Report face recognition : ArganRecogn

UNIVERSITY OF CAGLIARI
FACULTY OF SCIENCE
Major Project Proposal
Face Recognition Using a Deep Convolutional
Neural Network and a Graph-Based
Distributed Computation Framework:
”ArganRecogn”
Submitted by:
CHAOUA Ilyas
IGUIDER Walid
Submitted to:
Mr. Silvio Barra
Department of Computer Science
University of Cagliari
February 14, 2017

Abstract
The goal of this report is the presentation of our biometry and secu-
rity course’s project: Face recognition for Labeled Faces in the Wild dataset
using Convolutional Neural Network technology with Graphlab Framework.
Deep learning is the new big trend in machine learning. It had many recent
successes in computer vision, automatic speech recognition and natural lan-
guage processing. We will go through general ideas and structures of face
recognition using deep learning, important issues to load, summarize and
visualize the dataset, we will explain the critical techniques and algorithms,
and ﬁnally give some predictions and present our results.
i

Contents
Abstract i
Table of contents ii
List of Figures iii
1 Introduction 1
2 Data Collection 3
3 Face Detection 4
4 Splitting the Data 5
5 Network architecture and training 6
5.1 Convolutional Neural Network . . . . . . . . . . . . . . . . . . 6
5.2 Convolutional Neural Networks Architecture . . . . . . . . . . 6
5.2.1 Convolution Layer . . . . . . . . . . . . . . . . . . . . 7
5.2.2 Pooling Layer . . . . . . . . . . . . . . . . . . . . . . . 7
5.2.3 Training the CNN . . . . . . . . . . . . . . . . . . . . . 7
6 Test Set 9
7 Conclusion 10
Certiﬁcate of approval 11
Copyright 12
References 13
ii

List of Figures
1 The process of the project. . . . . . . . . . . . . . . . . . . . . 2
2 Image of the identity : Johnny Deep . . . . . . . . . . . . . . 4
3 Face of the identity : Johnny Deep. . . . . . . . . . . . . . . . 4
4 Beginning Test set . . . . . . . . . . . . . . . . . . . . . . . . 5
5 ArganRecogn Test set . . . . . . . . . . . . . . . . . . . . . . 5
6 Beginning Training set . . . . . . . . . . . . . . . . . . . . . . 5
7 ArganRecogn Training set . . . . . . . . . . . . . . . . . . . . 5
iii

1 Introduction
Face Recognition went mainstream in the early 1960’s when Helen
Chan and Charles Bisson, worked on using the computer to recognize hu-
man faces (Bledsoe 1966a, 1966b; Bledsoe and Chan 1965). The ﬁrst semi-
automated system for face recognition required the administrator to locate
features (such as eyes, ears, nose, and mouth) on the photographs before
it calculated distances and ratios to a common reference point, which were
then compared to reference data. In the 1970’s, Goldstein, Harmon, and
Lesk used 21 speciﬁc subjective markers such as hair color and lip thickness
to automate the recognition. The problem with both of these early solu-
tions was that the measurements and locations were manually computed. In
1988, Kirby and Sirovich applied principle component analysis, a standard
linear algebra technique, to the face recognition problem. In 1991, Turk and
Pentland discovered that while using the eigenfaces techniques, the residual
error could be used to detect faces in images a discovery that enabled reliable
real-time automated face recognition systems.
Recent progress in this area has been due to two factors:
1. End to End learning for the task using a convolutional neural network.
2. The availability of very large scale training datasets.
In this report, we focus on image-based face recognition. Given a image from
LFW dataset, we’d like to detect faces of any person inside and know who
he/she is. Towards this goal, we generally followed this procedure :
1

Figure 1: The process of the project.
2

2 Data Collection
In the world of face recognition, the dataset plays the role of raw ma-
terial, for this reason, we choose to work with Labeled Faces in the Wild
: LFW, a database of face photographs designed for studying the problem
of unconstrained face recognition. The data set contains more than 13,000
images of faces collected from the web. Each face has been labeled with the
name of the person pictured. 1680 of the people pictured have two or more
distinct photos in the data set.
Dataset Identities Images
LFW 5749 13233
Beginning Set 5751 13229
Ours:ArganRecogn 5751 25651
We proposed a procedure to create a reasonably large face dataset :
ArganRecogn with the characteristic that each identity has more than three
images whilst the Beginning Set contains 4072 identities with only one image
(1679 identities have more than one image). To this end we downloaded
more than 13987 new images from Google Images. The method for collecting
images is writing with python using open source scripts available on the web.
We employ this procedure to build a dataset with over 25651 images.
3

