Publications

2026

• D. Freire-Obregón, J. Sálas-Cáceres, M. Castrillón-Santana, “Dynamic Dropout: Leveraging Conway’s Game of Life for Neural Networks Regularization”, IEEE International Conference on Computing and Machine Intelligence (ICMI), 2026. Arxiv
• D. Freire-Obregón, “Emotional Modulation in Swarm Decision Dynamics”, International Conference on Agents and Artificial Intelligence (ICAART), 2026. Arxiv
• D. Freire-Obregón, O. J. Santana, J. Lorenzo-Navarro, D. Hernández-Sosa, M. Castrillón-Santana, “Multi-year long-term person re-identification using gait and HAR features”, Pattern Recognition, Vol. 172, 112627, 2026. Paper

2025

• D. Freire-Obregón, J. Sálas-Cáceres, J. Lorenzo-Navarro, O. J. Santana, D. Hernández-Sosa, M. Castrillón-Santana, “Modeling Cultural Bias in Facial Expression Recognition with Adaptive Agents”, International Symposium on Agentic Artificial Intelligence Systems (AAIS), FLLM, 2025. Paper · Code · Slides
• D. Freire-Obregón, “Wrong Face, Wrong Move: The Social Dynamics of Emotion Misperception in Agent-Based Models”, International Workshop on Agent-Based Modelling of Human Behaviour (ABMHuB’25), ALIFE, 2025. Paper · Workshop · Slides
• D. Freire-Obregón, “Fading Faces: When Agents Forget Who You Are”, International Workshop on Mortal Agents: Physical, Psychological, and Social Death in the Machine, ALIFE, 2025. Paper · Workshop · Slides
• D. Freire-Obregón, A. Dubiel, P. K. Vinodkumar, G. Anbarjafari, D. Kamińska, M. Castrillón-Santana, “Mapping Emotions in the Brain: A Bi-Hemispheric Neural Model with Explainable Deep Learning”, International Conference on Image Analysis and Processing (ICIAP), Workshop on Neuro-Inspired AI, 2025. Paper
• D. Freire-Obregón, O. J. Santana, J. Lorenzo-Navarro, D. Hernández-Sosa, M. Castrillón-Santana, “Predicting Soccer Penalty Kick Direction Using Human Action Recognition”, International Conference on Image Analysis and Processing (ICIAP), 2025. Paper
• D. Tomašević, B. Špacapan, A. Perušić, D. Pinčić, B. Meden, D. Freire-Obregón, Ž. Emeršič, V. Štruc, P. Peer, D. Sušanj, “SynPalms: Palm Identification with Synthetic Data”, Sixteenth International Conference on Ubiquitous and Future Networks (ICUFN), 2025. DOI
• I. Rodríguez-Moreno, D. Freire-Obregón, J. M. Martínez-Otzeta, M. Castrillón-Santana, “Real-Time Hand Gesture Recognition: Lightweight Keypoint-Based Approach with Medoid Similarity”, Journal of Advances in Information Technology, Vol. 16, No. 4, pp. 447–457, 2025. Paper
• D. Freire-Obregón, J. Neves, Ž. Emeršič, B. Meden, M. Castrillón-Santana, H. Proença, “Synthesizing multilevel abstraction ear sketches for enhanced biometric recognition”, Image and Vision Computing, 2025. Paper
• D. Freire-Obregón, O. J. Santana Jaria, “La revolución de los bocetos: del trazo a mano a la inteligencia artificial”, The Conversation, 2025. Spanish · Portuguese

2024

• D. Freire-Obregón, D. Hernández-Sosa, O. J. Santana, J. Lorenzo-Navarro, M. Castrillón-Santana, “Towards Bi-Hemispheric Emotion Mapping through EEG: A Dual-Stream Neural Network Approach”, 2024 IEEE 18th International Conference on Automatic Face and Gesture Recognition (FG), 2024. Paper Arxiv
• O. J. Santana, J. Lorenzo-Navarro, D. Freire-Obregón, D. Hernández-Sosa, M. Castrillón-Santana, “Applying deep learning image enhancement methods to improve person re-identification”, Neurocomputing, 2024. Paper
• M. Castrillón-Santana, E. Sánchez-Nielsen, D. Freire-Obregón, O. J. Santana, D. Hernández-Sosa, J. Lorenzo-Navarro, “Visual Question Answering Models for Zero-Shot Pedestrian Attribute Recognition: A Comparative Study”, SN Computer Science, 2024. Paper
• F. Narducci, P. Dondi, D. Freire-Obregón (Guest Editor), F. Pop, “Introduction to the special issue on “Computer vision solutions for part-based image analysis and classification (CV_PARTIAL)””, Pattern Recognition Letters, 2024. Link
• J. Salas-Cáceres, J. Lorenzo-Navarro, D. Freire-Obregón, M. Castrillón-Santana, “Multimodal emotion recognition based on a fusion of audiovisual information with temporal dynamics”, Multimedia Tools and Applications, 2024. Paper
• M. Castrillón-Santana, D. Freire-Obregón, D. Hernández-Sosa, O. J. Santana, F. Ortega-Zamorano, J. Isern-González, J. Lorenzo-Navarro, “An Evaluation of General-Purpose Optical Character Recognizers and Digit Detectors for Race Bib Number Recognition”, ICPRAM, 2024. Paper
• D. Freire-Obregón, P. Barra, M. Castrillón-Santana, M. De Marsico, “Exploring biometric domain adaptation in human action recognition models for unconstrained environments”, Multimedia Tools and Applications, 2024. Paper

