Proceedings of the 2013 International Conference on Wavelet Analysis and Pattern Recognition, Tianjin, 14-17 July, 2013
JOINT IRIS AND FACIAL RECOGNITION BASED ON FEATURE FUSION
AND BIOMIMETIC PATTERN RECOGNITION
YING XU1,2, FEI LU01, YI-KUI ZHAI2 and JUN-YING GAN2
1 School of Automation, South China University of Technology, Guangzhou 510000, Guangdong, China 2 School of Information and Engineering, Wuyi University, Jiangmen 529020, Guangdong, China
E-MAIL: [email protected]@[email protected]@163.com
Abstract:
Fusion biometric recognition modal contributes in two as
pects. It can not only improve the biometric recognition accu
racy, but also gives a comparatively safe strategy, since it is dif
ficult for intruders to achieve multi-biometric information simul
taneously, especially the iris information. In this paper, a nov
el biometric fusion recognition modal with iris and facial images
based on biomimetic patteru recognition is proposed. The Con
tourlet transform (CT) and two directional two dimensional prin
cipal component analysis (2D)2PCA are used here to extract the
iris feature and the facial feature respectively, and a new fusion
feature vector was formed on the combination of the previous iris
and facial features. Lastly, the fusion feature vector is used to
construct the covering of high dimensional space using biomimet
ic patteru recognition method, in which the hyper-sausage neu
ron is adopted. Furthermore, a fixed random matrix is used here
to reduce the computational complexity and improve the recogni
tion efficiency. Experiments on the public union database show
that the proposed modal can achieve the state-of-the-art recog
nition accuracy while keeping the enrollment process safe.
Keywords:
Multi-modal biometric; Contourlet transform; (2D)2PCA;
Feature fusion
978-1-4799-0417-4/13/$31.00 ©2013 IEEE
1. Introduction
With the rapid development of the biometric recognition
technology, more and more multi-modal biometric recognition
systems [1] have been proposed for the following triple reason
s. Firstly, multi-modal biometric recognition techniques use
multi-source features, such as iris, face, finger print, palm, and
voice etc together in order to obtain integrated information of
the same object more essentially; secondly, it can improve the
recognition accuracy since it can fully utilize and fusing the
correlation information from different biometric images; Third
ly, it also gives a relatively safe strategy compare with the sin
gle biometric recognition, for single biometric information can
easily acquired by the intruders.
In the literature, there are several papers that address
multi-modal ear and face recognition. Superresolution based
multi-modal recognition has been proposed for face and iris
image fusion, and is shown to further improve recognition per
formance by capitalising on direct super-resolving the features
which are used for recognition [2] . Wang et. al [3] adopt an effi
cient feature-level fusion scheme for iris and face in series, and
normalizes the original features of iris and face using z-score
model to eliminate the unbalance in the order of magnitude and
the distribution between two different kinds of feature vectors,
and then connect the normalized feature vectors in serial rule,
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Proceedings of the 2013 International Conference on Wavelet Analysis and Pattern Recognition, Tianjin, 14-17 July, 2013
which has proved to be effective. Lian et. al [4] proposes face
iris multimodal biometric system based on fusion at matching
score level using support vector machine (SVM). The perfor
mances of face and iris recognition can be enhanced using a
proposed feature selection method to select an optimal subset
of features. The results show that the proposed feature selection
method is able improve the classification accuracy in terms of
total error rate. The design of a multi-biometric system is de
pendent on the application. They differ from one another in
terms of their architecture, the number and the choice of the
biometric modalities and the methods used for the integration
tion, Hough transform and normalize the iris image by
the Daugman's Rubber Sheet Model, and extract the
iris feature with the Contourlet Transform.
Step 3 Apply the illumination normalization Walsh Hadamard
transform as the facial preprocessing, and then extrac
t (2D)2PCA vector of the training image as the facial
feature.
Step 4 Form a new feature vector based on the iris and facial
feature extracted above by the fusion strategy.
