Denis Salvadeo

Dr. Denis Salvadeo

orcid

Research Focus & Metrics

Academic Career Length

19Years (2008-Present)

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

Representative Publications

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25 October 2024 in Electric Power Systems Research
Verified
Journal Article
Closed access
AFAndréia B.A. Ferreira
Andréia B.A. Ferreira
JLJonatas Boas Leite
Jonatas Boas Leite
DSDenis Salvadeo
Denis Salvadeo

19 December 2022 in Sensors
Verified
Journal Article
Open access
PDF file
DPDavi Duarte de Paula
Davi Duarte de Paula
DSDenis Salvadeo
Denis Salvadeo
DADarlan M. N. Araújo
Darlan M. N. Araújo
(1) Background: The research area of video surveillance anomaly detection aims to automatically detect the moment when a video surveillance camera captures something that does not fit the normal pattern. This is a difficult task, but it is important to automate, improve, and lower the cost of the detection of crimes and other accidents. The UCF–Crime dataset is currently the most realistic crime dataset, and it contains hundreds of videos distributed in several categories; it includes a robbery category, which contains videos of people stealing material goods using violence, but this category only includes a few videos. (2) Methods: This work focuses only on the robbery category, presenting a new weakly labelled dataset that contains 486 new real–world robbery surveillance videos acquired from public sources. (3) Results: We have modified and applied three state–of–the–art video surveillance anomaly detection methods to create a benchmark for future studies. We showed that in the best scenario, taking into account only the anomaly videos in our dataset, the best method achieved an AUC of 66.35%. When all anomaly and normal videos were taken into account, the best method achieved an AUC of 88.75%. (4) Conclusion: This result shows that there is a huge research opportunity to create new methods and approaches that can improve robbery detection in video surveillance.

1 June 2008
Verified
Conference Paper
Closed access
ALAlexandre Levada
Alexandre Levada
DCDebora C. Correa
Debora C. Correa
DSDenis Salvadeo
Denis Salvadeo
JSJose H. Saito
Jose H. Saito
NMNelson D. A. Mascarenhas
Nelson D. A. Mascarenhas
This paper presents novel methodologies for face recognition: template-matching using Dynamic Time Warping (DTW) and Long-Short-Term-Memory (LSTM) neural network supervised classification. The advantage of the DTW algorithm is that it requires only one prototype (sample) for each class, that is, a single representative template is enough for classification purposes. The LSTM network is a novel recurrent network architecture that implements an appropriate gradient-based learning algorithm. It overcomes the vanishing-gradient problem. Experiments with images from the MIT-CBCL face recognition database provided good results for both approaches. For DTW, the obtained results indicate that the proposed method is robust against the presence of random noise on observations and templates, since it is capable to deal with unpredictable variations. The LSTM training achieved good performance even with small feature sets.

1 January 2016 in Journal of Electronic Imaging
Verified
Journal Article
Closed access
PDF file
DSDenis Salvadeo
Denis Salvadeo
NMNelson D. A. Mascarenhas
Nelson D. A. Mascarenhas
ALAlexandre Levada
Alexandre Levada
Currently, the state-of-the art methods for image denoising are patch-based approaches. Redundant information present in nonlocal regions (patches) of the image is considered for better image modeling, resulting in an improved quality of filtering. In this respect, nonlocal Markov random field (MRF) models are proposed by redefining the energy functions of classical MRF models to adopt a nonlocal approach. With the new energy functions, the pairwise pixel interaction is weighted according to the similarities between the patches corresponding to each pair. Also, a maximum pseudolikelihood estimation of the spatial dependency parameter (β) for these models is presented here. For evaluating this proposal, these models are used as an a priori model in a maximum a posteriori estimation to denoise additive white Gaussian noise in images. Finally, results display a notable improvement in both quantitative and qualitative terms in comparison with the local MRFs.

14 December 2024 in Foods
Verified
Journal Article
Open access
PDF file
JVJean Pierre Brik López Vargas
Jean Pierre Brik López Vargas
KAKatariny Lima de Abreu
Katariny Lima de Abreu
DPDavi Duarte de Paula
Davi Duarte de Paula
DSDenis Salvadeo
Denis Salvadeo
LSLilian Francisco Arantes de Souza
Lilian Francisco Arantes de Souza
CRCarlos Bôa-Viagem Rabello
Carlos Bôa-Viagem Rabello
The egg has natural barriers that prevent microbiological contamination and promote food safety. The use of non-destructive methods to obtain morphometric measurements of chicken eggs has the potential to replace traditional invasive techniques, offering greater efficiency and accuracy. This paper aims to demonstrate that estimates derived from non-invasive approaches, such as 3D computed tomography (CT) image analysis, can be comparable to conventional destructive methods. To achieve this goal, two widely recognized deep learning architectures, U-Net 3D and Fully Convolutional Networks (FCN) 3D, were modeled to segment and analyze 3D CT images of chicken eggs. A dataset of real CT images was created and labeled, allowing the extraction of important morphometric measurements, including height, width, shell thickness, and volume. The models achieved an accuracy of up to 98.69%, demonstrating their effectiveness compared to results from manual measurements. These findings highlight the potential of CT image analysis, combined with deep learning, as a non-invasive alternative in industrial and research settings. This approach not only minimizes the need for invasive procedures but also offers a scalable and reliable method for egg quality assessment.

1 July 2009
Verified
Conference Paper
Closed access
JPJoao P. Papa
Joao P. Papa
AFAlexandre X. Falcao
Alexandre X. Falcao
ALAlexandre Levada
Alexandre Levada
DCDebora C. Correa
Debora C. Correa
DSDenis Salvadeo
Denis Salvadeo
NMNelson D. A. Mascarenhas
Nelson D. A. Mascarenhas
This paper presents a novel, fast and accurate holistic method for face-recognition using the Optimum-Path Forest (OPF) classifier. Our objective is to improve the face recognition accuracy against traditional methods and to reduce the computational effort in face recognition tasks. During the feature extraction stage we apply principal component analysis to reduce feature vectors in several dimensionalities. Experiments using face images from three public datasets (ORL, CBCL and YALE) present good results. Comparison among two other widely used supervised classifiers, artificial neural networks based on multilayer perceptron and support vector machines, show that the proposed method drastically reduces the computational cost, achieving correct classification rates at least identical to SVM.