Ana  Beatriz Alvarez

Prof. Dr. Ana Beatriz Alvarez

CCET - Centro de Ciências Exatas e Tecnológicas, Universidade Federal do Acre, Rio Branco, Acre, Brazil
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Research Focus & Metrics

Academic Career Length

8Years (2019-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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4 July 2023 in Applied Sciences
Verified
Journal Article
Open access
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Ruben Dario Florez-ZelaRuben Dario Florez-Zela
Ruben Dario Florez-Zela
FPFacundo Palomino-Quispe
Facundo Palomino-Quispe
RCRoger Jesus Coaquira-Castillo
Roger Jesus Coaquira-Castillo
JHJulio Cesar Herrera-Levano
Julio Cesar Herrera-Levano
Thuanne PaixãoThuanne Paixão
Thuanne Paixão
Ana  Beatriz AlvarezAna Beatriz Alvarez
Ana Beatriz Alvarez
Drowsiness detection is an important task in road safety and other areas that require sustained attention. In this article, an approach to detect drowsiness in drivers is presented, focusing on the eye region, since eye fatigue is one of the first symptoms of drowsiness. The method used for the extraction of the eye region is Mediapipe, chosen for its high accuracy and robustness. Three neural networks were analyzed based on InceptionV3, VGG16 and ResNet50V2, which implement deep learning. The database used is NITYMED, which contains videos of drivers with different levels of drowsiness. The three networks were evaluated in terms of accuracy, precision and recall in detecting drowsiness in the eye region. The results of the study show that all three convolutional neural networks have high accuracy in detecting drowsiness in the eye region. In particular, the Resnet50V2 network achieved the highest accuracy, with a rate of 99.71% on average. For better visualization of the data, the Grad-CAM technique is used, with which we obtain a better understanding of the performance of the algorithms in the classification process.

27 September 2024 in Sensors
Verified
Journal Article
Open access
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Ruben Dario Florez-ZelaRuben Dario Florez-Zela
Ruben Dario Florez-Zela
FPFacundo Palomino-Quispe
Facundo Palomino-Quispe
Ana  Beatriz AlvarezAna Beatriz Alvarez
Ana Beatriz Alvarez
RCRoger Jesus Coaquira-Castillo
Roger Jesus Coaquira-Castillo
JHJulio Cesar Herrera-Levano
Julio Cesar Herrera-Levano
Currently, the number of vehicles in circulation continues to increase steadily, leading to a parallel increase in vehicular accidents. Among the many causes of these accidents, human factors such as driver drowsiness play a fundamental role. In this context, one solution to address the challenge of drowsiness detection is to anticipate drowsiness by alerting drivers in a timely and effective manner. Thus, this paper presents a Convolutional Neural Network (CNN)-based approach for drowsiness detection by analyzing the eye region and Mouth Aspect Ratio (MAR) for yawning detection. As part of this approach, endpoint delineation is optimized for extraction of the region of interest (ROI) around the eyes. An NVIDIA Jetson Nano-based device and near-infrared (NIR) camera are used for real-time applications. A Driver Drowsiness Artificial Intelligence (DD-AI) architecture is proposed for the eye state detection procedure. In a performance analysis, the results of the proposed approach were compared with architectures based on InceptionV3, VGG16, and ResNet50V2. Night-Time Yawning–Microsleep–Eyeblink–Driver Distraction (NITYMED) was used for training, validation, and testing of the architectures. The proposed DD-AI network achieved an accuracy of 99.88% with the NITYMED test data, proving superior to the other networks. In the hardware implementation, tests were conducted in a real environment, resulting in 96.55% and 14 fps on average for the DD-AI network, thereby confirming its superior performance.

14 March 2025 in Applied Sciences
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Journal Article
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EJEder Silva dos Santos Júnior
Eder Silva dos Santos Júnior
Thuanne PaixãoThuanne Paixão
Thuanne Paixão
Ana  Beatriz AlvarezAna Beatriz Alvarez
Ana Beatriz Alvarez
The digitalization of historical documents is of interest for many reasons, including historical preservation, accessibility, and searchability. One of the main challenges with the digitization of old newspapers involves complex layout analysis, where the content types of the document must be determined. In this context, this paper presents an evaluation of the most recent YOLO methods for the analysis of historical document layouts. Initially, a new dataset called BHN was created and made available, standing out as the first dataset of historical Brazilian newspapers for layout detection. The experiments were held using the YOLOv8, YOLOv9, YOLOv10, and YOLOv11 architectures. For training, validation, and testing of the models, the following historical newspaper datasets were combined: BHN, GBN, and Printed BlaLet GT. Recall, precision, and mean average precision (mAP) were used to evaluate the performance of the models. The results indicate that the best performer was YOLOv8, with a Recalltest of 81% and an mAPtest of 89%. This paper provides insights on the advantages of these models in historical document layout detection and also promotes improvement of document image conversion into editable and accessible formats.