Step 5 Construct the High Dimensional Covering Space by
the new feature vectors trained by biomimetic pattern
or fusion of information. recognition algorithm.
In this paper, a multi-modal face and ear biometric system Step 6 Achieved the final recognition result by the judgment
is presented, the proposed biometric technique tends to make
full use of the Contourlet Transform [5] and (2D)2PCA [6-7]
to extract the features of iris and face images, and then a new
feature vector was form by the simply weighted concatenated
way. The novel fusion feature is sent to the high dimension
al covering space which is trained by the biomimetic pattern
recognition algorithm, to decide which class this sample be
longs with the rejected mode, rather than the traditional clas
sifier (such as K-nearest neighbor, SVM, etc. with only the
classification mode.
2. The Proposed Multimodal Biometric Recognition
Algorithm
of whether the probe image is in or out of the High
Dimensional Covering Space.
The Complex Geometry Covering in High
Dimensional Space
Figure 1. Framework of multi modal biometric
recognition process with iris and facial images
The multimodal biometric recognition framework presented in 2.1. Preprocess and Feature Extraction of Iris Images this paper is illustrated in Fig. 1, in which the Canny Edge De-
tection, Hough Transform and the Daugman's Rubber Sheet Iris recognition has been considered as an effective way for us
Model is utilized in the iris preprocess, while in the illumination er authentication. One important characteristic of the iris is
normalization Walsh-Hadamard transform is adopted in the fa- that, it is so unique that no two irises are alike, even among i
cial preprocess. Detail steps of multimodal biometric recogni- dentical twins, in the entire human popUlation [8] . The visible
tion process is as follows: characteristics of human iris, such as freckles, coronas, stripes
Step 1 Acquire an iris image and a facial image with cameras and et.al, which are generally called the texture of the iris, are
respectively. unique to each subject [9-10] . In this paper, the Canny Edge
Step 2 Preprocess the iris image with the canny edge detec- Detection and Hough Transform is adopted to estimate the iris
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Proceedings of the 2013 International Conference on Wavelet Analysis and Pattern Recognition, Tianjin, 14-17 July, 2013
(g)
Figure 2. Preprocessing of the iris image, (a) In
put iris image; (b) Edge detected image; (c) lo
cate pupil and iris boundary; (d) Detected top
and bottom eyelid region; (e) Segmented iris im
age; (f) Normalized iris image
boundary, then the Daugman's Rubber Sheet Model is used to
normalize the iris image, and finally the Contourlet Transform
is employed to extract the iris feature. Details involve in prepro-
ber Sheet Model to achieve this goal.
In feature extraction process of the iris image, here we use the
Contourlet Transform, developed by Do and Vetterli [5] . It is a
new two-dimensional extension of the wavelet transform using
multi-scale and direction- al filter banks that can deal effective
ly with images having smooth contours. The Contourlet expan
sion is composed of basis images oriented at various directions
in multiple scales, with flexible aspect ratios. Given this rich set
of basis images, the contourlet transform effectively captures s
mooth contours that are the dominant feature in natural images.
The main difference between contourlets and other multi-scale
directional systems is that the contourlet transform allows for
different and flexible number of directions at each scale, while
achieving nearly critical sampling. Fig. 3 shows a multiscale
and directional decomposition using a combination of a Lapla
cian pyramid (LP) and a directional filter bank (DFB) . Band
pass images from the LP are fed into a DFB so that directional
cess and feature extraction of the iris image are given as below.
Preprocess of the iris image, as shown in Fig. 2, including the
following steps: information can be captured. The scheme can be iterated on Step 1 Edge Map Generation: due to the significant feature the coarse image. Specifically, let Specifically, let ao[n] be the
of handling spurious noisy images of canny operator, input image. The output after the LP stage is J bandpass images canny edge detection algorithm is used to generate the bj [n] ; j = 1,2, . . . ,J (in the fine-to-coarse order) and a lowpass edge map of the iris image here. image aj [n] . That means, the j-th level of the LP decomposes
Step 2 Circular Boundaries and Parameters Estimation: the the image aj-l [n] into a coarser image aj [n] and a detail image edge map above is used to locate the exact boundary bj[n] . Each bandpass image bj[n] is further decomposed by an of pupil and iris by Hough transform for its ability of ij-Ievel DFB into 21jbandpass directional images c1j j,k [n] ; k =
identifying positions of circular shapes, the parameters 0,1, . . . ,21j -1. of the radius and centre coordinates of the circle best
defined by the edge points can be achieved by the a 2.2. Preprocess and Feature Extraction of Facial Images maximum point in the Hough space.
