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Publicações

2024

Image Stitching of Low-Resolution Retinography Using Fundus Blur Filter and Homography Convolutional Neural Network

Autores
Santos, L; Almeida, M; Almeida, J; Braz, G; Camara, J; Cunha, A;

Publicação
INFORMATION

Abstract
Great advances in stitching high-quality retinal images have been made in recent years. On the other hand, very few studies have been carried out on low-resolution retinal imaging. This work investigates the challenges of low-resolution retinal images obtained by the D-EYE smartphone-based fundus camera. The proposed method uses homography estimation to register and stitch low-quality retinal images into a cohesive mosaic. First, a Siamese neural network extracts features from a pair of images, after which the correlation of their feature maps is computed. This correlation map is fed through four independent CNNs to estimate the homography parameters, each specializing in different corner coordinates. Our model was trained on a synthetic dataset generated from the Microsoft Common Objects in Context (MSCOCO) dataset; this work added an important data augmentation phase to improve the quality of the model. Then, the same is evaluated on the FIRE retina and D-EYE datasets for performance measurement using the Peak Signal-to-Noise Ratio (PSNR) and Structural Similarity Index (SSIM). The obtained results are promising: the average PSNR was 26.14 dB, with an SSIM of 0.96 on the D-EYE dataset. Compared to the method that uses a single neural network for homography calculations, our approach improves the PSNR by 7.96 dB and achieves a 7.86% higher SSIM score.

2024

Collaborative learning using open-source FPGA-based under water ultrasonic system

Autores
Lemaire, E; Busseuil, R; Chemla, J; Certon, D; Zambelli, C; Cruz de la Torre, C; Gardel Vicente, A; Bravo, I; Mendonça, H; Alves, JC;

Publicação

Abstract
The Digital electronics collaborative enhanced learning (DECEL) project has recently developed an international collaborative education course. Its main objective is to enhance the digital electronics skills of international students by working on a complex, multidisciplinary applied problem using a mixed digital architecture. We have developed a logic level synthesis and dedicated software layers on the Red Pitaya FPGA platform. The diversity of digital concepts to be implemented, from hardware description language (HDL) to high-level languages such as Python or Matlab, forced the students to work together and rapidly improve their skills. Their motivation was fueled by the curiosity of controlling an ultrasound probe to obtain ultrasound signatures. This particular physics, little known to the students, was an additional source of curiosity. The goal of forming an image in a liquid medium was an additional motivating factor for them. The students reported that they learned a lot from the experiment. Thus, the technical parts and pedagogical results are documented in this work for reproducibility.

2024

Unleash the Power of Engineering Questions

Autores
Harrison, NB; Aguiar, A;

Publicação
RESEARCH CHALLENGES IN INFORMATION SCIENCE, PT II, RCIS 2024

Abstract
This tutorial delves into the transformative power of asking effective questions in engineering information systems. We explore how crafting well-defined questions in both the problem space (what issue are we addressing?) and the solution space (how will we approach it?) is paramount for success. The session will unveil the intricate relationship between these questions - how the what shapes the how and vice versa. We move beyond the fear of asking naive questions, demonstrating how these can spark innovation and reveal hidden assumptions. By the end, attendees will have a powerful and easy-to-use technique that removes the fear from questions.

2024

Network-secure aggregator operating regions with flexible dispatch envelopes in unbalanced systems

Autores
Russell, JS; Scott, P; Iria, J;

Publicação
Electric Power Systems Research

Abstract

2024

Brand Love, Attitude, and Environmental Cause Knowledge: Sustainable Blue Jeans Consumer Behavior

Autores
Magano, J; Brandao, T; Delgado, C; Vale, V;

Publicação
SUSTAINABILITY

Abstract
A blue jeans brand committed to the environmental cause could position itself as unique and socially responsible and attract environmentally driven consumers. This research study examines the relationship between brand love and consumers' environmental cause knowledge and their willingness to recommend and pay a premium for sustainable blue jeans. To this end, this cross-sectional study comprises a snowball convenience sample of 978 Portuguese respondents, whose data were collected from December 2022 to January 2023. Positive associations between self-expression, brand love, loyalty, environmental cause knowledge, positive word-of-mouth, and willingness to pay a premium for sustainable blue jeans stand out. There are differences in the willingness to pay a premium among generations, education levels, and consumers who are aware of sustainable line extensions and those who are not. The results may be helpful for brands, suggesting their communication should focus on creating increased proximity to consumers by enhancing their values and seeking to link their brands to intrinsic benefits and environmental stakes. This is the first study to incorporate knowledge of the environmental cause into a model linking brand love, brand loyalty, positive word-of-mouth, and willingness to pay a premium for sustainable blue jeans.

2024

Chestnut Burr Segmentation for Yield Estimation Using UAV-Based Imagery and Deep Learning

Autores
Carneiro, GA; Santos, J; Sousa, JJ; Cunha, A; Pádua, L;

Publicação
DRONES

Abstract
Precision agriculture (PA) has advanced agricultural practices, offering new opportunities for crop management and yield optimization. The use of unmanned aerial vehicles (UAVs) in PA enables high-resolution data acquisition, which has been adopted across different agricultural sectors. However, its application for decision support in chestnut plantations remains under-represented. This study presents the initial development of a methodology for segmenting chestnut burrs from UAV-based imagery to estimate its productivity in point cloud data. Deep learning (DL) architectures, including U-Net, LinkNet, and PSPNet, were employed for chestnut burr segmentation in UAV images captured at a 30 m flight height, with YOLOv8m trained for comparison. Two datasets were used for training and to evaluate the models: one newly introduced in this study and an existing dataset. U-Net demonstrated the best performance, achieving an F1-score of 0.56 and a counting accuracy of 0.71 on the proposed dataset, using a combination of both datasets during training. The primary challenge encountered was that burrs often tend to grow in clusters, leading to unified regions in segmentation, making object detection potentially more suitable for counting. Nevertheless, the results show that DL architectures can generate masks for point cloud segmentation, supporting precise chestnut tree production estimation in future studies.

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