Juan Leon Alcazar

dblp:239/4960 · also Juan Carlos León Alcázar, Juan León Alcázar · DBLP profile ↗
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10ranked-venue papers
5as first author
9since 2021 · last 2024
0000-0002-7546-3531ORCID · corroborated

Domains — the database's venue-derived domains; a paper can count in several

Artificial intelligence and machine learning · 9 · 4 first-author · 8 since 2021Graphics, computer vision, multimedia, augmented reality and games · 9 · 4 first-author · 8 since 2021
YearPublicationVenuePosition
2024 Learning to Read Analog Gauges from Synthetic Data
abstract
Manually reading and logging gauge data is time-inefficient, and the effort increases according to the number of gauges available. We present a pipeline that automates the reading of analog gauges. We propose a two-stage CNN pipeline that identifies the key structural components of an analog gauge and outputs an angular reading. To facilitate the training of our approach, a synthetic dataset is generated thus obtaining a set of realistic analog gauges with their corresponding annotation. To validate our proposal, an additional real-world dataset was collected with 4.813 manually curated images. When compared against state-of-the-art methodologies, our method shows a significant improvement of 4.55◦in the average error, which is a 52% relative improvement. The resources for this project will be made available at: https://github.com/fuankarion/automatic-gauge-reading.
Juan Leon Alcazar, Yazeed Alnumay, Cheng Zheng 0003, Hassane Trigui, Sahejad Patel, Bernard Ghanem
WACV1
2023 PIVOT: Prompting for Video Continual Learning
abstract
Modern machine learning pipelines are limited due to data availability, storage quotas, privacy regulations, and expensive annotation processes. These constraints make it difficult or impossible to train and update large-scale models on such dynamic annotated sets. Continual learning directly approaches this problem, with the ultimate goal of devising methods where a deep neural network effectively learns relevant patterns for new (unseen) classes, without significantly altering its performance on previously learned ones. In this paper, we address the problem of continual learning for video data. We introduce PIVOT, a novel method that leverages extensive knowledge in pre-trained models from the image domain, thereby reducing the number of trainable parameters and the associated forgetting. Unlike previous methods, ours is the first approach that effectively uses prompting mechanisms for continual learning without any in-domain pre-training. Our experiments show that PIVOT improves state-of-the-art methods by a significant 27% on the 20-task ActivityNet setup.
Andrés Villa, Juan Leon Alcazar, Motasem Alfarra, Kumail Alhamoud, Julio Hurtado, Fabian Caba Heilbron, Alvaro Soto, Bernard Ghanem
CVPR2
2022 MAD: A Scalable Dataset for Language Grounding in Videos from Movie Audio Descriptions
abstract
The recent and increasing interest in video-language research has driven the development of large-scale datasets that enable data-intensive machine learning techniques. In comparison, limited effort has been made at assessing the fitness of these datasets for the video-language grounding task. Recent works have begun to discover significant limitations in these datasets, suggesting that state-of-the-art techniques commonly overfit to hidden dataset biases. In this work, we present MAD (Movie Audio Descriptions), a novel benchmark that departs from the paradigm of augmenting existing video datasets with text annotations and focuses on crawling and aligning available audio descriptions of mainstream movies. MAD contains over 384, 000 natural language sentences grounded in over 1, 200 hours of videos and exhibits a significant reduction in the currently diagnosed biases for video-language grounding datasets. MAD's collection strategy enables a novel and more challenging version of video-language grounding, where short temporal moments (typically seconds long) must be accurately grounded in diverse long-form videos that can last up to three hours. We have released MAD's data and baselines code at https://github.com/Soldelli/MAD.
Mattia Soldan, Alejandro Pardo, Juan Leon Alcazar, Fabian Caba Heilbron, Chen Zhao 0002, Silvio Giancola, Bernard Ghanem
CVPR3
2022 vCLIMB: A Novel Video Class Incremental Learning Benchmark
abstract