Step 3 Eyelids and Eyelashes Isolation: the eyelids and eye- The illumination normalization of the facial image is crucial
lashes may corrupt the iris pattern, removal of such important in practical face recognition system, because it is
noises is essential for reliable iris information. Here, one of the key factors influences the recognition performance.
eyelids are isolated by fitting a line to the upper and Here, we adopted the block-wise two-dimensional Walsh
lower eyelid using the linear Hough transform, and a Hadamard transform (2D-WHT) to handle the illumination
threshold is used to isolate eyelashes. variation problem. Then a two-directional two-dimensional
Step 4 Iris image Normalization: normalization of the iris im- PCA, also named (2D)2PCA, proposed in [6] by Zhang and
age involves unwrapping the iris and converting it into Zhou, is used to extract the facial feature after the illumina
its polar equivalent. Here we use the Daugman's Rub- tion normalization process. (2D)2PCA, which considered si-
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Proceedings of the 2013 International Conference on Wavelet Analysis and Pattern Recognition, Tianjin, 14-17 July, 2013
image
bandpass directional subbands
_,-----·IJ bandpass directional subbands
2.3. Fusion feature vector construction via combination
of the iris and facial vector
After extracting the iris and face feature via 2DPCA and Con
tourlet transform respectively, we can get a d dimensional fea
ture F face and x dimensional feature Firisrespectively, where
Fface={Fpl, Fp2, ... , Fpd}, Firis={FLl' FL2, ... , FLx}, then
the max-min regularization principle is adopted to normalize "' the feature vector, thus the following equation can be acquired
Figure 3. The contourlet filter bank: first, a mul
tiscale decomposition by the Laplacian pyramid
is computed, and then a directional filter bank is
applied to each bandpass channel.
multaneously the row and column directions was a generaliza
tion two-dimensional principal component analysis (2DPCA)
method [7], and reported to be efficient while the number of
coefficients is smaller than the previous method. The whole
process of illumination normalization and feature extraction
of facial images on combination of block-wise 2D-WHT and
(2D)2PCA, including the following steps:
Step 1 For a given facial image A', transform it into the loga-
I Fface - min(Fface) Fface = (F ) . (F ) max face - mln face
I Firis - min( Firis) Firis = (F ) . (F ) max iris - mln iris
(1)
(2)
Finally, the new fusion vector can be acquired via the weighted
concatenated way by the following equation
(3)
where Wl and W2 is the weight value of face and iris feature
while maintaining Wl +W2=1. The fusion feature F in equation
(3) will be the final multi-modal feature adopted in the follow
ing recognition process. For the high dimensionality brought
by feature fusion, we just simply use principal component anal
ysis (PCA) method to extract the statistically indenpendent fea
tures here.
rithm domain and divide it into 8x 8 blocks, apply the 2.4. Multi-modal Biometric Recognition via Biomimet-
WHT to each block. Zero k dimension low-frequency
WHT coefficients as the zigzag mode. ic Pattern Recognition
Step 2 Apply the inverse WHT to each block, the illumination Biomimetic Pattern Recognition (BPR) [11] was first proposed image A' can be achieved.
Step 3 Apply 2DPCA and Alternative 2DPCA to facial image,
we obtain projection matrices X and Z.
