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This paper presents the first attempt to fuse two different kinds of behavioral biometrics: mouse dynamics and eye movement biometrics. Mouse dynamics were collected without any special equipment, while an affordable The Eye Tribe eye tracker was used to gather eye movement data at a frequency of 30 Hz, which is also potentially possible using a common web camera. We showed that a fusion of these techniques is quite natural and it is easy to prepare an experiment that collects both traits simultaneously. Moreover, the fusion of information from both signals gave 6.8 % equal error rate and 92.9 % accuracy for relatively short registration time (20 s on average). Achieving such results were possible using dissimilarity matrices based on dynamic time warping distance.
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Fusion of eye movement and mouse dynamics for reliable
behavioral biometrics
Pawel Kasprowski
Katarzyna Harezlak
Received: 5 November 2015 / Accepted: 11 July 2016 / Published online: 27 July 2016
The Author(s) 2016. This article is published with open access at
Abstract This paper presents the first attempt to fuse two
different kinds of behavioral biometrics: mouse dynamics
and eye movement biometrics. Mouse dynamics were col-
lected without any special equipment, while an affordable
The Eye Tribe eye tracker was used to gather eye movement
data at a frequency of 30 Hz, which is also potentially
possible using a common web camera. We showed that a
fusion of these techniques is quite natural and it is easy to
prepare an experiment that collects both traits simultane-
ously. Moreover, the fusion of information from both sig-
nals gave 6.8 % equal error rate and 92.9 % accuracy for
relatively short registration time (20 s on average).
Achieving such results were possible using dissimilarity
matrices based on dynamic time warping distance.
Keywords Eye movement Mouse dynamics Biometric
1 Introduction
There have been many solutions developed for user iden-
tification including passwords, PINs, access tokens, ID
badges and PC cards, yet they are often inconvenient or
even insufficient due to technological development. People
are provided access to so many secured resources that they
are not able to memorize all the necessary PIN codes and
passwords. That is why so-called biometric identification
that uses human body characteristics (like face, iris or
fingerprint recognition) has gained interest. The most
popular methods utilize mostly physiological patterns of a
human body; however, this makes them vulnerable.
The aforementioned inconveniences led to a search for
new solutions. Biometric identification based on human
behavioral features may solve these problems. There are
various human characteristics to be considered and
explored for the purposes of biometric identification.
Among them voice, gait, keystroke, signature [1] as well as
eye movement and mouse dynamics should be mentioned.
The aim of the paper is to provide a new approach to
biometric identification using a combined feature analysis
based on eye movement and mouse dynamics signals. The
main contribution of the paper is the first attempt to build an
identification model based on a fusion of these two different
biometric traits. For this purpose, a novel experiment that
had not previously been studied was designed. Additionally,
the usage of a dissimilarity matrix [2] to prepare samples for
the classification purpose was introduced.
The paper is organized as follows. The state of the art of
both mouse and eye-movement-based identification is
presented in the second section. The third section describes
the scenario of the experiments, the group of participants
and the experimental setup. Section 4contains details of
the methods used to preprocess and extract features. This is
followed by a description of the evaluation procedure.
Section 5contains results of the experiments. The discus-
sion of these results is presented in Sect. 6. Finally, con-
clusions and future work are provided in Sect. 7.
2 State of the art
Both mouse dynamics and eye-movement-based biometrics
have been studied previously; hence, this section provides
some comparative analyses of previous achievements.
&Pawel Kasprowski
Institute of Informatics, Silesian University of Technology,
ul. Akademicka 16, 44-100 Gliwice, Poland
Pattern Anal Applic (2018) 21:91–103
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2.1 Information fusion in biometrics
Information fusion is a very popular tool for improving
biometric identification system performance. According to
[3], fusion may combine multiple representations of the
same biometric trait, multiple matchers using the same
representation and, finally, multiple biometric modalities.
Multimodal fusion may be done on various levels: (1) a
feature extraction level, in which multiple traits are used
together to form one feature vector; (2) a matching score
level, in which results (typically similarity scores) obtained
from different biometric systems are fused; and (3) a
decision level, in which only output decisions (accept/re-
ject) from different biometric systems are used in a
majority vote scheme.
There are a lot of examples of multimodal biometric
fusions. The most popular are fusions of physiological
modalities like face and iris [4,5] or fingerprint and iris
[6,7]. There are also works that present a fusion of the
same modality measured by different sensors [8]. Finally,
fusions of different algorithms processing the same data on
matching score or decision levels have improved biometric
identification results significantly [9,10].
2.2 Mouse dynamics
Analyzing the research regarding mouse event-based bio-
metric identification, we find various approaches and many
features of mouse movement that have been studied. Data
obtained as a dynamic mouse signal consist of recordings
including low-level mouse events such as raw movement
and pressing or releasing mouse buttons. These are typi-
cally the timestamps and coordinates of an action and can
be grouped in higher-level events such as move and click,
highlight a text, or a drag and drop task. Based on these
aggregated actions, a number of mouse-related features
have been developed and applied for user identification.
Experiments available in the literature may be differ-
entiated by various aspects. The first of them is the type of
experiment, which includes edit text tasks [11], browser
tasks [11,12] and game scenarios [11,13]. Ahmed and
Traore [14] collected data during users’ daily activities.
Similarly, online forum tasks for gathering mouse move-
ment signal were utilized in the studies presented in [15]. A
different type of experiment was proposed in the research
presented in [16], in which a user had to use a mouse to
follow a sequence of dots presented on a screen.
Studies may also be analyzed in terms of the environ-
ments used. In one group of experiments, participants
worked on computers without any specially prepared
environment [11,12,14]. Another approach was to use a
controlled environment to prevent unintended events
influencing the quality of samples [1618]. Zheng and el.
[15] conducted tests in a self-prepared environment
involving routine, continuous mouse activities as well as
using an online forum.
Research can also be classified by the time in which an
authentication takes place. There are studies that collected
such data only at the beginning of the session [16]or
continuously during the whole session [11,13,14,18].
Since data gathered during experiments have to be pro-
cessed to be useful in further analysis, each registered
mouse movement signal is divided into small elements
representing various mouse actions. Among such elements,
several features can be distinguished, forming two types of
vectors: spatial and temporal. The first describes changes in
mouse position and includes mouse position coordinates;
mouse trajectory; angle of the path in various directions;
and curvature and its derivative. The second type of vectors
depicts quantities related to mouse movement like hori-
zontal, vertical, tangential and angular velocities, tangen-
tial acceleration and jerk.
The mouse movement dynamic has also been used in
research applying various fusion methods. For example, in
[19] a fusion of keystroke dynamics, mouse movement and
stylometry was studied. Keyboard and mouse dynamics
were also used in [20], yet this time were fused with
interface (GUI) interactions. Two types of fusion were
utilized: feature level fusion and decision level fusion.
We have also found studies in which: (1) two multi-
modal systems that combine pen/speech and mouse/key-
board modalities were evaluated [21]; and (2) fingerprint
technology and mouse dynamics were used [22]. A dif-
ferent type of mouse dynamic-related fusion was utilized in
[23]. This fusion considered only mouse movement, yet
divided it into independently classified feature clusters.
Subsequently, a score level fusion scheme was used to
make the final decision.
2.3 Eye movement biometrics
Eye movement biometrics have been studied for over 10
years [24,25] on the assumption that the way in which
people move their eyes is individual and may be used to
distinguish them from each other. Two aspects of eye
movement may be analyzed: the physiological, concerning
the way that a so-called oculomotor plant works, and the
behavioral, which focuses on the brain activity that forces
eye movement. Therefore, plenty of possible experiments
may be utilized.
The most popular experiments focus just on forcing eye
movements, as the physiological aspect seems easier to
analyze and more repeatable. The simplest example of such
an experiment is a so-called jumping point stimulus. Dur-
ing such a scenario, users must follow with their eyes a
point displayed on a screen periodically changing position
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[24,26,27]. Studies with this kind of stimulus mostly
measure physiological aspects, as subjects are instructed
where to look and cannot make this decision
The other popular type of experiment is recording eye
movement while users are looking at a static image
[25,28,29]. The content of the image may differ, but the
most popular content so far is images with human faces.