14 March 2025 in Applied Sciences
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JBJoão Marcos Ribeiro Bento
João Marcos Ribeiro Bento
Thuanne PaixãoThuanne Paixão
Thuanne Paixão
Ana  Beatriz AlvarezAna Beatriz Alvarez
Ana Beatriz Alvarez
Stamps are an essential mechanism for authenticating documents in various sectors and institutions. Given the high volume of documents and the increase in forgery, it is necessary to adopt automated methods to identify stamps on documents. In this context, techniques based on deep learning stand out as an efficient solution for automating this process. To this end, this article presents a performance evaluation of YOLOv8s, YOLOv9s, YOLOv10s, and YOLOv11s in detecting stamps on scanned documents. To train, validate, and test the models, an adapted dataset with 732 images from the combination of the StaVer and DDI-100 datasets is used. The performance of the models is evaluated by means of quantitative and qualitative analyses and by analyzing the computational cost. The results show that, in terms of performance, the YOLOv9s model obtained the best result, with a mAP (Mean Average Precision) of 98.7% for a precision and recall of 97.6%. In terms of computational cost and shorter inference time, the YOLOv11s model stands out. This comparative approach is a contribution to the state of the art for implementation in automatic stamp authentication devices.

1 May 2025 in Applied Sciences
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JFJonatan Rodrigues Borges Fragoso
Jonatan Rodrigues Borges Fragoso
CSClécio Silva
Clécio Silva
Thuanne PaixãoThuanne Paixão
Thuanne Paixão
Ana  Beatriz AlvarezAna Beatriz Alvarez
Ana Beatriz Alvarez
OJOlacir Castro Júnior
Olacir Castro Júnior
PTPAULO ANDRÉ TRAZZI
PAULO ANDRÉ TRAZZI
Coffee cultivation is vital to the global economy, but faces significant challenges with diseases such as rust, miner, phoma, and cercospora, which impact production and sustainable crop management. In this scenario, deep learning techniques have shown promise for the early identification of these diseases, enabling more efficient monitoring. This paper proposes an approach for detecting diseases and pests on coffee leaves using an efficient single-shot object-detection algorithm. The experiments were conducted using the YOLOv8, YOLOv9, YOLOv10 and YOLOv11 versions, including their variations. The BRACOL dataset, annotated by an expert, was used in the experiments to guarantee the quality of the annotations and the reliability of the trained models. The evaluation of the models included quantitative and qualitative analyses, considering the mAP, F1-Score, and recall metrics. In the analyses, YOLOv8s stands out as the most effective, with a mAP of 54.5%, an inference time of 11.4 ms and the best qualitative predictions, making it ideal for real-time applications.

10 August 2024 in Sensors
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WPWilliam Isaac Perez-Torres
William Isaac Perez-Torres
DUDiego Armando Uman
Diego Armando Uman
AQAndres Benjamin Quispe Quispe
Andres Benjamin Quispe Quispe
FPFacundo Palomino-Quispe
Facundo Palomino-Quispe
EBEmili Silva Bezerra
Emili Silva Bezerra
Ana  Beatriz AlvarezAna Beatriz Alvarez
Ana Beatriz Alvarez
High-mountain water bodies represent critical components of their ecosystems, serving as vital freshwater reservoirs, environmental regulators, and sentinels of climate change. To understand the environmental dynamics of these regions, comprehensive analyses of lakes across spatial and temporal scales are necessary. While remote sensing offers a powerful tool for lake monitoring, applications in high-mountain terrain present unique challenges. The Ancash and Cuzco regions of the Peruvian Andes exemplify these challenges. These regions harbor numerous high-mountain lakes, which are crucial for fresh water supply and environmental regulation. This paper presents an exploratory examination of remote sensing techniques for lake monitoring in the Ancash and Cuzco regions of the Peruvian Andes. The study compares three deep learning models for lake segmentation: the well-established DeepWaterMapV2 and WatNet models and the adapted WaterSegDiff model, which is based on a combination of diffusion and transformation mechanisms specifically conditioned for lake segmentation. In addition, the Normalized Difference Water Index (NDWI) with Otsu thresholding is used for comparison purposes. To capture lakes across these regions, a new dataset was created with Landsat-8 multispectral imagery (bands 2–7) from 2013 to 2023. Quantitative and qualitative analyses were performed using metrics such as Mean Intersection over Union (MIoU), Pixel Accuracy (PA), and F1 Score. The results achieved indicate equivalent performance of DeepWaterMapV2 and WatNet encoder–decoder architectures, achieving adequate lake segmentation despite the challenging geographical and atmospheric conditions inherent in high-mountain environments. In the qualitative analysis, the behavior of the WaterSegDiff model was considered promising for the proposed application. Considering that WatNet is less computationally complex, with 3.4 million parameters, this architecture becomes the most pertinent to implement. Additionally, a detailed temporal analysis of Lake Singrenacocha in the Vilcanota Mountains was conducted, pointing out the more significant behavior of the WatNet model.