Step 4 Project the mby nimage A' onto X and Z simulta
neously, yielding a q by d matrix X and C where
C = ZT A' X, it is called the coefficient matrix in im
age representation and the feature matrix in face recog
nition. According to above steps, we can obtain the
facial feature vector by column remap the matrix C.
as a new pattern recognition model by academician Wang
Shoujue in 2002. Different from the "division" concept of tra
ditional pattern recognition, BPR emphasizes the view point of
the function and mathematical model of pattern recognition on
the concept of "cognition", which is much closer to the function
of human being.
In this paper, an n-dimensional hyper-sausages neuron is
applied in the implementation of BPR. According to the theo
ry of high dimensional hyper-surfaces, a neuron can construct
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Proceedings of the 2013 International Conference on Wavelet Analysis and Pattern Recognition, Tianjin, 14-17 July, 2013
various types of complex closed hyper-surface. For easier im- respectively in the following experiments to evaluate the per
plementing the BPR, an n-dimensional hyper-sausages neuron formance of the proposed modal and algorithm. CASIA iris
is introduced here. So the union of hyper-sausages, the topo-
logical product of line segments and hyper-surface, can be a
suitable basic shape (sets Pi) to cover the region of samples
of the same class in the feature space approximately (set P' a ) .
Specifically, consider the original samples set Y, let Y' be a sub-
set of Y with} elements, as follows
B = {xl x = ¥i' (i = 0, 1,2, ... , n),
database collected by the Institute of Automation, Chinese A
cademy of Sciences [12] contains 756 gray-scale eye images
( 320x 280 pixels) with 108 unique eyes and 7 different im
ages of each eye, these images are mainly from Asians differ
from ages, and taken twice separately in two months, half in a
month. Here 700 images (100 unique eyes, each eye has 7 im
ages) were selected randomly to perform our experiments. For
the face images, we used a subset of AR face database here,
(4) since it is substantially more challenging. AR database [13]
where y' c Y, d is selected constant. Let} neurons cover P a
approximately, and then the covering of i-th neuron Pj is
consists of over 4,000 frontal images for 126 individuals. For
each individual, 26 pictures were taken in two separate session
s. These images include more facial variations, including illu
Pi = {xl = p(x,y) ::; k,y E Bi,x ERn}
Bi = { xl x = o:Y' + (1 - o:)¥i�l' 0: E (0,1) } The covering of all} neurons is: P� = ui�� Pi. The function of Hyper-Sausages Neuron (HSN) is
Where
d2(x,�) fHSN(X) = sgn(2 r6 - 0.5)
Ilx - xlI12,q(x, Xl, X2) < 0
Ilx - x2112,q(x, Xl, X2) > Ilx - x211 Ilx - xll12 - q2(X, Xl, x2),otherwise
q(X, Xl, X2) = \ X - Xl, II�: = ��II )
(5) mination change, expressions, and facial disguises comparing
to other existing databases. A subset of the data set consist(6)
ing of 50 male subjects and 50 female subjects (each person
has 7 images without occlusion) are chosen for the experiment.
Fig. 4 shows some examples of face and iris images in the ex
periments. All experiments in the iris feature extraction process
(7) using the contourlet transform, in the LP stage we use the "9-7"
filters. We choose "9-7" biorthogonal filters because they have
been shown to provide the best results for images, partly be-
(8)
cause they are linear phase and are close to being orthogonal.
In the DFB stage we use the "pkva" filters. We then choose
the Low frequency coefficients after 3 level Laplacian pyramid
(LP) decomposition as features of the iris image, and remap it
(9) into a vector. For the face feature extraction process, 90% of
Where x is feature vector of a testing sample. While Xl and X2 are feature vectors of two training samples which determine a
line segment. ( - ) in equation (9) represents the inner product
operation. II . II denotes 12 norm.
3. Experimental results
In this paper, we used the face and iris images from t
wo public standard AR face database and CASIA iris database
206
Figure 4. Some examples of face and iris images
from AR face database and CASIA iris database.
