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Publications

Publications by João Tiago Pinto

2021

Secure Triplet Loss: Achieving Cancelability and Non-Linkability in End-to-End Deep Biometrics

Authors
Pinto, JR; Correia, MV; Cardoso, JS;

Publication
IEEE Trans. Biom. Behav. Identity Sci.

Abstract

2020

Audiovisual Classification of Group Emotion Valence Using Activity Recognition Networks

Authors
Pinto, JR; Gonçalves, T; Pinto, C; Sanhudo, L; Fonseca, J; Gonçalves, F; Carvalho, P; Cardoso, JS;

Publication
4th IEEE International Conference on Image Processing, Applications and Systems, IPAS 2020, Virtual Event, Italy, December 9-11, 2020

Abstract
Despite recent efforts, accuracy in group emotion recognition is still generally low. One of the reasons for these underwhelming performance levels is the scarcity of available labeled data which, like the literature approaches, is mainly focused on still images. In this work, we address this problem by adapting an inflated ResNet-50 pretrained for a similar task, activity recognition, where large labeled video datasets are available. Audio information is processed using a Bidirectional Long Short-Term Memory (Bi-LSTM) network receiving extracted features. A multimodal approach fuses audio and video information at the score level using a support vector machine classifier. Evaluation with data from the EmotiW 2020 AV Group-Level Emotion sub-challenge shows a final test accuracy of 65.74% for the multimodal approach, approximately 18% higher than the official baseline. The results show that using activity recognition pretraining offers performance advantages for group-emotion recognition and that audio is essential to improve the accuracy and robustness of video-based recognition. © 2020 IEEE.

2021

ECG Biometrics

Authors
Pinto, JR; Cardoso, JS;

Publication
Encyclopedia of Cryptography, Security and Privacy

Abstract

2021

Mixture-Based Open World Face Recognition

Authors
Matta, A; Pinto, JR; Cardoso, JS;

Publication
Trends and Applications in Information Systems and Technologies - Volume 3, WorldCIST 2021, Terceira Island, Azores, Portugal, 30 March - 2 April, 2021.

Abstract
Face Recognition (FR) is a challenging task, especially when dealing with unknown identities. While Open-Set Face Recognition (OSFR) assigns a single class to all unfamiliar subjects, Open-World Face Recognition (OWFR) employs an incremental approach, creating a new class for each unknown individual. Current OWFR approaches still present limitations, mainly regarding the accuracy gap to standard closed-set approaches and execution time. This paper proposes a fast and simple mixture-based OWFR algorithm that tackles the execution time issue while avoiding accuracy decay. The proposed method uses data curve representations and Universal Background Models based on Gaussian Mixture Models. Experimental results show that the proposed approach achieves competitive performance, considering accuracy and execution time, in both closed-set and open-world scenarios. © 2021, The Author(s), under exclusive license to Springer Nature Switzerland AG.

2021

MFR 2021: Masked Face Recognition Competition

Authors
Boutros, F; Damer, N; Kolf, JN; Raja, K; Kirchbuchner, F; Ramachandra, R; Kuijper, A; Fang, PC; Zhang, C; Wang, F; Montero, D; Aginako, N; Sierra, B; Nieto, M; Erakin, ME; Demir, U; Ekenel, HK; Kataoka, A; Ichikawa, K; Kubo, S; Zhang, J; He, MJ; Han, D; Shan, SG; Grm, K; Struc, V; Seneviratne, S; Kasthuriarachchi, N; Rasnayaka, S; Neto, PC; Sequeira, AF; Pinto, JR; Saffari, M; Cardoso, JS;

Publication
2021 INTERNATIONAL JOINT CONFERENCE ON BIOMETRICS (IJCB 2021)

Abstract
This paper presents a summary of the Masked Face Recognition Competitions (MFR) held within the 2021 International Joint Conference on Biometrics (IJCB 2021). The competition attracted a total of 10 participating teams with valid submissions. The affiliations of these teams are diverse and associated with academia and industry in nine different countries. These teams successfully submitted 18 valid solutions. The competition is designed to motivate solutions aiming at enhancing the face recognition accuracy of masked faces. Moreover, the competition considered the deployability of the proposed solutions by taking the compactness of the face recognition models into account. A private dataset representing a collaborative, multi-session, real masked, capture scenario is used to evaluate the submitted solutions. In comparison to one of the top-performing academic face recognition solutions, 10 out of the 18 submitted solutions did score higher masked face verification accuracy.

2021

Impact of Visual Noise in Activity Recognition Using Deep Neural Networks - An Experimental Approach

Authors
Capozzi, L; Carvalho, P; Sousa, A; Pinto, C; Pinto, JR; Cardoso, JS;

Publication
2021 IEEE 2nd International Conference on Pattern Recognition and Machine Learning, PRML 2021

Abstract
The popularity of deep learning methods has increased significantly, in no small part due to their impressive performance in several application scenarios. This paper focuses on recognising activities in an in-vehicle environment and measuring the impact that factors such as resolution, aspect ratio, field of view and framerate have on the performance of the model. The use of deep learning methodologies in recent years has increased the amount of data required to train and test the models. However, such data is often insufficient, unavailable, or lacks suitable properties. Publicly available action recognition datasets have been analysed, collected, and prepared to assess the classification results in such scenarios, which provides important guidance for use in a real-world setting. © 2021 IEEE.

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