This results from the conviction that the way in which faces
are observed is different for everyone [28,30,31]. A
changing scene (movie) is the other possible stimulus
Another kind of experiment is recording eye movement
while users fulfill some specific visual tasks. This seems to
be a promising scenario; however, there are only a few
research papers published so far including text reading
[34], following with eyes more complex patterns [35] and
normal activity like reading and sending emails [36].
When eye movement recordings are gathered, the next
problem is how to extract attributes that may be usable for
human identification. Various approaches have been pro-
posed, one of the most popular of which involves the
extraction of fixations (moments when an eye is relatively
still to enable the brain to acquire a part of an image) and
saccades (rapid movement from one fixation to another)
and performing different statistical analyses on them.
Simple statistics may be applied [3739] or more sophis-
ticated, like comparisons of distributions used [40]. In ref.
[26], an interesting attempt to use eye movement data to
build a mathematical model of the oculomotor plant has
also been presented. Other approaches analyze the eye
movement signal using well-known transformations like
Fourier, wavelet or cepstrum [24,41,42]. There are also
some methods that take spatial positions of gaze data into
account to build and then analyze heat maps or scan paths
The results obtained in all the aforementioned experi-
ments are far from ideal. Additionally, it is difficult to
compare results of various experiments because scenarios,
hardware (i.e., eye tracker) and participants vary between
them all. Unfortunately, authors are reluctant to publish
their data, which would enable future comparisons. A
notable exception is the EMBD database (http://cs.txstate.
edu/*ok11/embd_v2.html) published by Texas State
University and databases used in publicly accessible Eye
Movement Verification and Identification Competitions:
EMVIC 2012 [27] and EMVIC 2014 [31].
Although it seems natural that the eye movement
modality may be combined with other modalities, to the
best of our knowledge there have been only two attempts to
provide eye movement biometrics in fusion with another
modality. In ref. [43], eye movements were combined with
keystroke dynamics, but the results showed that errors for
eye movements were very high and the improvement when
fusing both keystroke and eye movements was not signif-
icant. In ref. [44], eye movement biometrics were fused
with iris recognition using low-quality images recorded
with a cheap web camera.
2.4 Paper’s contribution
The analysis of the existing methods used for biometric
identification in both previously described areas encour-
aged the authors to undertake studies aimed at com-
pounding signals of eye and mouse movement in a user
authentication process. There are several reasons that such
studies are worth undertaking. Both signals stem from
human behavioral features, which are difficult to forge.
Their collection is easy and convenient for users, who
naturally use their eyes and a mouse to perform computer-
related tasks. Furthermore, the devices that acquire these
signals are simple and cheap, especially when built-in web
cameras are used, and can be easily incorporated in any
environment by installing the appropriate software. The
important feature of the considered solution is also the fact
that both signals can be registered simultaneously, which
makes data collection quicker. Additionally, if necessary,
the method may also be used for covert authentication.
A novel type of experiment that was based on entering a
PIN was designed for this purpose.
Data obtained from both eye and mouse movements
were processed to construct dissimilarity matrices [2] that
would provide a set of samples for training and testing
phases of a classification process. A similar approach was
used in [17] for mouse dynamics; however, it has never
been applied for eye movement data. Taking the above into
consideration, the research contribution may be listed as
Introduces a new idea for biometric identification based
on fusion of eye and mouse movements that reduces
identity verification time and improves security.
Elaborates a new experiment type which can be easily
applied in many environments.
Applies a dissimilarity space using dynamic time
warping for extraction of features from eye movement
and mouse dynamics.
3 Experiment
This section describes the environment used for conducting
experiments. The test scenario and some quantitative
information about the data analyzed are presented.
Pattern Anal Applic (2018) 21:91–103 93
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3.1 Scenario
All data were gathered with one experimental setup con-
sisting of a workstation system equipped with an optical
mouse and the Eye Tribe ( system for
recording eye movement signal at sampling rate of 30 Hz
and an accuracy error of less than 1. It is worth mentioning
that this eye tracker is affordable ($100) and convenient to
use, unlike most of the eye trackers used in the previous
research of eye movement biometrics. The eye tracker was
placed below a screen of size 30 50 cm. The users sat
centrally at a distance of 60 cm. Three such systems were
used simultaneously during the data collection phase. The
low frequency usage was motivated by the idea of checking
whether valuable data may be obtained even for frequencies
available to commonly used web cameras. Additionally,
mouse movements were recorded with the same frequency.
All tests were conducted in the same room. At the
beginning of each session, participants signed a consent
form and were informed about the purpose of the experi-
ment. Each session for each participant started with a
calibration process ensuring adjustment of an eye tracker to
the eye movement of the particular user. Users were asked
to follow a point on the screen with their eyes. After nine
locations, the eye tracker system was able to build a cali-
bration function and measure a calibration error. Only users
obtaining a calibration error value below 1were allowed
to continue the experiment.
In the next step, circles with 10 digits (0–9) were evenly
distributed over the screen, displayed (Fig. 1). The partic-
ipant’s task was to click these circles with the mouse to
enter a PIN number. The PIN was defined as a four-digit
sequence, for which every two consecutive digits were
always different. Both mouse positions and eye gaze
positions were recorded during this activity. It was
assumed that people look where they click with the mouse;
therefore, eye and mouse positions should follow more or
less the same path. One such recording of a PIN being
entered is called a trial in subsequent sections. A trial is a
completed task of entering one PIN, during which eye and
mouse movements were registered. To make simulation of
a genuine–impostor behavior possible, all participants
entered the same PIN sequence: 1–2–8–6.
There were several sessions with at least a 1-week
interval between sessions. During each session, the task
was to enter the same PIN three times in a row.
3.2 Collections used
A total of 32 participants took part in the experiments, and 387
trials were collected. As each user entered the PIN three times
during one experiment, the trials were grouped into sessions.
Each user’s session consisted of three subsequent trials. The
gathered trials were used toprepare three collections differing
in the number of sessions registered for one user:
C4—24 users, four sessions per user, each containing
three trials,
C3—28 users, three sessions per user, each containing
three trials,
C2—32 users, two sessions per user, each containing
three trials.
4 Methods
The data gathered in the described experiment were then
processed to obtain information about people’s identity.
The process was divided into several phases:
Preparation phase—when every trial was processed to
extract different signals,
Feature extraction phase—when a sample was built on
the basis of features derived from signals (there are
three different approaches presented below),
Training phase—when samples with known identity
were used to build a classification model,
Testing phase—when the model was used to classify
samples with unknown identity,
Evaluation phase—when the results of the testing phase
were analyzed.
This section describes all these steps in detail.
4.1 Preparation phase
The aim of the preparation phase was to separate different
signals from eye and mouse movements recorded during
the experiments. A signal is defined as a characteristic
feature that can be extracted from each trial. This analysis
concerned only parts of recordings collected between the
first and fourth mouse click.
Fig. 1 Example view of a screen with eye movement fixations
mapped to the chosen digits
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As a result, 24 separate signals were calculated: 11
signals for mouse, 11 signals for gaze and two additional
signals representing mouse and eye position differences
(Table 1). Depending on the length of the recording, each
signal consisted of 105–428 values (from 5 to 21 s).
4.2 Feature extraction phase
The second step in the authentication process was to define
a set of samples that could be used as input for a classifier.
The input for this phase was the fusion of 24 mouse and
eye signals prepared for each trial earlier.
Three different feature extraction algorithms were used:
Statistic values
Distance matrix
The detailed description of each is presented in the fol-
lowing sections.
4.2.1 Features based on statistic values
The first of the applied methods is commonly used in many
studies [13,16,18]. It is based on statistical calculations
relating to previously extracted signals. For each, four
statistics were calculated independently for each trial: min,
max, avg, stdev. A sample in this method was defined as a
vector including statistics for all signals from one trial. As
the total number of signals was 24, a vector consisted of
24 4¼96 attributes (Fig. 2).
4.2.2 Histograms
In the second of the feature extraction methods, a sample is
represented by histograms built for each signal and eval-
uated for each trial separately. The frequencies of values
occurring in histogram bins were stored as sample attri-
butes. Because various numbers of bins (B) were consid-
ered—B10;20;30;40;50Þ—a sample for one trial
consisted of 24 Battributes.
