dots at the bottom of the character. The means for
detecting must
consider these two stages to be close enough to each other for the presses
performed in
these two stages to be considered as constituting a single Braille character.
Besides, the user must comply with a lengthier time interval before starting
to key in
the first figure (2), so that the means for detecting detect the end of the
keying in of one
character and the start of the keying in of a following character.
When the means for detecting detect the end of the keying in of a character,
the
pieces of data corresponding to this keying in are transmitted to the means
for building an
image. These pieces of data are for example the coordinates corresponding to
the different
presses performed by the user, for example four presses for the numeral
indicating
character.
These coordinates are then processed by the means for building an image so as
to
obtain a 2D representation of the dots corresponding to the presses keyed in
by the user.
As already indicated here above, the means for building an image can implement
means for adjusting coordinates of the presses keyed in, for example by
aligning presses
vertically and/or horizontally, as a function of predetermined criteria.
Similarly, the means for building an image can also implement means for
detecting
and/or correcting a deviation between two dots as a function of predetermined
criteria so as
to make it possible to obtain an image potentially corresponding to a Braille
character, i.e.
dots laid out in a matrix of three rows and two columns. For example, these
means for
correcting a deviation between two dots are implemented only when the
deviation detected
is smaller than a threshold.
Once the image bas been built, it is analyzed by the means for recognizing
Braille
characters so as to know which character has been keyed in by the user.
It is recalled that the means for recognizing are capable of recognizing flot
only a
prior-art Braille character coming from a Braille alphabet but also control
commands
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represented by specific Braille characters such as for example a particular
layout of dots in
the classic matrix of six dots on three rows in two columns ("enter" command
illustrated in
figure 2b) or a succession of horizontal or vertical dots ("cancel" command
illustrated in
figure 2b) or again a representation of a shift detected on the touch-
sensitive surface
("correct" command illustrated in figure 2b).
The analysis of the image consists for example in comparing this image with a
set of
representations of reference Braille characters such as those represented in
figures 2b.
After analysis, the means for recognizing deliver a positive or negative
result of
recognition.
The result is negative when, according to the means for recognizing, the image
does
not correspond to a Braille character.
The result is positive when the image corresponds to a Braille character and,
in this
case, the means for recognizing deliver for example the recognized character
in the
corresponding alphanumerical form, or the title of the recognized control
command.
For example, when the recognized Braille character corresponds to the digit 2,
it is
this digit that is delivered.
When the "Enter" command is recognized, then the means for recognizing deliver
an
indication that the keying in has ended, making it possible, in the context of
the application
described, to implement the classic application for validating the
confidential code keyed
in by the user.
According to one variant of this example of an application, the keying in
device also
comprises means of secured rendering of the recognized Braille character in
audio form
and/or tactile form so as to interact with the user. Thus, the user can
confirm or negate a
keying in operation before performing the next keying in operation.
This variant is advantageous for the use of the electronic payment terminal by
a
sightless user who is not capable of visually verifying the validity of his
keying-in
operation and especially when the keying-in operation corresponds to a
confidential code.
Indeed, this makes it possible for such a user not to be penalized by the
security rules laid
down in this field of application where, especially, only three successive
attempts are
allowed for keying in a confidential code.
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If the user has secured means available for verifying each piece of Braille
data keyed
in, he runs a smaller risk of keying in errors and hence a smaller risk of
rejection of the
keying in of his confidential code.
Besides, according to yet another variant of the invention, the keying in
device may
comprise "classic" keys outside the touch-sensitive surface for the control
commands such
as "Enter", "Correct", or "Cancel". This variant makes the keying in of a
confidential code
faster and more precise, since the classic keys are marked as in a classic
electronic
payment terminal and can therefore be recognized by a sightless user through
touch.