2023

• D. Freire-Obregón, J. Lorenzo-Navarro, O. J. Santana, D. Hernández-Sosa, M. Castrillón-Santana, “A Large-scale Analysis of Athletes’ Cumulative Race Time in Running Events”, International Conference on Image Analysis and Processing, 2023. Paper
• M. Castrillón-Santana, E. Sánchez-Nielsen, D. Freire-Obregón, O. J. Santana, D. Hernández-Sosa, J. Lorenzo-Navarro, “Evaluation of a visual question answering architecture for pedestrian attribute recognition”, International Conference on Computer Analysis of Images and Patterns, 2023. Paper
• J. Salas-Cáceres, J. Lorenzo-Navarro, D. Freire-Obregón, M. Castrillón-Santana, “Novelty Detection in Human-Machine Interaction Through a Multimodal Approach”, Iberoamerican Congress on Pattern Recognition, 2023. Paper
• J. Torón-Artiles, D. Hernández-Sosa, O. J. Santana, J. Lorenzo-Navarro, D. Freire-Obregón, “Classifying Soccer Ball-on-Goal Position Through Kicker Shooting Action”, arXiv preprint arXiv:2312.15236, 2023. Paper
• D. Freire-Obregón, J. Lorenzo-Navarro, O. J. Santana, D. Hernández-Sosa, M. Castrillón-Santana, “A large-scale re-identification analysis in sporting scenarios: The Betrayal of Reaching a Critical Point”, 2023 IEEE International Joint Conference on Biometrics (IJCB), 2023. Paper
• S. Almonacid-Uribe, O. J. Santana, D. Hernández-Sosa, D. Freire-Obregón, “Exploring Data Augmentation Strategies for Diagonal Earlobe Crease Detection”, International Conference on Pattern Recognition Applications and Methods, 2023. Paper
• O. J. Santana, J. Lorenzo-Navarro, D. Freire-Obregón, D. Hernández-Sosa, M. Castrillón-Santana, “Improving Person Re-identification Through Low-Light Image Enhancement”, International Conference on Pattern Recognition Applications and Methods, 2023. Paper
• L. Cimmino, D. Freire-Obregón, A. F. Abate, “Image Similarity between Masked and Unmasked Face for Consumer Electronics Applications”, 2023 IEEE International Conference on Consumer Electronics (ICCE), 2023. Paper
• O. J. Santana, J. Lorenzo-Navarro, D. Freire-Obregón, D. Hernández-Sosa, M. Castrillón-Santana, “Evaluating the Impact of Low-Light Image Enhancement Methods on Runner Re-Identification in the Wild”, ICPRAM, 2023. Paper
• D. Freire-Obregón, J. Lorenzo-Navarro, O. J. Santana, D. Hernández-Sosa, M. Castrillón-Santana, “An X3D neural network analysis for runner’s performance assessment in a wild sporting environment”, 2023 18th International Conference on Machine Vision and Applications (MVA), 2023. Paper
• F. Narducci, D. Freire-Obregón (Guest Editor), I. Passero, “Pattern Recognition for Adaptive User Interfaces”, Multimedia Tools and Applications, 2023. Link
• D. Freire-Obregón, D. Hernández-Sosa, O. J. Santana, J. Lorenzo-Navarro, M. Castrillón-Santana, “Towards facial expression robustness in multi-scale wild environments”, International conference on image analysis and processing, 2023. Paper
• D. Freire-Obregón, M. De Marsico, P. Barra, J. Lorenzo-Navarro, M. Castrillón-Santana, “Zero-shot ear cross-dataset transfer for person recognition on mobile devices”, Pattern Recognition Letters, 2023. Paper
• O. J. Santana, D. Freire-Obregón, D. Hernández-Sosa, J. Lorenzo-Navarro, E. Sánchez-Nielsen, M. Castrillón-Santana, “Facial expression analysis in a wild sporting environment”, Multimedia Tools and Applications, 2023. Paper

2022

• D. Freire-Obregón, P. Barra, M. Castrillón-Santana, M. De Marsico, “Inflated 3D ConvNet context analysis for violence detection”, Machine Vision and Applications, 2022. Paper
• S. L. Almonacid-Uribe, O. J. Santana, D. Hernández-Sosa, D. Freire-Obregón, “Deep learning for diagonal earlobe crease detection”, International Conference on Pattern Recognition Applications and Methods, 2022. Paper
• M. A. Medina, J. Lorenzo-Navarro, D. Freire-Obregón, O. J. Santana, D. Hernández-Sosa, M. Castrillón-Santana, “Boosting Re-identification in the Ultra-running Scenario”, International Conference on Pattern Recognition Applications and Methods, 2022. Paper
• D. Freire-Obregón, J. Lorenzo-Navarro, O. J. Santana, D. Hernández-Sosa, M. Castrillón-Santana, “Towards cumulative race time regression in sports: I3D ConvNet transfer learning in ultra-distance running events”, 2022 26th International Conference on Pattern Recognition (ICPR), 2022. Paper

