Federico Alvarez

Dr. Federico Alvarez

Grupo de Aplicación de Telecomunicaciones Visuales, Universidad Politécnica de Madrid, Madrid, Spain
orcid

Research Focus & Metrics

Academic Career Length

19Years (2008-Present)

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

Representative Publications

View All Publications
1 September 2019
Verified
Conference Paper
Open access
NZNikolaos Zioulis
Nikolaos Zioulis
AKAntonis Karakottas
Antonis Karakottas
DZDimitrios Zarpalas
Dimitrios Zarpalas
FAFederico Alvarez
Federico Alvarez
PDPetros Daras
Petros Daras
Learning based approaches for depth perception are limited by the availability of clean training data. This has led to the utilization of view synthesis as an indirect objective for learning depth estimation using efficient data acquisition procedures. Nonetheless, most research focuses on pinhole based monocular vision, with scarce works presenting results for omnidirectional input. In this work, we explore spherical view synthesis for learning monocular 360 depth in a self-supervised manner and demonstrate its feasibility. Under a purely geometrically derived formulation we present results for horizontal and vertical baselines, as well as for the trinocular case. Further, we show how to better exploit the expressiveness of traditional CNNs when applied to the equirectangular domain in an efficient manner. Finally, given the availability of ground truth depth data, our work is uniquely positioned to compare view synthesis against direct supervision in a consistent and fair manner. The results indicate that alternative research directions might be better suited to enable higher quality depth perception. Our data, models and code are publicly available at https://vcl3d.github.io/SphericalViewSynthesis/.

24 March 2021 in IEEE Access
Verified
Journal Article
Open access
DMDavid Martin-Gutierrez
David Martin-Gutierrez
GHGustavo Hernandez-Penaloza
Gustavo Hernandez-Penaloza
Alberto Belmonte HernándezAlberto Belmonte Hernández
Alberto Belmonte Hernández
ALAlicia Lozano-Diez
Alicia Lozano-Diez
FAFederico Alvarez
Federico Alvarez
During the last decades, the volume of multimedia content posted in social networks has grown exponentially and such information is immediately propagated and consumed by a significant number of users. In this scenario, the disruption of fake news providers and bot accounts for spreading propaganda information as well as sensitive content throughout the network has fostered applied research to automatically measure the reliability of social networks accounts via Artificial Intelligence (AI). In this paper, we present a multilingual approach for addressing the bot identification task in Twitter via Deep learning (DL) approaches to support end-users when checking the credibility of a certain Twitter account. To do so, several experiments were conducted using state-of-the-art Multilingual Language Models to generate an encoding of the text-based features of the user account that are later on concatenated with the rest of the metadata to build a potential input vector on top of a Dense Network denoted as Bot-DenseNet. Consequently, this paper assesses the language constraint from previous studies where the encoding of the user account only considered either the metadata information or the metadata information together with some basic semantic text features. Moreover, the Bot-DenseNet produces a low-dimensional representation of the user account which can be used for any application within the Information Retrieval (IR) framework.

13 March 2019 in IEEE Transactions on Broadcasting
Verified
Journal Article
Closed access
FAFederico Alvarez
Federico Alvarez
DBDavid Breitgand
David Breitgand
DGDavid Griffin
David Griffin
PAPasquale Andriani
Pasquale Andriani
SRStamatia Rizou
Stamatia Rizou
DJDavid Jiménez
David Jiménez

15 January 2019 in IEEE Sensors Journal
Verified
Journal Article
Closed access
Alberto Belmonte HernándezAlberto Belmonte Hernández
Alberto Belmonte Hernández
GHGustavo Hernandez-Penaloza
Gustavo Hernandez-Penaloza
DGDavid Martin Gutierrez
David Martin Gutierrez
FAFederico Alvarez
Federico Alvarez

13 April 2018 in IEEE MultiMedia
Verified
Journal Article
Open access
FAFederico Alvarez
Federico Alvarez
MPMirela Popa
Mirela Popa
VSVassilios Solachidis
Vassilios Solachidis
GHGustavo Hernandez-Penaloza
Gustavo Hernandez-Penaloza
ABAlberto Belmonte-Hernandez
Alberto Belmonte-Hernandez
PDPetros Daras
Petros Daras
The analysis of multimodal data collected by innovative imaging sensors, Internet of Things devices, and user interactions can provide smart and automatic distant monitoring of Parkinsons and Alzheimers patients and reveal valuable insights for early detection and/or prevention of events related to their health. This article describes a novel system that involves data capturing and multimodal fusion to extract relevant features, analyze data, and provide useful recommendations. The system gathers signals from diverse sources in health monitoring environments, understands the user behavior and context, and triggers proper actions for improving the patients quality of life. The system offers a multimodal, multi-patient, versatile approach not present in current developments. It also offers comparable or improved results for detection of abnormal behavior in daily motion. The system was implemented and tested during 10 weeks in real environments involving 18 patients.

1 June 2021
Verified
Conference Paper
Closed access
GAGeorgios Albanis
Georgios Albanis
NZNikolaos Zioulis
Nikolaos Zioulis
PDPetros Drakoulis
Petros Drakoulis
VGVasileios Gkitsas
Vasileios Gkitsas
VSVladimiros Sterzentsenko
Vladimiros Sterzentsenko
PDPetros Daras
Petros Daras
Pano3D is a new benchmark for depth estimation from spherical panoramas. It aims to assess performance across all depth estimation traits, the primary direct depth estimation performance targeting precision and accuracy, and also the secondary traits, boundary preservation and smoothness. Moreover, Pano3D moves beyond typical intra-dataset evaluation to inter-dataset performance assessment. By disentangling the capacity to generalize in unseen data into different test splits, Pano3D represents a holistic benchmark for 360 o depth estimation. We use it as a basis for an extended analysis seeking to offer insights into classical choices for depth estimation. This results into a solid baseline for panoramic depth that followup works can built upon to steer future progress.