4.2.3 Distance matrix
In the last of the developed methods, the feature extraction
process was based on an evaluation of distances between
all training trials. While constructing relevant data struc-
tures, the signal-based description of a trial was taken into
account. Therefore, each signal (for instance x, vx, y, vy)
was treated individually and was used to build an inde-
pendent distance matrix. Let us recall that 24 signals were
Table 1 Set of signals extracted from eye and mouse movements
Signal Formula Description
x, y Xand YThe raw coordinates
vx, vy Vx¼ox
otThe first derivative of Xand Y(i.e., vertical and horizontal velocities)
vxy V¼ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi
qThe first derivative for absolute velocity
ax, ay V0
otThe second derivative of Xand Y(i.e., vertical and horizontal accelerations)
axy V0¼ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi
qThe derivative of vxy
jx, jy V00
The third derivative of Xand Y(jerk)
jxy V00 ¼ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi
qThe derivative of axy
Diffmgx xmouse xgaze The difference between mouse and gaze positions—axis x
Diffmgy ymouse ygaze The difference between mouse and gaze positions—axis y
Fig. 2 Diagram of the statistic-
based feature extraction
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determined in the preparation phase; thus, 24 distance
matrices were built. Further, for Ntraining trials, a matrix
consisting of Nrows and Ncolumns (NNcells) was
obtained to define distances for all training trials (Fig. 3).
Various metrics may be used when comparing distances
of two signals. Euclidean is most common, based on the
sum of all differences for every value registered for a
signal. However, the Euclidean metric is not robust when
comparing shapes of signals, which are shifted in time.
Therefore, it was decided to use a nonlinear dynamic time
warping distance metric for signal comparisons [45]. The
DTW algorithm first calculates distances between all val-
ues in both signals and then searches for a sequence of
point pairs (called the warping path) that minimizes the
warping cost (sum of all distances) and satisfies boundary,
continuity and monotonicity conditions [46]. The distance
for each signal was calculated as the sum of distances
between point pairs on the warping path (see Eq. 1).
DTW Tsignal
where w0wKis a warping path consisting of K points
with (i,j) coordinates and
The DTW algorithm applied for two signals from two dif-
ferent trials Tiand Tjprovided one value representing their
distance Dsignal
ij . This value became an element of a distance
vector forming a sample of the analyzed signal. A similar
attempt limited to mouse dynamics signal was used in [17].
Dsignal ¼
D11  D1N
DN1 DNN
;signal 2124 ð3Þ
For classification purposes, every column of such a matrix
was treated as one feature. The rows of the matrices were
then used as training samples to train classifiers. The same
procedure was then repeated for every testing sample,
whose distances to all N training samples were calculated
and used as Nfeatures of that sample. The distances were
calculated for each of 24 signals forming 24 matrices.
4.3 Training and testing phase
At the end of the feature extraction phase, several sets of
samples were collected:
1. One set with statistic values as features—stat,
2. Five sets with histograms for 10, 20, 30, 40 and 50 bins
as features—histbin,
3. 24 sets with DTW distances as features—one for each
signal type—matrixsignal.
All these sets were built separately for all collections of
trials (C2, C3 and C4) described in Sect. 3.2. Each set,
divided into Ntraining and Mtesting samples, was then
evaluated using the cross-validation method (Table 2). It is
very important to emphasize that the division into training
and testing sets was not random. Consecutively collected
trials tend to be more similar to each other than trials
collected after longer intervals; therefore, due to the short-
term learning effect [47], including them in both training
and testing sets may produce improperly obtained better
accuracy results. Hence, the general rule was not to use
trials of the same user gathered in the same session for both
Fig. 3 Diagram of the feature
extraction algorithm based on a
distance matrix
Table 2 Number of training and testing samples for each collection
Collection Samples per
Training samples
Testing samples
C4 12 216 72
C3 9 168 84
C2 6 96 96
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training and testing purpose. Detailed analysis of this
phenomenon can be found in Sect. 5.2.
Building a rule according to which a fold was related to
one session was a motivating factor. Therefore, collection
C4 was divided into fourfold representing four sessions. As
a result, all samples of one user from the same session were
always in the same fold and were used together as either
training or testing samples. A similar procedure was
applied for C3 and C2 collections, dividing them into three
and twofold, respectively. For such a folding strategy, a
testing set always contained three trials of each user
recorded during the same session (one by one).
A classification model was built based on N training
samples, with usage of an SVM classifier [48]. Using data
of a similar structure utilized in our previous research [49]
and a grid search algorithm, we obtained the best results for
the RBF kernel with gamma ¼29and C¼215. There-
fore, these values were used in the current research. The
sequential minimal optimization algorithm was used [50]
with the multiclass problem solved using pairwise coupling
[51]. The classification model was then used for classifi-
cation of Mtesting samples. For each of them, the classifier
returned a vector of probability values that a given sample
belongs to a particular user. If the number of users is
denoted by U, for every testing sample we obtain a U
element vector representing distribution of probabilities for
each of Upossible classes. A set of such Mvectors (for all
testing samples) forms a matrix of size MU.
Initially, during the testing phase, all trials in a testing set
were classified separately giving independent distributions
for each trial a: Ptriala. These distributions were subse-
quently summed up and normalized for trials related to the
same session (let us recall that there were three trials for one
session). Having probability vectors of three trials (a, b and c)
of the same user gathered during the same session, the
probability vector for the session was calculated as:
where set represents the set of samples used. Such a
probability vector was the outcome of the method using the
statistic features. However, an additional step was designed
for histbin and matrixsignal types as both corresponding
methods for the feature extraction define more than one set.
The histogram method provided different sets for a par-
ticular number of bins (10, 20, 30, 40 and 50)—altogether
five sets—whereas in the distance matrix approach we
obtained 24 sets, each for one signal. Hence, the result in
these cases was determined as a sum calculated for all bins
or signals sets. The vector of probability distribution, after
the last step, included values as those presented in Eq. 5,
where Xrepresented the number of sets used (a number of
bins or a number of signals, 5 or 24, respectively).
The result of this step was three probability distributions:
One for statistic values.
One for histogram values (normalized sum of results
for five histograms).
One for distance matrix values (normalized sum of
results for matrices built for 24 signals).
These three distributions were then used in the subsequent
evaluation step to check their correctness. It should be
emphasized that in the process of the probability distribu-
tion evaluation, a fusion of features characterizing eye
movement and mouse dynamic was applied.
4.4 Evaluation phase
The last step of the classification process was to assess the
quality of models developed in the previous phases. The
result of the testing phase was probability distributions for
every possible class U (user identity). As was explained in
the previous section, distributions were calculated using
three trials from one session so the number of distributions
was S¼M=3, where Mwas the number of testing trials.
The result was a matrix P:½SU, where each element pi;j
represented the probability that the ith testing sample
belongs to user j.
In the evaluation phase, this matrix was used to calculate
accuracy (ACC), false acceptance rate (FAR) and false
rejection rate (FRR) for different rejection threshold th
values and finally to estimate equal error rate (EER) for
every collection and feature extraction method.
At first, the correctness of the classification c(i) for
every ith distribution on the basis of its correct class u(i)
was calculated as:
cðiÞ¼ 1pi;uðiÞ¼maxðpi;1...pi;uÞ
0 otherwise
Then, the accuracy of the classification for the whole
testing set was calculated:
accuracy ¼PS
The next step was calculation of acceptance ai;jfor dif-
ferent thresholds th. The value of thresholds ranged from 0
to 1.
ai;jðthÞ¼ 1pi;j[th
0 otherwise
Based on this acceptance, it was possible to calculate FAR
and FRR for different thresholds.
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It can be easily predicted that all samples were accepted for
a rejection threshold th = 0; thus, FRR = 0 and FAR = 1.
When increasing the threshold, fewer samples were
accepted, hence FRR increased and FAR decreased. For th
= 1, no samples were accepted, consequently FRR = 1 and
FAR = 0. FAR and FRR dependency on rejection threshold
value is presented in Fig. 4.
Equal error rate (EER) was calculated for the rejection
threshold value for which FAR and FRR were equal (as
visible in Fig. 4).