2021

• O. J. Santana, J. Lorenzo-Navarro, D. Freire-Obregón, D. Hernández-Sosa, J. Isern-González, M. Castrillón-Santana, “Exploiting temporal coherence to improve person re-identification”, International Conference on Pattern Recognition Applications and Methods, 2021. Paper
• P. Hernández-Carrascosa, A. Penate-Sanchez, J. Lorenzo-Navarro, D. Freire-Obregón, M. Castrillón-Santana, “TGCRBNW: A dataset for runner bib number detection (and recognition) in the wild”, 2020 25th International Conference on Pattern Recognition (ICPR), 2021. Paper
• D. Freire-Obregón, K. Rosales-Santana, P. A. Marín-Reyes, A. Penate-Sanchez, J. Lorenzo-Navarro, M. Castrillón-Santana, “Improving user verification in human-robot interaction from audio or image inputs through sample quality assessment”, Pattern recognition letters, 2021. Paper

2020

• A. Penate-Sanchez, D. Freire-Obregon, A. Lorenzo-Melian, J. Lorenzo-Navarro, M. Castrillon-Santana, “TGC20ReId: A dataset for sport event re-identification in the wild”, Pattern Recognition Letters, 2020. Paper
• D. Freire-Obregón, M. Castrillón-Santana, P. Barra, C. Bisogni, M. Nappi, “An attention recurrent model for human cooperation detection”, Computer Vision and Image Understanding, 2020. Paper

2019

• P. Barra, C. Bisogni, M. Nappi, D. Freire-Obregón, M. Castrillón-Santana, “Gender classification on 2D human skeleton”, 2019 3rd International Conference on Bio-engineering for Smart Technologies (BioSMART), 2019. Paper
• P. Barra, C. Bisogni, M. Nappi, D. Freire-Obregón, M. Castrillón-Santana, “Gait analysis for gender classification in forensics”, Dependability in Sensor, Cloud, and Big Data Systems and Applications: 5th International Conference, DependSys 2019, Guangzhou, China, November 12–15, 2019, Proceedings 5, 2019. Paper
• P. Barra, C. Bisogni, M. Nappi, D. Freire-Obregón, M. Castrillón-Santana, “Gotcha-i: a multiview human videos dataset”, International Symposium on Security in Computing and Communication, 2019. Paper
• D. Freire-Obregón, F. Narducci, S. Barra, M. Castrillon-Santana, “Deep learning for source camera identification on mobile devices”, Pattern Recognition Letters, 2019. Paper

2018

• M. Castrillón-Santana, J. Lorenzo-Navarro, C. M. Travieso-González, D. Freire-Obregón, J. B. Alonso-Hernandez, “Evaluation of local descriptors and CNNs for non-adult detection in visual content”, Pattern Recognition Letters, 2018. Paper

2016

• D. Freire-Obregón, M. Castrillón-Santana, J. Lorenzo-Navarro, “Optimized clothes segmentation to boost gender classification in unconstrained scenarios”, arXiv preprint arXiv:1611.03999, 2016. Paper
• M. Castrillón-Santana, J. J. Lorenzo Navarro, D. Freire-Obregón, “Análisis de descriptores locales para la detección de menores en imágenes”, 2016. Paper
• D. Freire-Obregón, M. Castrillón-Santana, O. Déniz-Suárez, “Digital signature: a novel adaptative image segmentation approach”, Biometric Systems, Design and Applications, 2016. Paper

2015

• J. Lorenzo-Navarro, M. Castrillón-Santana, D. Freire-Obregón, E. Ramón-Balmaseda, “Stripe based clothes segmentation”, 2015 IEEE International Conference on Multimedia & Expo Workshops (ICMEW), 2015. Paper

2014

• D. Freire-Obregón, M. Castrillón-Santana, “An Evolutive Approach for Smile Recognition in Video Sequences”, International Journal of Pattern Recognition and Artificial Intelligence, 2014. Paper
• J. Lorenzo-Navarro, M. Castrillón-Santana, E. Ramón-Balmaseda, D. Freire-Obregón, “Evaluation of LBP and HOG Descriptors for Clothing Attribute Description”, Video Analytics for Audience Measurement, 2014. Paper
• D. Freire-Obregón, M. Castrillón-Santana, E. Ramón-Balmaseda, J. Lorenzo-Navarro, “Automatic clothes segmentation for soft biometrics”, 2014 IEEE International Conference on Image Processing (ICIP), 2014. Paper
• D. Freire Obregón, “Sobre la descripción visual automática del ser humano para aplicaciones de interacción hombre-máquina”, PhD Thesis, 2014. Paper

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