Julian Fierrez

Prof. Julian Fierrez

Universidad Autonoma de Madrid
orcid

Research Focus & Metrics

Academic Career Length

23Years (2004-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 December 2007 in Pattern Recognition Letters
Verified
Journal Article
Closed access
Julian FierrezJulian Fierrez
Julian Fierrez
JOJavier Ortega-Garcia
Javier Ortega-Garcia
DRDaniel Ramos
Daniel Ramos
JGJoaquin Gonzalez-Rodriguez
Joaquin Gonzalez-Rodriguez

1 June 2021 in IEEE Transactions on Pattern Analysis and Machine Intelligence
Verified
Journal Article
Closed access
AMAythami Morales
Aythami Morales
Julian FierrezJulian Fierrez
Julian Fierrez
RVRuben Vera-Rodriguez
Ruben Vera-Rodriguez
RTRuben Tolosana
Ruben Tolosana
This work proposes a novel privacy-preserving neural network feature representation to suppress the sensitive information of a learned space while maintaining the utility of the data. The new international regulation for personal data protection forces data controllers to guarantee privacy and avoid discriminative hazards while managing sensitive data of users. In our approach, privacy and discrimination are related to each other. Instead of existing approaches aimed directly at fairness improvement, the proposed feature representation enforces the privacy of selected attributes. This way fairness is not the objective, but the result of a privacy-preserving learning method. This approach guarantees that sensitive information cannot be exploited by any agent who process the output of the model, ensuring both privacy and equality of opportunity. Our method is based on an adversarial regularizer that introduces a sensitive information removal function in the learning objective. The method is evaluated on three different primary tasks (identity, attractiveness, and smiling) and three publicly available benchmarks. In addition, we present a new face annotation dataset with balanced distribution between genders and ethnic origins. The experiments demonstrate that it is possible to improve the privacy and equality of opportunity while retaining competitive performance independently of the task.

6 July 2020 in IEEE Journal of Selected Topics in Signal Processing
Verified
Journal Article
Closed access
João C. NevesJoão C. Neves
João C. Neves
RTRuben Tolosana
Ruben Tolosana
RVRuben Vera-Rodriguez
Ruben Vera-Rodriguez
Vasco LopesVasco Lopes
Vasco Lopes
Hugo ProençaHugo Proença
Hugo Proença
Julian FierrezJulian Fierrez
Julian Fierrez
The availability of large-scale facial databases, together with the remarkable progresses of deep learning technologies, in particular Generative Adversarial Networks (GANs), have led to the generation of extremely realistic fake facial content, raising obvious concerns about the potential for misuse. Such concerns have fostered the research on manipulation detection methods that, contrary to humans, have already achieved astonishing results in various scenarios. In this study, we focus on the synthesis of entire facial images, which is a specific type of facial manipulation. The main contributions of this study are four-fold: i) a novel strategy to remove GAN fingerprints from synthetic fake images based on autoencoders is described, in order to spoof facial manipulation detection systems while keeping the visual quality of the resulting images; ii) an in-depth analysis of the recent literature in facial manipulation detection; iii) a complete experimental assessment of this type of facial manipulation, considering the state-of-the-art fake detection systems (based on holistic deep networks, steganalysis, and local artifacts), remarking how challenging is this task in unconstrained scenarios; and finally iv) we announce a novel public database, named iFakeFaceDB, yielding from the application of our proposed GAN-fingerprint Removal approach (GANprintR) to already very realistic synthetic fake images. The results obtained in our empirical evaluation show that additional efforts are required to develop robust facial manipulation detection systems against unseen conditions and spoof techniques, such as the one proposed in this study.

10 September 2021 in IEEE Transactions on Technology and Society
Verified
Journal Article
Open access
PTPhilipp Terhorst
Philipp Terhorst
JKJan Niklas Kolf
Jan Niklas Kolf
MHMarco Huber
Marco Huber
FKFlorian Kirchbuchner
Florian Kirchbuchner
NDNaser Damer
Naser Damer
Arjan KuijperArjan Kuijper
Arjan Kuijper
Face recognition (FR) systems have a growing effect on critical decision-making processes. Recent works have shown that FR solutions show strong performance differences based on the user’s demographics. However, to enable a trustworthy FR technology, it is essential to know the influence of an extended range of facial attributes on FR beyond demographics. Therefore, in this work, we analyze FR bias over a wide range of attributes. We investigate the influence of 47 attributes on the verification performance of two popular FR models. The experiments were performed on the publicly available MAAD-Face attribute database with over 120M high-quality attribute annotations. To prevent misleading statements about biased performances, we introduced control group-based validity values to decide if unbalanced test data causes the performance differences. The results demonstrate that also many nondemographic attributes strongly affect recognition performance, such as accessories, hairstyles and colors, face shapes, or facial anomalies. The observations of this work show the strong need for further advances in making the FR system more robust, explainable, and fair. Moreover, our findings might help to a better understanding of how FR networks work, enhance the robustness of these networks, and develop more generalized bias-mitigating FR solutions.

1 January 2012 in Future Generation Computer Systems
Verified
Journal Article
Open access
Javier GalballyJavier Galbally
Javier Galbally
FAFernando Alonso-Fernandez
Fernando Alonso-Fernandez
Julian FierrezJulian Fierrez
Julian Fierrez
JOJavier Ortega-Garcia
Javier Ortega-Garcia
A new software-based liveness detection approach using a novel fingerprint parameterization based on quality related features is proposed. The system is tested on a highly challenging database comprising over 10,500 real and fake images acquired with five sensors of different technologies and covering a wide range of direct attack scenarios in terms of materials and procedures followed to generate the gummy fingers. The proposed solution proves to be robust to the multi-scenario dataset, and presents an overall rate of 90% correctly classified samples. Furthermore, the liveness detection method presented has the added advantage over previously studied techniques of needing just one image from a finger to decide whether it is real or fake. This last characteristic provides the method with very valuable features as it makes it less intrusive, more user friendly, faster and reduces its implementation costs. © 2010 Elsevier B.V. All rights reserved

25 February 2009 in Pattern Analysis and Applications
Verified
Journal Article
Closed access
PDF file
Julian FierrezJulian Fierrez
Julian Fierrez
Javier GalballyJavier Galbally
Javier Galbally
JOJ. Ortega-Garcia
J. Ortega-Garcia
MFM. R. Freire
M. R. Freire
FAFernando Alonso-Fernandez
Fernando Alonso-Fernandez
JGJ. J. Gracia-Roche
J. J. Gracia-Roche