5 Results
Feature extraction methods used in training and testing
phases and as presented in Sect. 4.2 were independently
evaluated for each collection of trials: C4, C3 and C2. As
was described earlier, they differed in the number of
recorded sessions, which amounted 4, 3 and 2 sessions
accordingly, whereas one session consisted of 3 trials. At
the end of the classification process, two values were
reported for each collection and each type of features (stat,
hist, matrix). These were Accuracy and ERR, calculated
according to methods described in evaluation phase sec-
tion. The results are presented in Table 3.
The best result was obtained for collection C4, when the
matrix type that was based on the fusion of distances of eye
and mouse features was applied. In this case, 4 different
sessions were available for each subject and the classifi-
cation model was trained using three of them each time (12
trials compared to 9 in C3 and 6 in C2). The hist type was
the best option also for collection C3, while the statistic
method gave the lowest errors for C2. However, the results
for collections C3 and C2 were significantly worse. The
ERR value was 31.15 % (C2 collection and a stat set),
which cannot be treated as a good outcome, especially as it
was not significantly better than other ERR values for this
collection. The probable reason of such findings was the
fact that to build a training model for each user, less data
were available (only two and one session accordingly).
The DET curves presenting the dependency of FRR and
FAR ratios are shown in Fig. 5.
5.1 Comparison of mouse and gaze
The next research question was to check whether a fusion
of gaze and mouse biometrics gives results better than a
single modality. For this purpose, two additional experi-
ments for the C4 dataset were performed: one using only
mouse-related signals and one using only gaze-related
signals. Both concerned only the matrix method, which
yielded the best outcomes in the previous tests. Table 4
presents a comparison of these results to the fusion of both
The row denoted by ‘‘Gaze’’ corresponds to the effi-
ciency of the algorithm when only 11 signals derived from
eye movement were taken into account. The same regards
the ‘‘Mouse’’ row, which shows results for 11 signals
derived from mouse-related signals. The results presented
in the ‘‘Fusion’’ row are calculated on the basis of all 24
signals (11 mouse ?11 gaze related ?2 based on mouse–
gaze differences). All these outcomes revealed that mouse
dynamics gave better accuracy and lower errors than eye
movements. Most importantly, the fusion of mouse and
gaze gave results significantly better than both modalities
Fig. 4 Chart showing how FRR and FAR depend on the value of the
rejection threshold
Table 3 Results of identification (Accuracy) and verification (EER)
for different collections and sets
Collection Set Accuracy (%) EER (%)
C2 Stat 25.00 31.15
C2 Hist 21.88 34.78
C2 Matrix 15.62 34.59
C3 Stat 32.14 21.28
C3 Hist 32.14 20.68
C3 Matrix 46.43 16.78
C4 Stat 28.57 20.30
C4 Hist 57.14 10.32
C4 Matrix 92.86 6.82
98 Pattern Anal Applic (2018) 21:91–103
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5.2 Examining the learning effect
The learning effect is a phenomenon characteristic of
biometric modalities that measures changes of human
behavior over time [47]. It is sometimes treated as a kind of
well-known template aging problem, but its nature is
slightly different. While template aging is related to bio-
metric template changes over a long time (e.g., a face gets
older), the learning effect addresses short time changes in
human behavior. It is obvious that a tired or sad person
reacts differently than a rested and relaxed one. Various
beverages and food such as coffee or alcohol may also
influence people’s behavior. For this reason, it is very
important to register behavioral biometric templates with
some considerable time interval to avoid short-term simi-
larities and extract truly repeatable features. This phe-
nomenon has already been studied for eye movement, and
the results showed that eye movement samples collected at
intervals of less than 10 min are much more similar to each
other than samples collected at 1-week interval [52].
During the tests described in Sect. 4, we tried to avoid
this problem by the appropriate preparation of training and
testing folds of samples. We ensured that during the cross-
validation, samples related to a user’s session were never
split into two folds (see Sect. 4.3) and the time interval
between two sessions of the same user was never shorter
than 1 week. We called this folding strategy ‘session-
based folding,’’ as data for the whole session was always in
either a training or testing set.
However, we decided to raise the research question to
check whether mixing samples derived from one session in
training and testing sets did indeed result in better classi-
fication performance. Therefore, the additional cross-vali-
dation experiment was performed with a different fold
preparation strategy. As there were always three trials in
Fig. 5 DET curves for different feature extraction methods and collections C2, C3 and C4, respectively
Table 4 Results achieved for the matrix method for collection C4 for
different subsets of signals
Set Accuracy (%) EER (%)
Fusion 92.86 6.82
Gaze 64.29 16.79
Mouse 78.57 9.05
Pattern Anal Applic (2018) 21:91–103 99
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
each session, this time every set was divided into three
folds: The first trial of the session was in fold 1, the second
attempt in fold 2 and the third one in fold 3. We called this
folding strategy ‘‘mixed sessions folding,’’ as this time
trials from the same session were always divided into
separate folds.
Using such folds for cross-validation ensured that there
was always a sample of the same user from the same
session in both training and testing sets. The classification
results are compared to the previous ones and presented in
Table 5.
As could be expected, the accuracy for modified folds
was higher and errors were lower because it was easier for
the classifier to classify a trial with two other trials from the
same session (i.e., very similar). The errors were lower for
both modalities, but the difference for gaze-based bio-
metrics was more significant. As given in Table 5, accuracy
for the gaze was even better than for the mouse. Accuracy
for the fusion reached 100 % because the correct class had
the highest probability for every sample, but EER was not
0 % because it was not possible to find one threshold that
worked perfectly for every sample distribution. If a
threshold perfectly separated probabilities of genuine and
impostor classes for one sample, the same threshold did not
work perfectly for other samples.
6 Discussion
At the beginning of our research, we raised some research
questions that were answered one by one during consecu-
tive experiments. Our primary objective was to examine
the possibility of fusing eye and mouse characteristics to
define a robust authentication model. Accuracy of 92.86 %
and EER of 6.82 % seem to be very good results compared
to previous studies concerning both modalities indepen-
dently. Other advantage of our approach is the develop-
ment of an identification/verification scenario that is very
convenient for users and—very importantly compared to
other research in this field—it takes on average only 20 s to
collect biometric data. It must be mentioned that some
authors of mouse-related research reported lower error
rates, but these results were achieved for longer mouse
recordings, e.g., 2.46 % EER for 17 min of a signal reg-
istration in [14]. Recordings with comparable time yielded
results worse or comparable to ours, yet usually much more
training data were required. An extended comparison of
our method to others found in the literature is presented in
Table 6.
A similar analysis may be provided that considers the
second modality. The results obtained in our studies for
eye-movement-related biometrics are comparable in
performance to recent achievements. Yet, it is once
again important to emphasize that our experiments
required significantly shorter registration time. Another
advantage of our method is that results were achieved
for a very low frequency of eye movement recordings.
Obviously, a frequency of 30 Hz gives less data for
analysis; however, its advantage is that it can register
eye movements with classic low frequency web cam-
eras, which are built-in components of many computer
Broader summary of results published since 2012 is
found in Table 7.
On the basis of these comparisons, we may deduce that
our feature extraction method based on the fusion of dis-
tance matrices gives very good results, even when much
less data are available compared to previous research. On
the other hand, fusing eye movement with mouse dynamics
allows for further improvement of the overall results of the
whole biometric system. Deeper analysis of the results
reveals other important findings.
Table 5 Results achieved for the matrix method for collection C4 for
mixed session folding
Set Accuracy (%) EER (%)
Fusion 100 2.94
Gaze 92.86 9.37
Mouse 85.71 5.04
Table 6 Comparison of
outcomes of different mouse-
related research and the results
presented in this paper
References Testing sample duration (s) Equal error rate Training samples duration (s)
Gamboa et al. [13] 50 s (200 s) 2 % (0.2 %) 200 s
Hashiaa et al. [16] 20 s 15–20 % [HTERa] 400 s
Zheng et al. [15] 100 s–37 min 1.3 % 166 min–60 h
Feher et al. [18] 42 s (139 s) 10 % (7.5 %) n/a (15 h per user)
Shen et al. [17] 12 s 8.35 % [HTERa] 885 s
Our result (mouse) 20 s 9.05 % 60 s
Our result (fusion) 20 s 6.82 % 60 s
aHTER—half total error rate—(FAR?FRR)/2 for some threshold
100 Pattern Anal Applic (2018) 21:91–103
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(1) We discovered that a modality based on mouse
dynamics outperforms one based on eye movement;
yet, more importantly, a fusion of both characteris-
tics gives the best results.
