Sergio Escalera

Dr. Sergio Escalera

Computer Vision Centre, Universitat Autònoma de Barcelona, Bellaterra (Cerdanyola), 08193 Barcelona, Spain
orcid

Research Focus & Metrics

Academic Career Length

21Years (2006-Present)

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

Representative Publications

View All Publications
17 June 2021 in IEEE Transactions on Medical Imaging
Verified
Journal Article
Open access
VCVíctor Manuel Campello
Víctor Manuel Campello
PGPolyxeni Gkontra
Polyxeni Gkontra
CICristian Izquierdo
Cristian Izquierdo
CMCarlos Martin-Isla
Carlos Martin-Isla
ASAlireza Sojoudi
Alireza Sojoudi
KLKarim Lekadir
Karim Lekadir
The emergence of deep learning has considerably advanced the state-of-the-art in cardiac magnetic resonance (CMR) segmentation. Many techniques have been proposed over the last few years, bringing the accuracy of automated segmentation close to human performance. However, these models have been all too often trained and validated using cardiac imaging samples from single clinical centres or homogeneous imaging protocols. This has prevented the development and validation of models that are generalizable across different clinical centres, imaging conditions or scanner vendors. To promote further research and scientific benchmarking in the field of generalizable deep learning for cardiac segmentation, this paper presents the results of the Multi-Centre, Multi-Vendor and Multi-Disease Cardiac Segmentation (M&Ms) Challenge, which was recently organized as part of the MICCAI 2020 Conference. A total of 14 teams submitted different solutions to the problem, combining various baseline models, data augmentation strategies, and domain adaptation techniques. The obtained results indicate the importance of intensity-driven data augmentation, as well as the need for further research to improve generalizability towards unseen scanner vendors or new imaging protocols. Furthermore, we present a new resource of 375 heterogeneous CMR datasets acquired by using four different scanner vendors in six hospitals and three different countries (Spain, Canada and Germany), which we provide as open-access for the community to enable future research in the field.

1 July 2018 in Image and Vision Computing
Verified
Journal Article
Closed access
PRPau Rodríguez
Pau Rodríguez
MBMiguel A. Bautista
Miguel A. Bautista
JGJordi Gonzalez
Jordi Gonzalez
Sergio EscaleraSergio Escalera
Sergio Escalera

16 October 2018 in IEEE Transactions on Affective Computing
Verified
Journal Article
Closed access
FNFatemeh Noroozi
Fatemeh Noroozi
CCCiprian Adrian Corneanu
Ciprian Adrian Corneanu
Dorota KaminskaDorota Kaminska
Dorota Kaminska
TSTomasz Sapinski
Tomasz Sapinski
Sergio EscaleraSergio Escalera
Sergio Escalera
Gholamreza AnbarjafariGholamreza Anbarjafari
Gholamreza Anbarjafari
Automatic emotion recognition has become a trending research topic in the past decade. While works based on facial expressions or speech abound, recognising affect from body gestures remains a less explored topic. We present a new comprehensive survey hoping to boost research in the field. We first introduce emotional body gestures as a component of what is commonly known as "body language" and comment general aspects as gender differences and culture dependence. We then define a complete framework for automatic emotional body gesture recognition. We introduce person detection and comment static and dynamic body pose estimation methods both in RGB and 3D. We then comment the recent literature related to representation learning and emotion recognition from images of emotionally expressive gestures. We also discuss multi-modal approaches that combine speech or face with body gestures for improved emotion recognition. While pre-processing methodologies (e.g. human detection and pose estimation) are nowadays mature technologies fully developed for robust large scale analysis, we show that for emotion recognition the quantity of labelled data is scarce, there is no agreement on clearly defined output spaces and the representations are shallow and largely based on naive geometrical representations.