3 Face Detection
In this section we propose an open source method to efficiently detect
and extract faces from an image given using OpenCV, the most popular li-
brary for computer vision. Originally written in C/C++, it now provides
bindings for Python.
For face detection, the algorithm starts at the top left of a picture and moves
down across small blocks of data, looking at each block, constantly asking,
“Is this a face? . . . Is this a face? . . . Is this a face?” Since there are
6,000 or more tests per block, you might have millions of calculations to do,
which will grind your computer to a halt. To get around this, OpenCV uses
cascades.
Like a series of waterfalls, the OpenCV cascade breaks the problem of de-
tecting faces into multiple stages. For each block, it does a very rough and
quick test. If that passes, it does a slightly more detailed test, and so on.
The algorithm may have 30-50 of these stages or cascades, and it will only
detect a face if all stages pass. The advantage is that the majority of the
pictures will return negative during the first few stages, which means the
algorithm won’t waste time testing all 6,000 features on it. Instead of taking
hours, face detection can now be done in real time.
Though the theory may sound complicated, in practice it is quite easy. The
cascades themselves are just a bunch of XML files that contain OpenCV data
used to detect objects. You initialize your code with the cascade you want,
and then it does the work for you.
Figure 2: Image of the
identity : Johnny Deep
Figure 3: Face of the
identity : Johnny Deep.
4

4 Splitting the Data
After applying our face detection algorithm based on OpenCV library,
we loaded all the resulting data and started the data splitting. First we split
the data into the following :
• Test data, which contains the images of all the identities such that we
have one image by identity (5751 image).
• The other data contains at least one image by identity(19900 image).
Then we took 80% of the other data for the training the network and 20%
for the validation.
The following ﬁgures represents information about the experimental test sets.
Figure 4: Beginning Test set Figure 5: ArganRecogn Test set
The following ﬁgures represents information about the experimental train-
ing sets.
Figure 6: Beginning Training set Figure 7: ArganRecogn Training set
5

5 Network architecture and training
5.1 Convolutional Neural Network
In this section, we explain the algorithms and tools for building and
training the convolutional neural network using GraphLab, a Python library,
backed by a C++ engine, for quickly building large-scale, high-performance
data products. GraphLab provides machine learning algorithms including
deep learning, boosted trees, and factorization machines and can be run the
code on your laptop or in a distributed system, using a Hadoop Yarn or EC2
cluster.
Convolutional neural networks are a special type of feed-forward networks.
These models are designed to emulate the behaviour of a visual cortex. CNNs
perform very well on visual recognition tasks. CNNs have special layers called
convolutional layers and pooling layers that allow the network to encode cer-
tain images properties.
5.2 Convolutional Neural Networks Architecture
The simplest architecture of a convolutional neural networks starts
with an input layer (images) followed by a sequence of convolutional layers
and pooling layers, and ends with fully-connected layers. The convolutional
layers are usually followed by one layer of ReLU activation functions.
The convolutional, pooling and ReLU layers act as learnable features extrac-
tors, while the fully connected layers acts as a machine learning classiﬁer.
Furthermore, the early layers of the network encode generic patterns of the
images, while later layers encode the details patterns of the images.Note that
only the convolutional layers and fully-connected layers have weights. These
weights are learned in the training phase.[7]
6

5.2.1 Convolution Layer
This layer consists of a set of learnable filters that we slide over the image
spatially, computing dot products between the entries of the filter and the
input image. The filters should extend to the full depth of the input image.
For example, if we want to apply a filter of size 5x5 to a colored image of
size 32x32, then the filter should have depth 3 (5x5x3) to cover all 3 color
channels (Red, Green, Blue) of the image. These filters will activate when
they see same specific structure in the images.[7]
5.2.2 Pooling Layer
Pooling is a form of non-linear down-sampling. The goal of the pooling layer
is to progressively reduce the spatial size of the representation to reduce the
amount of parameters and computation in the network, and hence to also
control overfitting. There are several functions to implement pooling among
which max pooling is the most common one. Pooling is often applied with
filters of size 2x2 applied with a stride of 2 at every depth slice. A pooling
layer of size 2x2 with stride of 2 shrinks the input image to a 1/4 of its
original size.[7]
5.2.3 Training the CNN
The general workflow of training a neural network using GraphLab involves
three steps:
1. Create a convolutional neural network : CNN.
7