(2) The conducted experiments were based on three
different feature extraction strategies. The distance
matrix-based feature extraction method outperforms
traditional methods based on statistics and his-
tograms with ERR of 6.82, 10.32, 20.30 %,
(3) Tests considering several collections with different
numbers of trials, with the best results for those
consisting of 3 training and 1 testing sessions (C4),
showed that slightly increasing the number of
training samples influences performance
(4) Last but not least of the findings, related to the
learning effect, confirmed the importance of correct
evaluation phase planning, which is especially
remarkable when cross-validation is used, as an
incorrect and unfair folding strategy may easily lead
to a model overfitting.
7 Summary
The research presented in this paper aimed to find a new
method for behavioral biometrics. The main objective of the
studies was to find a solution characterized with a relatively
short identity verification time and a low level of classifi-
cation errors. The results obtained during experiments con-
firmed that the objective was achieved. The paper showed
that the fusion of the mouse dynamics and eye movement
modalities may be used for this purpose. Furthermore, it
proved that such a fusion may be achieved in one experiment
that is both short and convenient for participants.
The novel feature extraction method, which was based
on fusion of distance matrices, yielded results comparable
or better than those previously published for both single
modalities. The algorithm applied in the method makes it
useful for any kind of modality fusion.
It is also worth mentioning that despite the 6 % error
rate, our method may be used in practical applications as a
part of a verification system. Participants of our experiment
entered a 4-digit PIN by clicking digits in the correct order
with a mouse. Because we were interested in the compar-
ison of eye and mouse movements only, all participants
entered the same PIN (namely the sequence 1–2–6–8).
However, in a real-life environment knowledge of a PIN
could be the first stage of verification. If a participant
entered the proper PIN, our algorithm would be activated
to check whether the participant’s identity claim was
genuine. The proper setting of the rejection threshold could
lower false rejections, as it is unlikely that an impostor
knows the PIN number and has similar mouse and eye
movement dynamics that characterize a genuine user.
To conclude the presented studies, we will summarize
the most important contributions of the paper:
1. The proposed feature extraction method using the
fusion of distance matrices gave results (92.86 %
accuracy and 6.82 % Equal Error Rate) which are
competitive compared to those already published in
this field, while less data were used for both training
and testing phases (about 60 and 20 s, accordingly).
This is the case for both eye movement and mouse
2. The paper showed that the fusion of the mouse
dynamics and eye movement modalities can be done
in one experiment which is both short and convenient
for participants.
3. We showed that the fusion of these two modalities may
lead to better results than for each single modality.
4. It was shown that eye movement data recorded with a
low frequency (30 Hz) may give information sufficient
to achieve equal error rates (16.79 %) comparable to
the state-of-the-art results.
Additionally, it should be noticed that the setup of the
experiment is not complicated and may be reconstructed
Table 7 Comparison of
different gaze-related research
with the results presented in this
References Testing sample duration (s) Equal error rate (%) Recording frequency
Komogortsev et al. [53] 100 s 16 % 1000 Hz
Holland et al. [40] 60 s 16.5 % 1000 Hz
Holland et al. [40] 60 s 25.6 % 75 Hz
Rigas et al. [33] 60 s 12.1 % 1000 Hz
Cantoni et al. [30] 160 s 22.4 % 50 Hz
Tripathi et al [38] 60 s 37 % 1000 Hz
Our result (gaze) 20 s 16.79 % 30 Hz
Our result (fusion) 20 s 6.82 % 30 Hz
Pattern Anal Applic (2018) 21:91–103 101
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easily. The only hardware requirements are a computer
equipped with a mouse and an eye tracker. The research
described in the paper showed that the frequency of com-
monly used webcams may provide satisfactory results. The
appropriate software (e.g., ITU Gaze Tracker) could be
used in this case. Another affordable solution is a low-cost
remote eye tracer, like that used in the experiments (i.e.,
Eye Tribe).
7.1 Future work
When designing our research, we decided to involve the
fusion technique on the decision level for the distance
matrix method and on the feature level for the statistic one
[3]. The next planned step is to extend all methods to
involve fusion on various levels. For this purpose, various
feature selection methods are also planned to be taken into
Additionally, we plan to conduct the same experiments
for more participants. Data were collected for 32 participants
used during the experiment. Such a pool of data seem to be
enough to draw some meaningful conclusions; however, a
much larger pool is necessary to confirm our findings.
Moreover, our experiments showed that a higher number of
training samples guarantees better classification perfor-
mance. Therefore, it may be expected that more than three
training samples (as was for our best collection) should
improve the results. Five to six sessions are planned for each
participant. With more data to analyze, it would be possible
to calculate weights for each of the elements of the fusion.
Weighted fusion would probably give even better results.
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appropriate credit to the original author(s) and the source, provide a
link to the Creative Commons license, and indicate if changes were
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... Even if a direct comparison among methods is rather difficult, due to the many different experimental conditions (such as eye tracker's frequency, number of participants, type and duration of stimuli, performance metrics, etc.), some general considerations can be made from the observation of Table XIV. First of all, apart from [19], [20], and [24], these works achieved their results by concentrating the data into global datasets rather than exploiting the data obtained in temporally separated sessions (e.g., leave-one-out was used in [30], random split in [17], and cross validation in [23], [34], and [36]). Also, high-frequency (and thus expensive) eye trackers were often employed. ...
... Also, high-frequency (and thus expensive) eye trackers were often employed. Another important aspect is calibration (required in [19], [20], [23], [25], [30], [34], [36], and [38]), which may make an authentication procedure longer and potentially annoying for the user -on the contrary, our approach does not require any kind of calibration of the eye tracker. Sometimes, the user was constrained in their movements (e.g., with a chin rest in [38] and with a wearable device in [30]), which would be impracticable in real authentication settings. ...
The recent COVID-19 outbreak has highlighted the importance of contactless authentication methods, such as those based on eye or gaze features. These techniques have the advantage that they can also be used by people wearing mouth and nose masks, which would make traditional face recognition approaches difficult to apply. Moreover, they can be used in addition to traditional authentication solutions, such as those based on passwords or PINs. In this work, we propose a study on gaze-based soft biometrics exploiting simple animations as visual stimuli. Specifically, we consider four animations in which small squares move according to different patterns and trajectories. No preliminary calibration of the eye tracking device is required. The collected data were analyzed using machine learning algorithms for both identification and verification tasks. The obtained results are particularly interesting in the verification case, that is the natural application of a soft biometric system, with accuracy scores always higher than 80% and Equal Error Rate (EER) values often lower than 10%.
... Much of the existing work in mouse dynamics is on multimodal authentication systems but keystroke dynamics are most often clubbed with mouse dynamics. It is suggested that better performance may be attained when the mouse dynamics are clubbed with non-behavioural modalities like eye movement (Kasprowski and Harezlak 2018). Mouse dynamics have the potential to frame user authentication and to create adversarial mouse trajectories as same as characteristic features leveraged in authentication systems . ...
... Rights reserved. Kasprowski and Harezlak (2018) Eye moving and mouse dynamics frame The projected scheme has gained better exactness measure and less error rate ...
Full-text available
Authentication is the process of keeping the user’s personal information as confidential in digital applications. Moreover, the user authentication process in the digital platform is employed to verify the own users by some authentication methods like biometrics, voice recognition, and so on. Traditionally, a one-time login based credential verification method was utilized for user authentication. Recently, several new approaches were proposed to enhance the user authentication framework but those approaches have been found inconsistent during the authentication execution process. Hence, the main motive of this review article is to analyze the advantage and disadvantages of authentication systems such as voice recognition, keystroke, and mouse dynamics. These authentication models are evaluated in a continuous non-user authentication environment and their results have been presented in way of tabular and graphical representation. Also, the common merits and demerits of the discussed authentication systems are broadly explained discussion section. Henceforth, this study will help the researchers to adopt the best suitable method at each stage to build an authentication framework for non-intrusive active authentication.