Proceedings of the 2013 International Conference on Wavelet Analysis and Pattern Recognition, Tianjin, 14-17 July, 2013
the energy of (2D)2PCA is adopted. All the experiments are all varying conditions of TTR*. By fusing iris and face biomet
implemented for 100 times, the recognition rate here takes the ric, the performance of the system can increase to 100% when
average results. the TTR * equals to 512 or 6/1. Though the single iris recogni-
Table 1. Results of average true recognition rate
(%) by the proposed single and multi-modal
based biometric recognition algorithm under d
ifferent training and testing sample ratio (TTR*)
without dimension reduction via 100 times inde
pendent experiments.
Recognition Modal TIR * 611 5/2 4/3 3/4 215 116
Face modal 98.69% 98.12% 96.75% 95.49% 93.28% 89.62%
Iris modal
Joint face and iris modal
100%
100%
100% 98.89% 97.63% 95.32% 93.25%
100% 99.54% 98.67% 98.73% 97.57%
Table 2. True recognition rate (%) comparison of
proposed algorithm and other algorithms under
different feature dimension via peA dimension
reduction with a training and testing sample ra
tio equal to TTR*=4/3.
Algorithm Dimension 64 128 256 512
peA plus BP - iris only 90.51% 93.37% 94.26% 94.88%
peA plus REF - iris only 90.69% 94.91% 95.01% 95.77%
PCA plus BP - face only 86.98% 90.71% 90.24% 92.66%
peA plus REF - face only 89.56% 92.45% 92.89% 93.09%
peA plus BP -Joint face and iris 94.94% 95.09% 96.58% 97.64%
peA plus REF -Joint face and iris 96.17% 97.73% 98.26% 98.85%
Proposed -Joint face and iris 98.81% 98.68% 99.15% 99.32%
We tested the performance of our approach for both sin-
tion modal can achieve 100% true recognition rate in the same
condition, the proposed multi-modal recognition modal outper
forms the iris one in a low TTR *. Thus it can overcome the con
dition of deficiency of training samples and maintain a robust
result in all conditions.
To further justify the performance of the multi-model bio
metric recognition system in this work, we compare its perfor
mance to the well known Back propagation (BP) and radius
basis function (RBF) neural network method. The results are
presented in Table 2. It indicated that the multimodal feature
fusion will benefit the recognition result. The proposed multi
model biometric recognition method outperforms than the sin
gle face or iris recognition model based biometric recognition
method, which yielded a true recognition of above 99% when
the dimension higher than 256 dimension. For the lower di
mensional feature, the joint face and iris modal also performs
better than the single one, though the recognition rate decrease
a little bit.
4. Conclusions
In this paper, a novel joint face and iris based biometric
recognition approach based on the Contourlet transform and
biomimetic pattern recognition was proposed. The iris and
face feature are extracted based on the Contourlet transform
and (2D)2PCA respectively, and then fused in a weighted con
catenated way to achieve robust performance to single biomet
ric variations. Finally, the high dimensional space covering
gle and multi-modal biometric recognition separately and then method based on biomimetic pattern recognition was adopted
compared their performances in terms of varying training and here to finish the recognition task. Experiments results show
testing sample ratio (TTR*). The results of our experiments that, the proposed multi-modal biometric recognition method
are reported in Table 1. It indicated that the joint iris and face can achieve relatively high performance, thus it could be wide
modal outperforms the single face modal and iris modal under ly used in personal authentication applications in the future.
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Proceedings of the 2013 International Conference on Wavelet Analysis and Pattern Recognition, Tianjin, 14-17 July, 2013
Acknowledgement
This work is supported by National Natural Sci
ence Foundation Under Grand No.61072127; and Natural
Science Foundation of Guangdong Province, P.R.e. Un
der Grand NO.10152902001000 002, No.S2011040004211,
NO.S2011010001085 and No. 10151064101000000; and Foun
dation for Distinguished Young Talents in Higher Education
of Guangdong, China Under Grand NO.2012LYM _0127; and
Special fund of Zhujiang science and technology new star of
Guangzhou city NO.2011122 00084; and Science and technol
ogy plan project of Guangdong, No. 201IB080701045.
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