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About

About

Luis F. Teixeira holds a Ph.D. in Electrical and Computer Engineering from Universidade do Porto in computer vision (2009). Currently, he is an Associate Professor at the Department of Informatics Engineering, Faculdade de Engenharia da Universidade do Porto, and a researcher at INESC TEC. Previously, he was a researcher at INESC Porto (2001-2008), a Visiting Researcher at the University of Victoria (2006), and a Senior Scientist at Fraunhofer AICOS (2008-2013). His current research interests include computer vision, machine learning and interactive systems.

Interest
Topics
Details

Details

  • Name

    Luís Filipe Teixeira
  • Role

    Senior Researcher
  • Since

    17th September 2001
006
Publications

2025

Multimodal PointPillars for Efficient Object Detection in Autonomous Vehicles

Authors
Oliveira, M; Cerqueira, R; Pinto, JR; Fonseca, J; Teixeira, LF;

Publication
IEEE Trans. Intell. Veh.

Abstract
Autonomous Vehicles aim to understand their surrounding environment by detecting relevant objects in the scene, which can be performed using a combination of sensors. The accurate prediction of pedestrians is a particularly challenging task, since the existing algorithms have more difficulty detecting small objects. This work studies and addresses this often overlooked problem by proposing Multimodal PointPillars (M-PP), a fast and effective novel fusion architecture for 3D object detection. Inspired by both MVX-Net and PointPillars, image features from a 2D CNN-based feature map are fused with the 3D point cloud in an early fusion architecture. By changing the heavy 3D convolutions of MVX-Net to a set of convolutional layers in 2D space, along with combining LiDAR and image information at an early stage, M-PP considerably improves inference time over the baseline, running at 28.49 Hz. It achieves inference speeds suitable for real-world applications while keeping the high performance of multimodal approaches. Extensive experiments show that our proposed architecture outperforms both MVX-Net and PointPillars for the pedestrian class in the KITTI 3D object detection dataset, with 62.78% in $AP_{BEV}$ (moderate difficulty), while also outperforming MVX-Net in the nuScenes dataset. Moreover, experiments were conducted to measure the detection performance based on object distance. The performance of M-PP surpassed other methods in pedestrian detection at any distance, particularly for faraway objects (more than 30 meters). Qualitative analysis shows that M-PP visibly outperformed MVX-Net for pedestrians and cyclists, while simultaneously making accurate predictions of cars.

2025

Markerless multi-view 3D human pose estimation: A survey

Authors
Nogueira, AFR; Oliveira, HP; Teixeira, LF;

Publication
IMAGE AND VISION COMPUTING

Abstract
3D human pose estimation aims to reconstruct the human skeleton of all the individuals in a scene by detecting several body joints. The creation of accurate and efficient methods is required for several real-world applications including animation, human-robot interaction, surveillance systems or sports, among many others. However, several obstacles such as occlusions, random camera perspectives, or the scarcity of 3D labelled data, have been hampering the models' performance and limiting their deployment in real-world scenarios. The higher availability of cameras has led researchers to explore multi-view solutions due to the advantage of being able to exploit different perspectives to reconstruct the pose. Most existing reviews focus mainly on monocular 3D human pose estimation and a comprehensive survey only on multi-view approaches to determine the 3D pose has been missing since 2012. Thus, the goal of this survey is to fill that gap and present an overview of the methodologies related to 3D pose estimation in multi-view settings, understand what were the strategies found to address the various challenges and also, identify their limitations. According to the reviewed articles, it was possible to find that most methods are fully-supervised approaches based on geometric constraints. Nonetheless, most of the methods suffer from 2D pose mismatches, to which the incorporation of temporal consistency and depth information have been suggested to reduce the impact of this limitation, besides working directly with 3D features can completely surpass this problem but at the expense of higher computational complexity. Models with lower supervision levels were identified to overcome some of the issues related to 3D pose, particularly the scarcity of labelled datasets. Therefore, no method is yet capable of solving all the challenges associated with the reconstruction of the 3D pose. Due to the existing trade-off between complexity and performance, the best method depends on the application scenario. Therefore, further research is still required to develop an approach capable of quickly inferring a highly accurate 3D pose with bearable computation cost. To this goal, techniques such as active learning, methods that learn with a low level of supervision, the incorporation of temporal consistency, view selection, estimation of depth information and multi-modal approaches might be interesting strategies to keep in mind when developing a new methodology to solve this task.