2. Tweak the CNN parameters (number of iterations, target class, met-
rics...) so that they are appropriate for the desired task.
3. Load the classifier and give it the CNN as a parameter to begin the
training using the given network architecture and parameters.
During the data splitting, we dedicated 78% of the whole dataset for the
training and validation. Thus we did a random split of the resulting dataset
such that 80% of the data is aimed to be the training set whereas the re-
maining 20% is for the validation. As a first experience of network training
we tried to give the classifier 300 iteration, which gave us, after the valida-
tion of the training, an accuracy of about 65%. Then we started increasing
the number of iterations until we reached a maximum accuracy at the 600th
iteration which was about 87%.
In a first time we trained the network CNN using the Beginning training
set with a learning rate of 0.001, a momentum of 0.9 and the metric: ”ac-
curacy,recall@2” for 600 iterations. After that we experimented an other
training for the CNN with the same parameters using ArganRecogn training
set. In the next section, we will present our results for the both attempts.
8

6 Test Set
Now that we have a trained model, we can use it to make predictions.
To do this, we can use the ArganRecogn test set (previously described) which
consists of 5751 faces and present 22% of global data. This set contains faces
that have never been subjected to the network.
In the following we ﬁrst test several variations of the proposed models and
training data using the beginning test set based on LFW database and Argag-
nRecogn test set to compare the performance. Brieﬂy, these are the results
I have achieved using MacBook 12”-Intel HD Graphics 5300 1536MB for
beginning test set after 600 iterations:
Training time (sec) : 23697.8544
Training accuracy Validation accuracy Training recall@2 Validation recall@2
0.8764 0.1527 0.9405 0.1799
Test results for beginning test set
These are the results I have achieved using MacBook 12”-Intel HD Graph-
ics 5300 1536MB for ArganRecogn test set after 600 iterations:
Training time (sec) : 63363.5553
Training accuracy Validation accuracy Training recall@2 Validation recall@2
0.7312 0.0865 0.8342 0.1023
Test results for ArganRecogn test set
9

7 Conclusion
In this work we have used a large scale dataset, with small label noise,
while keeping down the number of manual annotation. The main idea was to
train a classiﬁer to rank the data presented to the annotators. This procedure
has been developed for faces, but is evidently suitable for other object classes
as well as ﬁne grained tasks. Then as another contribution we have showed
that a well trained deep convolutional neural network can achieve very good
results comparing to the state of the art.
10

Certificate of approval
We found the students Ilyas Chaoua and Walid Iguider to be hardworking,
skilled, bonafide and ready to undertake any commercial and industrial work
related to their field of study.
Professor. Silvio Barra
(Project Supervisor)
.............................
11

Copyright
MIT License
Copyright (c) [2017] [ArganRecogn]
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation ﬁles (the ”Software”), to deal
in the Software without restriction, including without limitation the rights to
use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
of the Software, and to permit persons to whom the Software is furnished to
do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED ”AS IS”, WITHOUT WARRANTY OF
ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR
ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE
OR OTHER DEALINGS IN THE SOFTWARE.
Department of Computer Science
University of Cagliari
Cagliari, Italy
12

References
[1] http://cs231n.github.io/convolutional-networks/
karpathy@cs.stanford.edu.
[2] https://turi.com/products/create/docs/graphlab.toolkits.deeplearning.html?highlight=deep
[3] https://www.robots.ox.ac.uk/vgg/publications/2015/parkhi15/parkhi15.pdf.
[4] Yoshua Bengio. Practical recommendations for gradient-based training of
deep architectures,neural networks: Tricks of the trade. Springer Berlin
Heidelberg, 437-478, 2012.
[5] Gary B. Huang, Manu Ramesh, Tamara Berg, and Erik Learned-Miller.
Labeled faces in the wild: A database for studying face recognition in
unconstrained environments. Technical Report 07-49, University of Mas-
sachusetts, Amherst, October 2007.
[6] Yann LeCun. Gradient-based learning applied to document recognition.
Proceedings of the IEEE 86.11, 2278-2324, 1998.
[7] Adil Moujahid. http://adilmoujahid.com/posts/2016/06/introduction-
deep-learning-python-caﬀe/. 2016.
13

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