12 February 2020 in IEEE Transactions on Biometrics, Behavior, and Identity Science
Verified
Journal Article
Closed access
SZShifeng Zhang
Shifeng Zhang
ALAjian Liu
Ajian Liu
JWJun Wan
Jun Wan
YLYanyan Liang
Yanyan Liang
GGGuodong Guo
Guodong Guo
SLStan Z. Li
Stan Z. Li
Face anti-spoofing is essential to prevent face recognition systems from a security breach. Much of the progresses have been made by the availability of face anti-spoofing benchmark datasets in recent years. However, existing face anti-spoofing benchmarks have limited number of subjects (≤170) and modalities (≤2), which hinder the further development of the academic community. To facilitate face anti-spoofing research, we introduce a large-scale multi-modal dataset, namely CASIA-SURF, which is the largest publicly available dataset for face anti-spoofing in terms of both subjects and modalities. Specifically, it consists of 1,000 subjects with 21,000 videos and each sample has 3 modalities (i.e., RGB, Depth and IR). We also provide comprehensive evaluation metrics, diverse evaluation protocols, training/validation/testing subsets and a measurement tool, developing a new benchmark for face anti-spoofing. Moreover, we present a novel multi-modal multi-scale fusion method as a strong baseline, which performs feature re-weighting to select the more informative channel features while suppressing the less useful ones for each modality across different scales. Extensive experiments have been conducted on the proposed dataset to verify its significance and generalization capability. The dataset is available at https://sites.google.com/qq.com/face-anti-spoofing/welcome/challengecvpr2019?authuser=0.

7 November 2008 in IEEE Transactions on Pattern Analysis and Machine Intelligence
Verified
Journal Article
Closed access
Sergio EscaleraSergio Escalera
Sergio Escalera
OPOriol Pujol
Oriol Pujol
PRPetia Radeva
Petia Radeva
A common way to model multiclass classification problems is to design a set of binary classifiers and to combine them. Error-correcting output codes (ECOC) represent a successful framework to deal with these type of problems. Recent works in the ECOC framework showed significant performance improvements by means of new problem-dependent designs based on the ternary ECOC framework. The ternary framework contains a larger set of binary problems because of the use of a ldquodo not carerdquo symbol that allows us to ignore some classes by a given classifier. However, there are no proper studies that analyze the effect of the new symbol at the decoding step. In this paper, we present a taxonomy that embeds all binary and ternary ECOC decoding strategies into four groups. We show that the zero symbol introduces two kinds of biases that require redefinition of the decoding design. A new type of decoding measure is proposed, and two novel decoding strategies are defined. We evaluate the state-of-the-art coding and decoding strategies over a set of UCI machine learning repository data sets and into a real traffic sign categorization problem. The experimental results show that, following the new decoding strategies, the performance of the ECOC design is significantly improved.

1 June 2016
Verified
Conference Paper
Closed access
JWJun Wan
Jun Wan
SLStan Z. Li
Stan Z. Li
YZYibing Zhao
Yibing Zhao
SZShuai Zhou
Shuai Zhou
IGIsabelle Guyon
Isabelle Guyon
Sergio EscaleraSergio Escalera
Sergio Escalera
In this paper, we present two large video multi-modal datasets for RGB and RGB-D gesture recognition: the ChaLearn LAP RGB-D Isolated Gesture Dataset (IsoGD) and the Continuous Gesture Dataset (ConGD). Both datasets are derived from the ChaLearn Gesture Dataset (CGD) that has a total of more than 50000 gestures for the "one-shot-learning" competition. To increase the potential of the old dataset, we designed new well curated datasets composed of 249 gesture labels, and including 47933 gestures manually labeled the begin and end frames in sequences. Using these datasets we will open two competitions on the CodaLab platform so that researchers can test and compare their methods for "user independent" gesture recognition. The first challenge is designed for gesture spotting and recognition in continuous sequences of gestures while the second one is designed for gesture classification from segmented data. The baseline method based on the bag of visual words model is also presented.