... Ceramic products have a long history, and people started making ceramic products long ago, which are not only practical but also highly artistic and ornamental [1]. The Chinese ceramic industry has a long and illustrious history, with pottery appearing in China some 5,000 years ago, and early porcelain in the middle of the Shang Dynasty, and in the Ming and Qing Dynasties, ceramic products were exported overseas, spreading and promoting the traditional culture of the Chinese nation. ...
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Ceramic product shape evaluation is an important part of product development, an important method to optimize product shape design, and is of great significance to reasonably locate users’ consumption psychology and promote the development of ceramic product industry. In this paper, we propose an eye-tracking-based evaluation method for ceramic products from the user’s point of view, in view of the fact that there are few studies on ceramic product shape evaluation, and it is mainly led by designers and enterprise leaders subjectively, with low user participation and lack of objective evaluation means and objective data support. In this paper, through the implementation of eye-movement experiments, we obtain and analyze the eye-movement data related to the semantic perception evaluation of product modeling and the overall evaluation of modeling, establish the mapping relationship between user evaluation and eye-movement data, and provide objective data support for modeling evaluation. This paper provides an objective data support for the styling evaluation. This paper provides new ideas for the ceramic product modeling evaluation method, which helps to promote the development of ceramic product industry, improve the brand recognition of enterprises, and help the marketing personnel to make reasonable marketing planning plans. For the semantic perceptual evaluation of ceramic product styling based on eye-tracking, the effectiveness of product styling design concept communication is evaluated. Ceramic products are constantly changing and developing, with new shapes appearing and old shapes being eliminated. Continual innovation and development of ceramics based on inherited traditions can give them a new look and color under the existing modeling style. Compared with other categories, although ceramic modeling has relatively abstract formal characteristics, but it is the extension of the modeling, still has obvious morphological characteristics, and the impact on people’s aesthetic mood. 1. Introduction Ceramic products have a long history, and people started making ceramic products long ago, which are not only practical but also highly artistic and ornamental [1]. The Chinese ceramic industry has a long and illustrious history, with pottery appearing in China some 5,000 years ago, and early porcelain in the middle of the Shang Dynasty, and in the Ming and Qing Dynasties, ceramic products were exported overseas, spreading and promoting the traditional culture of the Chinese nation. Since China’s reform and opening up, the ceramic industry has developed rapidly. In order to further enhance the industry, China has introduced advanced technology to the ceramic industry and made the products have better market satisfaction by continuously improving firing technology and other ways [2]. In addition, on the original technology, China also innovated the relevant processes and gave a lot of new colors in terms of creativity and design, and now, China produces a large number of ceramic products every year and has become the world’s largest ceramic producer. With the development of social and economic development and living conditions, user needs have also increased. According to Maslow’s pyramid of needs, people in the case of meeting the needs of the bottom gradually expect the satisfaction of the needs of the top [3]. The same applies to the field of products, when the user’s bottom demand for products that are functional and easy to use is satisfied, users will seek to meet their needs of high-level products. Therefore, the function of ceramic products, form, structure, and its spiritual and cultural connotations needs to be updated to continue to meet the user’s product consumption needs [4]. In recent years, the ceramic industry has shown diversified and individualized market demands. The status of traditional art form as the dominant "overlord" of the typical style of ceramic products began to shake. Traditional ceramic products are facing a serious test and fierce competition [5]. In this environment, in order to meet market demand, ceramic enterprises also gradually from the “design after the function” to “design after the user.” Currently mainly by the designer’s subjective domination of ceramic product design, product characteristics are vulnerable to certain restrictions and the lack of communication with the user [6]. The shape of ceramic products is an important carrier for spreading spiritual culture and is one of the important concerns in design. Ceramic product shape evaluation is an important part of the preproduct development, an important method to optimize the product shape design, and is of great significance to reasonably position the consumer psychology of users in order to promote the development of the ceramic product industry [7]. The current ceramic modeling evaluation method needs to be improved; ceramic enterprises urgently need to ensure that the ceramic product quality is good under the premise of improving the attractiveness of ceramic product modeling, enhance brand recognition, so that it has a better competitive ability, and then make it occupy the market advantage [8]. With the change of consumer philosophy, the market demand force of Chinese ceramic products will be further expanded. In the study of the relationship between physiological behavior and user evaluation, Tang Gangbei et al. proposed a selection method based on objective eye-movement test and combined with the physiological data of EEG for the disadvantages of the current car scheme selection, using a computer to present four car design drawings for the subjects, collecting the eye-movement and EEG data when the subjects viewed the pictures, combining the subjective evaluation values of the subjects, analyzing the correlation of the three data, and establishing a multidimensional. This method improves the objectivity of car evaluation [9]. In order to objectively evaluate the car styling design, the eye-movement experiment method was used, and the hot spot map generated when the subjects observed the car pictures was used as the data source; using methods such as color feature extraction, the evaluation index system was established by collecting and processing the hot spot map information and quantifying the picture information into data; the evaluation was defined as a dichotomous problem, and the evaluation model was established using Fisher’s discriminant method [10]. They used a combination of subjective scoring method and eye-movement experiment method to collect eye-movement data and subjective evaluation data of users comparing and observing multiple pictures of car styling solutions and used partial least squares method to establish a car styling evaluation model and verify the effectiveness of the model [11]. This paper introduces eye-tracking experiments into ceramic product styling evaluation, collects several eye-movement data from subjects, and uses a combination of subjective and objective methods to obtain relevant experimental data from the evaluation activities of target users, so as to quantify the subjective evaluation of users as objective data and provide objective evaluation methods and objective data support for product styling evaluation. Improve the traditional evaluation method mainly led by designers, provide new ideas for ceramic product shape evaluation, and help promote the development of ceramic product industry. For the characteristics of user, scoring value is 0-10 integer as discrete variables; support vector machine classification method is used to establish the mapping model between eye-tracking experimental data and user scoring value, which can effectively reduce the error and improve the reliability of evaluation results. The eye-tracking technology is used to conduct the semantic perception test of ceramic product modeling, to measure the objective perception of the target users on the product design concept, to provide objective guidance for the expression of modeling design concept and product marketing promotion, to help the enterprise marketers to reasonably optimize the product promotion and marketing plan, to effectively convey the design concept, and to improve the brand recognition of the enterprise. 2. Related Work Ceramic products have a long history in China. In the early days, they were mainly daily necessities, so more attention was paid to their use function [12]. In recent years, as users’ emotional needs for products have increased, the shape of ceramic products has gradually received more attention. How to judge whether users can be attracted by the shape of the product and thus influence the purchase decision requires an effective evaluation of the shape of ceramic products from the user’s perspective [13]. They established a structural model of ceramic teaware user needs through hierarchical analysis in three directions, appearance, function, and value, used subjective questionnaires to determine the evaluation index weights, and conducted consistency tests on the obtained results, which showed that the tested user group paid more attention to the appearance of ceramic teaware; further used the fuzzy evaluation method to establish a user fuzzy comprehensive evaluation matrix, determine the evaluation criteria, and after calculating Establish a secondary comprehensive evaluation matrix to build a ceramic tea set evaluation system that quantifies the evaluation results [14]. The researchers collected and identified the perceptual vocabulary and the sample map of experimental ceramic products, created a five-order semantic scale for perceptual imagery, obtained the subjective evaluation data of the test subjects, processed the data using factor analysis to obtain the characteristic imagery factor; used the quantitative I class method, created a product morphological element coding table, quantified the morphological elements, and used multiple linear regression analysis to quantify the imagery factor and morphological element quantified values [15]. The analysis was performed by using multiple linear regression analysis to obtain the morphological factor category score and analyze the products according to this score. They summarized the advantages of the designed ceramic products from the designer’s point of view in four aspects: function, shape, aesthetics, and economy; analyzed the rationality of the product shape structure to verify its usability; analyzed the product contour lines, indicating that the lines have a sense of rhythm and undulation, and considered that the products have clear characteristics and good decorative effects [16]. However, this evaluation method is only from the designer’s point of view and lacks real user feedback evaluation. At present, there are fewer studies on the evaluation of ceramic product shape, mostly based on subjective evaluation, lacking objective evaluation methods, and objective data support and mostly from the designer’s perspective lack of real user participation in the evaluation. The concept of semantic perception comes from product semantics and cognitive psychology. Product semantics is the expression of the product’s own spiritual connotation and concept conveyed, and thus, product