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Publicações

Publicações por Luís Filipe Teixeira

2023

Evaluating Privacy on Synthetic Images Generated using GANs: Contributions of the VCMI Team to ImageCLEFmedical GANs 2023

Autores
Montenegro, H; Neto, PC; Patrício, C; Torto, IR; Gonçalves, T; Teixeira, LF;

Publicação
Working Notes of the Conference and Labs of the Evaluation Forum (CLEF 2023), Thessaloniki, Greece, September 18th to 21st, 2023.

Abstract
This paper presents the main contributions of the VCMI Team to the ImageCLEFmedical GANs 2023 task. This task aims to evaluate whether synthetic medical images generated using Generative Adversarial Networks (GANs) contain identifiable characteristics of the training data. We propose various approaches to classify a set of real images as having been used or not used in the training of the model that generated a set of synthetic images. We use similarity-based approaches to classify the real images based on their similarity to the generated ones. We develop autoencoders to classify the images through outlier detection techniques. Finally, we develop patch-based methods that operate on patches extracted from real and generated images to measure their similarity. On the development dataset, we attained an F1-score of 0.846 and an accuracy of 0.850 using an autoencoder-based method. On the test dataset, a similarity-based approach achieved the best results, with an F1-score of 0.801 and an accuracy of 0.810. The empirical results support the hypothesis that medical data generated using deep generative models trained without privacy constraints threatens the privacy of patients in the training data. © 2023 Copyright for this paper by its authors.

2024

TOWARDS CONCEPT-BASED INTERPRETABILITY OF SKIN LESION DIAGNOSIS USING VISION-LANGUAGE MODELS

Autores
Patricio, C; Teixeira, LF; Neves, JC;

Publicação
IEEE INTERNATIONAL SYMPOSIUM ON BIOMEDICAL IMAGING, ISBI 2024

Abstract
Concept-based models naturally lend themselves to the development of inherently interpretable skin lesion diagnosis, as medical experts make decisions based on a set of visual patterns of the lesion. Nevertheless, the development of these models depends on the existence of concept-annotated datasets, whose availability is scarce due to the specialized knowledge and expertise required in the annotation process. In this work, we show that vision-language models can be used to alleviate the dependence on a large number of concept-annotated samples. In particular, we propose an embedding learning strategy to adapt CLIP to the downstream task of skin lesion classification using concept-based descriptions as textual embeddings. Our experiments reveal that vision-language models not only attain better accuracy when using concepts as textual embeddings, but also require a smaller number of concept-annotated samples to attain comparable performance to approaches specifically devised for automatic concept generation.

2022

Pattern Recognition and Image Analysis

Autores
Pinho, AJ; Georgieva, P; Teixeira, LF; Sánchez, JA;

Publicação
Lecture Notes in Computer Science

Abstract

2024

Explainable Deep Learning Methods in Medical Image Classification: A Survey

Autores
Patrício, C; Neves, C; Teixeira, F;

Publicação
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.

2023

MobileWeatherNet for LiDAR-Only Weather Estimation

Autores
da Silva, MP; Carneiro, D; Fernandes, J; Texeira, LF;

Publicação
2023 INTERNATIONAL JOINT CONFERENCE ON NEURAL NETWORKS, IJCNN

Abstract
An autonomous vehicle relying on LiDAR data should be able to assess its limitations in real time without depending on external information or additional sensors. The point cloud generated by the sensor is subjected to significant degradation under adverse weather conditions (rain, fog, and snow), which limits the vehicle's visibility and performance. With this in mind, we show that point cloud data contains sufficient information to estimate the weather accurately and present MobileWeatherNet, a LiDAR-only convolutional neural network that uses the bird's-eye view 2D projection to extract point clouds' weather condition and improves state-of-the-art performance by 15% in terms of the balanced accuracy while reducing inference time by 63%. Moreover, this paper demonstrates that among common architectures, the use of the bird's eye view significantly enhances their performance without an increase in complexity. To the extent of our knowledge, this is the first approach that uses deep learning for weather estimation using point cloud data in the form of a bird's-eye-view projection.

2012

Designing tablet-based games for seniors: the example of CogniPlay, a cognitive gaming platform

Autores
Vasconcelos, A; Silva, PA; Caseiro, J; Nunes, F; Teixeira, LF;

Publicação
Proceedings of the 4th International Conference on Fun and Games, Fun and Games 2012, Toulouse, France, September 4-6, 2012

Abstract
This paper describes the analysis and design of a tablet-based gaming platform for seniors that promotes their quality-of-life and well-being by incorporating cognitive training mechanisms. A literature review of age-related changes and games for seniors indicated 'casual games' have the characteristics necessary to provide an enjoyable user experience for the senior audience. Having concluded that these games should target cognitive stimulation, the authors analysed mechanisms to achieve this purpose and compiled them into a matrix to be used as a starting point for the games design process. In parallel, the authors also gathered seniors' preferences and requirements regarding games, through observations and a game book. Low-, medium-, and high-fidelity prototypes for a gaming cognitive platform were developed, evaluated with end-users, and iteratively improved. Results showed that seniors easily interacted with the platform and were willing to use it in the future. Results and experience led to the identification of 10 rules of thumb that can be beneficial if applied to related projects. This paper concludes by identifying exciting areas for future research and development. © 2012 ACM.

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