Continual learning (CL) is under-explored in the video domain. The few existing works contain splits with imbalanced class distributions over the tasks, or study the problem in unsuitable datasets. We introduce vCLIMB, a novel video continual learning benchmark. vCLIMB is a standardized test-bed to analyze catastrophic forgetting of deep models in video continual learning. In contrast to previous work, we focus on class incremental continual learning with models trained on a sequence of disjoint tasks, and distribute the number of classes uniformly across the tasks. We perform in-depth evaluations of existing CL methods in vCLIMB, and observe two unique challenges in video data. The selection of instances to store in episodic memory is performed at the frame level. Second, untrimmed training data influences the effectiveness of frame sampling strategies. We address these two challenges by proposing a temporal consistency regularization that can be applied on top of memory-based continual learning methods. Our approach significantly improves the baseline, by up to 24% on the untrimmed continual learning task. The code of our benchmark can be found at: https://vclimb.netlify.app/.
Andrés Villa, Kumail Alhamoud, Victor Escorcia, Fabian Caba Heilbron, Juan Leon Alcazar, Bernard Ghanem
CVPR5
2022 End-to-End Active Speaker Detection
Juan Leon Alcazar, Moritz Cordes, Chen Zhao 0002, Bernard Ghanem
ECCV (37)1
2022 MovieCuts: A New Dataset and Benchmark for Cut Type Recognition
Alejandro Pardo, Fabian Caba Heilbron, Juan Leon Alcazar, Ali K. Thabet, Bernard Ghanem
ECCV (7)3
2021 MAAS: Multi-modal Assignation for Active Speaker Detection
abstract
Active speaker detection requires a mindful integration of multi-modal cues. Current methods focus on modeling and fusing short-term audiovisual features for individual speakers, often at frame level. We present a novel approach to active speaker detection that directly addresses the multi-modal nature of the problem and provides a straightforward strategy, where independent visual features (speakers) in the scene are assigned to a previously detected speech event. Our experiments show that a small graph data structure built from local information can approximate an instantaneous audio-visual assignment problem. More-over, the temporal extension of this initial graph achieves a new state-of-the-art performance on the AVA-ActiveSpeaker dataset with a mAP of 88.8%.
Juan Leon Alcazar, Fabian Caba Heilbron, Ali K. Thabet, Bernard Ghanem
ICCV1
2021 Learning to Cut by Watching Movies
abstract
Video content creation keeps growing at an incredible pace; yet, creating engaging stories remains challenging and requires non-trivial video editing expertise. Many video editing components are astonishingly hard to automate primarily due to the lack of raw video materials. This paper focuses on a new task for computational video editing, namely the task of raking cut plausibility. Our key idea is to leverage content that has already been edited to learn fine-grained audiovisual patterns that trigger cuts. To do this, we first collected a data source of more than 10K videos, from which we extract more than 255K cuts. We devise a model that learns to discriminate between real and artificial cuts via contrastive learning. We set up a new task and a set of baselines to benchmark video cut generation. We observe that our proposed model outperforms the baselines by large margins. To demonstrate our model in real-world applications, we conduct human studies in a collection of unedited videos. The results show that our model does a better job at cutting than random and alternative baselines.
Alejandro Pardo, Fabian Caba Heilbron, Juan Leon Alcazar, Ali K. Thabet, Bernard Ghanem
ICCV3
2021 MAIN: Multi-Attention Instance Network for video segmentation
Juan Leon Alcazar, María Alejandra Bravo, Guillaume Jeanneret, Ali K. Thabet, Thomas Brox, Pablo Andrés Arbeláez, Bernard Ghanem
Comput. Vis. Image Underst.1
2020 Active Speakers in Context
abstract
Current methods for active speaker detection focus on modeling audiovisual information from a single speaker. This strategy can be adequate for addressing single-speaker scenarios, but it prevents accurate detection when the task is to identify who of many candidate speakers are talking. This paper introduces the Active Speaker Context, a novel representation that models relationships between multiple speakers over long time horizons. Our new model learns pairwise and temporal relations from a structured ensemble of audiovisual observations. Our experiments show that a structured feature ensemble already benefits active speaker detection performance. We also find that the proposed Active Speaker Context improves the state-of-the-art on the AVA-ActiveSpeaker dataset achieving an mAP of 87.1%. Moreover, ablation studies verify that this result is a direct consequence of our long-term multi-speaker analysis.
Juan Leon Alcazar, Fabian Caba Heilbron, Long Mai, Federico Perazzi, Joon-Young Lee, Pablo Andrés Arbeláez, Bernard Ghanem
CVPR1