semantic perception is the way users perceive and understand the product’s spiritual connotation and design concept [17]. They studied and analyzed automobiles to construct a mapping relationship between users’ attention to different areas of the sample and user information, which was used as a basis for optimizing the questionnaire and thus making the analysis of the semantics of styling imagery more scientific and reasonable. The researchers analyzed the source culture, used the semantic difference method to obtain the cultural semantic words, and used the shape grammar to extract the implicit cultural elements of NRMs based on the product DNA theory to build a topologically expandable semantic model together with the explicit elements; they used the graphical thinking to convert the cultural features into graphical semantics to obtain the core NRM cultural semantic set and build a library of elements to help design activities; they used the electric vehicle charging service facility as a practical case to verify the feasibility of the method [18]. The feasibility of the method is verified. The researchers obtained user semantic-aware vocabulary from online reviews, used WordNet to filter high-frequency words, analyzed the association rules of words, used Apriori algorithm to filter words again, and built the seed feature word set from the obtained words; used neural network algorithm to train word vectors, then expanded the seed feature word set by calculating the similarity between vectors, and finally used manual annotation method to classify the words and obtain the product semantics. Finally, the lexicon is classified by manual annotation to obtain a product semantic feature lexicon. Chen et al. used the importance and similarity principles to establish a hierarchical model of porcelain vase modeling, extracted the typical features of each modeling element, and established a database of porcelain vase modeling; used cluster analysis and word frequency statistics to obtain the semantic words for porcelain vase description and then built a mapping inference library of semantic words and porcelain vase modeling; and established a user customization module system, and the system can automatically retrieve the porcelain vase modeling and generate a 3D model after the user selects the semantic words. The system can automatically retrieve the vase shape and generate the 3D model after the user selects the semantic words [19]. Early applications of eye-tracking technology were mainly used in the field of psychology, but now, it has been extended to a variety of fields including advertising, interface usability, product design, and other related fields and is becoming popular. Researchers have investigated a method to quantify the aesthetic quality of product design by applying eye-tracking technology to analyze subjects’ eye movements to predict users’ aesthetic preferences and to develop an aesthetic measurement system [20]. By using a wearable eye-tracking instrument, the researchers studied the changes of subjects’ eye gaze characteristics when observing different pictures; the experiment used two types of emotional pictures to stimulate the subjects, extracted the subjects’ gaze characteristics under each type of stimulation, and analyzed and compared the experimental results; it showed that the gaze characteristics are correlated with individual emotions, and the gaze characteristics can objectively reflect individuals’ emotions within a certain range [21]. The researchers studied the eye-movement characteristics of young women when observing advertisements and investigated whether there were differences in eye-movement behaviors among individuals; seven advertisement images were presented to 80 participants using a monitor, and the gaze information was recorded using an eye-tracking device. 3. Optimization of Ceramic Processes Combining Eye Movement and Piezoelectric Sensing 3.1. Ceramic Product Process and Mechanical Characteristics As a cultural form, ceramic art has certain peculiarities, with unique artistic charm and formal characteristics. Ceramic modeling has a distinctive cultural style and is self-contained, containing a deep artistic connotation. Ceramic modeling elements include form, texture, and color. It is not only a reflection of the basic needs of human beings in the development of civilization but also expresses the spirituality of a nation to a large extent. Human beings began to develop ceramic products from very early on; these products were at first to meet the needs of rituals or to meet the needs of people’s lives; then, people also began to pour into their own emotions in their works, according to the law of development of things let ceramics and material, spiritual, technical, and other integration, which is the wealth of human beings, but also the embodiment of human wisdom. For the overall evaluation of ceramic product styling based on eye-tracking, eye-tracking experiments are conducted with target users, and users are asked to score the satisfaction of the tested product, multiple eye-tracking data and scoring scale data of all users are collected and collated, a mapping relationship model between eye-tracking data and user scoring values is established using support vector machine, and finally, the validity of the evaluation method is verified using test set data. Based on the existence of intentions and concepts, the original material is processed to make it into a style and form with certain purposes, and to meet the different needs of culture and art is the ceramic design. The language of ceramics is relatively unique, with its own expression and modeling methods, and unlike other art categories, the language of ceramics is intuitive and does not need to be interpreted as deeply as painting and other art. For ceramic products, by embellishing them and other ways, you can create more layers of connotation from the visual aspect; this perception is not completely unconscious and not completely conscious. For static shapes, appreciating the cohesive and expansive sense of form and giving shape changes can make them show a different kind of life in space and volume, as shown in Figure 1. Ceramic products are constantly changing and developing, with new shapes appearing and old shapes being eliminated. Continual innovation and development of ceramics based on inherited traditions can give them a new look and color under the existing modeling style. In this regard, foreign scholars have pointed out that ceramics is a complex art, which has a simple form, but also needs to have a complex connotation.
... • keystroke ,mouse and screen swiping manner biometrics: These traits are more appropriate for continuous or active authentication on new mobile technologies, none of them is unique by person but they offers sufficient discriminatory information to continuously check if the user of a high risk environments keeps the same after the first login [172], [118] . ...
World has recently witnessed a surge of criminal and terrorist activities that took the lives of many innocent people. Although CCTV are becoming ubiquitous and intrusive being largely deployed to survey public and strategic areas such as airports, metro stations and shopping malls, the identification of suspects using automated methods is still a challenging task to stop further terrorist attacks or prevent crimes. Law enforcement agencies can make use of surveillance systems for the safety of our neighborhood and crime prevention or resolving. In fact, it is impossible regardless the size of manpower recruited to monitor and analyze the immense amount of CCTV footage recorded either offline or streamed at real time. The use of surveillance technology should without doubt assist to lessen the risks and number of crimes by serving as a deterrent. Biometric technologies can be a major milestone to improve the automation process of visual surveillance in order to recognize criminal offenders and track them across different places. Gait defined as the way we walk, is considered recently as a more suited modality for people recognition in surveillance scenarios. This is because it can be captured nonintrusively and covertly from a distance even with poor resolution imageries. Gait biometrics can be of benefits not only for identify recognition, but it can play a vital role to enhance the automation process for surveillance systems including reidentification and people tracking across different cameras. Moreover, a biometric signature constructed from the gait rhythmic motion pattern is considered the only likely identification method suitable for covert surveillance and reliably not prone to spoofing attacks and signature forgery. Numerous research studies haveconfirmed the potentials of using gait for people identification in surveillance and forensic scenarios, but only a few studies have investigated the contribution of motion- based features on the recognition process. we explore, in our work, the use of optical flow estimated from consecutive frames to construct a discriminative biometric signature for gait recognition. Set of different Local and global optical. flow based features have been proposed and a set of experiments are carried out using the CASIA-B dataset to assess the discriminatory potency of motion-based analyzed features for gait identification subjected to different covariate factors including clothing and carrying conditions. Further experiments are conducted to explore the effects of the dataset size, the number of frames and viewpoint on the classification process. Based on a dataset containing 1240 video sequences for 124 individuals, higher recognition rates are achieved using the KNN and neural network classifiers without incorporating static and anthropometric measurements. This confirms that gait identification using motion-based features is perceivable with acceptable recognition rates even under different covariate factors and real world environmental covariates.
... Apart from traditional machine learning-based approaches, recent studies incorporated more novel technologies, such as deep neural networks, multi-biometric fusion techniques, and different training methods. Kasprowski et al. [66] employed a fused feature analysis on mouse dynamics and eye movement biometrics for the first time, which defined a robust authentication model with the comparable result by using shorter mouse recordings. While Monda et al. [67] proposed Pairwise User Coupling (PUC) of the combination of keystroke and mouse dynamics. ...
In recent years, wearable technology is interwoven with our everyday lives because of its commoditization and comfort. Security and privacy become a big concern as many user-sensitive data have been stored in such devices, such as personal emails and bank accounts. Traditional user authentication techniques like PIN entry are unfriendly and vulnerable to shoulder surfing attacks. To address these problems, a number of new authentication methods have been proposed. In this survey, we review and categorize recent advances in user authentication for wearable devices. We classify existing studies into physiological biometrics based and behavioral biometrics based methods. For each category, we review how signal processing techniques have been used to extract features in various wearable devices. Leveraging these extracted features, specifically designed classification methods can be used to realize user authentication. Finally, we review evaluation metrics for user authentication in wearable devices. Overall, in this survey, we systematically study assorted state-of-the-art user authentication methods for wearable devices, aiming to provide guidance and directions for future research in this area.