2025

A two-step concept-based approach for enhanced interpretability and trust in skin lesion diagnosis

Authors
Patrício, C; Teixeira, LF; Neves, JC;

Publication
COMPUTATIONAL AND STRUCTURAL BIOTECHNOLOGY JOURNAL

Abstract
The main challenges hindering the adoption of deep learning-based systems in clinical settings are the scarcity of annotated data and the lack of interpretability and trust in these systems. Concept Bottleneck Models (CBMs) offer inherent interpretability by constraining the final disease prediction on a set of human-understandable concepts. However, this inherent interpretability comes at the cost of greater annotation burden. Additionally, adding new concepts requires retraining the entire system. In this work, we introduce a novel two-step methodology that addresses both of these challenges. By simulating the two stages of a CBM, we utilize a pretrained Vision Language Model (VLM) to automatically predict clinical concepts, and an off-the-shelf Large Language Model (LLM) to generate disease diagnoses grounded on the predicted concepts. Furthermore, our approach supports test-time human intervention, enabling corrections to predicted concepts, which improves final diagnoses and enhances transparency in decision-making. We validate our approach on three skin lesion datasets, demonstrating that it outperforms traditional CBMs and state-of-the-art explainable methods, all without requiring any training and utilizing only a few annotated examples. The code is available at https://github.com/CristianoPatricio/2step-concept-based-skin-diagnosis.

2025

CBVLM: Training-free Explainable Concept-based Large Vision Language Models for Medical Image Classification

Authors
Patrício, C; Torto, IR; Cardoso, JS; Teixeira, LF; Neves, JC;

Publication
CoRR

Abstract

2024

Explainable Deep Learning Methods in Medical Image Classification: A Survey

Authors
Patrício, C; Neves, C; Teixeira, F;

Publication
ACM COMPUTING SURVEYS

Abstract
The remarkable success of deep learning has prompted interest in its application to medical imaging diagnosis. Even though state-of-the-art deep learning models have achieved human-level accuracy on the classification of different types of medical data, these models are hardly adopted in clinical workflows, mainly due to their lack of interpretability. The black-box nature of deep learning models has raised the need for devising strategies to explain the decision process of these models, leading to the creation of the topic of eXplainable Artificial Intelligence (XAI). In this context, we provide a thorough survey of XAI applied to medical imaging diagnosis, including visual, textual, example-based and concept-based explanation methods. Moreover, this work reviews the existing medical imaging datasets and the existing metrics for evaluating the quality of the explanations. In addition, we include a performance comparison among a set of report generation-based methods. Finally, the major challenges in applying XAI to medical imaging and the future research directions on the topic are discussed.

Supervised
thesis

2023

Unconstrained Human Pose Estimation to Support Breast Cancer Survivor's Prospective Surveillance

Author
João Pedro da Silva Monteiro

Institution
UP-FEUP

2023

Self-Supervised Learning for Medical Image Classification: A Study on MoCo-CXR

Author
Hugo Miguel Monteiro Guimarães

Institution
UP-FEUP

2023

Learning to detect defects in industrial production lines from a few examples

Author
André Filipe Vila Chã Afonso

Institution
UP-FEUP

2023

Self-explanatory computer-aided diagnosis with limited supervision

Author
Isabel Cristina Rio-Torto de Oliveira

Institution
UP-FEUP

2023

Integrating Anatomical Prior Knowledge for Increased Generalisability in Breast Cancer Multi-center Data

Author
Isabela Marques de Miranda

Institution
UP-FEUP