Several studies have reported that biometric identification based on eye movement characteristics can be used for authentication. This paper provides an extensive study of user identification via eye movements across multiple datasets based on an improved version of a method originally proposed by George and Routray. We analyzed our method with respect to several factors that affect the identification accuracy, such as the type of stimulus, the Identification by Velocity-Threshold (IVT) parameters (used for segmenting the trajectories into fixation and saccades), adding new features such as higher-order derivatives of eye movements, the inclusion of blink information, template aging, age and gender. We find that three methods namely selecting optimal IVT parameters, adding higher-order derivatives features and including an additional blink classifier have a positive impact on the identification accuracy. When we combine all our methods, we are able to improve the best known accuracy over the BioEye 2015 competition dataset from 86% to 96%.
This book contains a selection of the best papers of the 33rd Benelux Conference on Artificial Intelligence, BNAIC/ BENELEARN 2021, held in Esch-sur-Alzette, Luxembourg, in November 2021. The 14 papers presented in this volume were carefully reviewed and selected from 46 regular submissions. They address various aspects of artificial intelligence such as natural language processing, agent technology, game theory, problem solving, machine learning, human-agent interaction, AI and education, and data analysis.
Plain convolutional neural networks (CNNs) have been used to achieve state-of-the-art performance in various domains in the past years, including biometric authentication via eye movements. There have been many relatively recent improvements to plain CNNs, including residual networks (ResNets) and densely connected convolutional networks (DenseNets). Although these networks primarily target image processing domains, they can be easily modified to work with time series data. We employ a DenseNet architecture for end-to-end biometric authentication via eye movements. We compare our model against the most relevant prior works including the current state-of-the-art. We find that our model achieves state-of-the-art performance for all considered training conditions and data sets.
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In recent years, user authentication based on mouse and keystroke dynamic is the most wanted topic to identify the external user and to secure information. Additionally based on the movement of the mouse and typing speed of keystroke the correct user was identified. But the problems of existing approaches are complicated data, data error, and malicious events. To overcome these threats, a novel cat recurrent neural model (CRNM) is proposed to identify the correct user and improve the accuracy rate. In this work, the CRNM approach is introduced to minimize the error rate, to detect unauthorized users by analyzing the user’s mouse and keystroke dynamic. Consequently, the trained datasets verify the inputs and identify the correct user. Thus the proposed CRNM has been implemented in the python framework, to identify the correct user. Moreover, the proposed model is validated with other existing deep learning models in terms of accuracy, false acceptance rate (FAR), F-measure, recall, false negative rate (FNR), precision, and error rate.
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The idea concerning usage of the eye movement for human identification has been known for 10 years. However, there is still lack of commonly accepted methods how to perform such identification. This paper describes the second edition of Eye Movement Verification and Identification Competition (EMVIC), which may be regarded as an attempt to provide some common basis for eye movement biometrics (EMB). The paper presents some details describing the organization of the competition, its results and formulates some conclusions for further development of EMB.
Conference Paper
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Eye movement may be regarded as a new promising modality for human computer interfaces. With the growing popularity of cheap and easy to use eye trackers, gaze data may become a popular way to enter information and to control computer interfaces. However, properly working gaze contingent interface requires intelligent methods for processing data obtained from an eye tracker. They should reflect users' intentions regardless of a quality of the signal obtained from an eye tracker. The paper presents the results of an experiment during which algorithms processing eye movement data while 4-digits PIN was entered with eyes were checked for both calibrated and non-calibrated users.
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User authentication is an important and usually final bar-rier to detect and prevent illicit access. Nonetheless it can be broken or tricked, leaving the system and its data vulnerable to abuse. In this pa-per we consider how eye tracking can enable the system to hypothesize if the user is familiar with the system he operates, or if he is an unfamiliar intruder. Based on an eye tracking experiment conducted with 12 users and various stimuli, we investigate which conditions and measures are most suited for such an intrusion detection. We model the user's gaze be-havior as a selector for information flow via the relative conditional gaze entropy. We conclude that this feature provides the most discriminative results with static and repetitive stimuli.
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This paper proposes a method for the extraction of biometric features from the spatial patterns formed by eye movements during an inspection of dynamic visual stimulus. In the suggested framework, each eye movement signal is transformed into a time-constrained decomposition by using a probabilistic representation of spatial and temporal features related to eye fixations and called fixation density map (FDM). The results for a large collection of eye movements recorded from 200 individuals indicate the best equal error rate of 10.8% and Rank-1 identification rate as high as 51%, which is a significant improvement over existing eye movement-driven biometric methods. In addition, our experiments reveal that a person recognition approach based on the FDM performs well even in cases when eye movement data are captured at lower than optimum sampling frequencies. This property is very important for the future ocular biometric systems where existing iris recognition devices could be employed to combine eye movement traits with iris information for increased security and accuracy. Considering that commercial iris recognition devices are able to implement eye image sampling usually at a relatively low rate, the ability to perform eye movement-driven biometrics at such rates is of great significance.
Conference Paper
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Growing efforts have been concentrated on the development of alternative biometric recognition strategies, the intended goal to increase the accuracy and counterfeit-resistance of existing systems without increased cost. In this paper, we propose and evaluate a novel biometric approach using three fundamentally different traits captured by the same camera sensor. Considered traits include: 1) the internal, non-visible, anatomical properties of the human eye, represented by Oculomotor Plant Characteristics (OPC); 2) the visual attention strategies employed by the brain, represented by Complex Eye Movement patterns (CEM); and, 3) the unique physical structure of the iris. Our experiments, performed using a low-cost web camera, indicate that the combined ocular traits improve the accuracy of the resulting system. As a result, the combined ocular traits have the potential to enhance the accuracy and counterfeit-resistance of existing and future biometric systems.
Conference Paper
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This paper presents an objective evaluation of the effects of stimulus type and eye tracking specifications on the accuracy of biometric verification based on complex eye movement patterns (CEM). Five stimulus types (simple, complex, cognitive, random, textual), six spatial accuracy tiers (0.5°, 1.0°, 1.5°, 2.0°, 2.5°, 3.0°), and six temporal resolution tiers (1000 Hz, 500 Hz, 250 Hz, 120 Hz, 75 Hz, 30 Hz) are evaluated to identify their effects. The results suggest the use of eye tracking equipment capable of 0.5° spatial accuracy and 250 Hz temporal resolution for biometric purposes, though biometric accuracy remains achievable for systems capable of at least 1.0° spatial accuracy and 30 Hz temporal resolution. While not conclusive, the complex and textual pattern stimuli provided the greatest accuracy, with little difference between the remaining stimuli.
Conference Paper
This paper is devoted largely for building a novel approach for human recognition using eye movement analysis. Velocity and dispersion threshold based fixation identification algorithms are employed for processing the raw scan path signals in oculo-motion matrices. A new hybrid intelligent model is deployed for classification over data retrieved from scan-path signals. Experimental results demonstrate the endeavor of oculo-motion signals as an effective biometric trait. This paper also demonstrates the relative comparison of the two fixation identification techniques combined with hybrid intelligent model.
The practice of using more than one biometric modality, sample, sensor, or algorithm to achieve recognition, commonly referred to as multi-biometrics, is a technique that is rapidly gaining popularity. By incorporating multi-biometrics into the recognition process, many of the short-comings of traditional single-biometric systems
Conference Paper
Human identification is an important task for various activities in society. In this paper, we consider the problem of human identification using eye movement information. This problem, which is usually called the eye movement identification problem, can be solved by training a multiclass classification model to predict a person's identity from his or her eye movements. In this work, we propose using Mel-frequency cepstral coefficients (MFCCs) to encode various features for the classification model. Our experiments show that using MFCCs to represent useful features such as eye position, eye difference, and eye velocity would result in a much better accuracy than using Fourier transform, cepstrum, or raw representations. We also compare various classification models for the task. From our experiments, linear-kernel SVMs achieve the best accuracy with 93.56% and 91.08% accuracy on the small and large datasets respectively. Besides, we conduct experiments to study how the movements of each eye contribute to the final classification accuracy.