Luís Alexandre Lopes Frazão

Dr. Luís Alexandre Lopes Frazão

Instituto Politécnico de Leiria, Leiria, Portugal
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orcid

Research Focus & Metrics

Academic Career Length

21Years (2006-Present)

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

Representative Publications

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25 September 2023 in Journal of Imaging
Verified
Journal Article
Open access
PDF file
ECEsteban Daniel Caiza Cumbajin
Esteban Daniel Caiza Cumbajin
Nuno RodriguesNuno Rodrigues
Nuno Rodrigues
Paulo Manuel Almeida CostaPaulo Manuel Almeida Costa
Paulo Manuel Almeida Costa
Rolando MiragaiaRolando Miragaia
Rolando Miragaia
Luís Alexandre Lopes FrazãoLuís Alexandre Lopes Frazão
Luís Alexandre Lopes Frazão
APAntónio Pereira
António Pereira
Surface defect detection with machine learning has become an important tool in industries and a large field of study for researchers or workers in recent years. It is necessary to have a simplified source of information that helps us to better focus on one type of surface. In this systematic review, we present a classification for surface defect detection based on convolutional neural networks (CNNs) focused on surface types. Findings: Out of 253 records identified, 59 primary studies were eligible. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we analyzed the structures of each study and the concepts related to defects and their types on surfaces. The presented review is mainly focused on finding a classification for the types of surfaces most used in industry (metal, building, ceramic, wood, and special). We delve into the specifics of each surface category, offering illustrative examples of their applications within both industrial and laboratory settings. Furthermore, we propose a new taxonomy of machine learning based on the obtained results and collected information. We summarized the studies and extracted the main characteristics such as type of surface, problem types, timeline, type of network, techniques, and datasets. Among the most relevant results of our analysis, we found that the metallic surface is the most used, as it is the one found in 62.71% of the studies, and the most prevalent problem type is classification, accounting for 49.15% of the total. Furthermore, we observe that transfer learning was employed in 83.05% of the studies, while data augmentation was utilized in 59.32%. Our findings also provide insights into the cameras most frequently employed, along with the strategies adopted to address illumination challenges present in certain articles and the approach to creating datasets for real-world applications. The main results presented in this review allow for a quick and efficient search of information for researchers and professionals interested in improving the results of their defect detection projects. Finally, we analyzed the trends that could open new fields of study for future research in the area of surface defect detection.

31 December 2023 in Sensors
Verified
Journal Article
Open access
PDF file
ECEsteban Daniel Caiza Cumbajin
Esteban Daniel Caiza Cumbajin
Nuno RodriguesNuno Rodrigues
Nuno Rodrigues
Paulo Manuel Almeida CostaPaulo Manuel Almeida Costa
Paulo Manuel Almeida Costa
Rolando MiragaiaRolando Miragaia
Rolando Miragaia
Luís Alexandre Lopes FrazãoLuís Alexandre Lopes Frazão
Luís Alexandre Lopes Frazão
APAntónio Pereira
António Pereira
Defect detection is a key element of quality control in today’s industries, and the process requires the incorporation of automated methods, including image sensors, to detect any potential defects that may occur during the manufacturing process. While there are various methods that can be used for inspecting surfaces, such as those of metal and building materials, there are only a limited number of techniques that are specifically designed to analyze specialized surfaces, such as ceramics, which can potentially reveal distinctive anomalies or characteristics that require a more precise and focused approach. This article describes a study and proposes an extended solution for defect detection on ceramic pieces within an industrial environment, utilizing a computer vision system with deep learning models. The solution includes an image acquisition process and a labeling platform to create training datasets, as well as an image preprocessing technique, to feed a machine learning algorithm based on convolutional neural networks (CNNs) capable of running in real time within a manufacturing environment. The developed solution was implemented and evaluated at a leading Portuguese company that specializes in the manufacturing of tableware and fine stoneware. The collaboration between the research team and the company resulted in the development of an automated and effective system for detecting defects in ceramic pieces, achieving an accuracy of 98.00% and an F1-Score of 97.29%.

30 September 2024 in Sensors
Verified
Journal Article
Open access
PDF file
RCRúben Carreira
Rúben Carreira
NCNuno Alexandre Ribeiro Costa
Nuno Alexandre Ribeiro Costa
JRJoão Ramos
João Ramos
Luís Alexandre Lopes FrazãoLuís Alexandre Lopes Frazão
Luís Alexandre Lopes Frazão
APAntónio Pereira
António Pereira
The rise of robotics and the Internet of Things (IoT) could potentially represent a significant shift towards a more integrated and automated future, where the physical and digital domains may merge. However, the integration of these technologies presents certain challenges, including compatibility issues with existing systems and the need for greater interoperability between different devices. It would seem that the rigidity of traditional robotic designs may inadvertently make these difficulties worse, which in turn highlights the potential benefits of modular solutions. Furthermore, the mastery of new technologies may introduce additional complexity due to the varying approaches taken by robot manufacturers. In order to address these issues, this research proposes a Robot Operating System (ROS2)-based middleware, called the “ROS2-based gateway”, which aims to simplify the integration of robots in different environments. By focusing on the payload layer and enabling external communication, this middleware has the potential to enhance modularity and interoperability, thus accelerating the integration process. It offers users the option of selecting payloads and communication methods via a shell interface, which the middleware then configures, ensuring adaptability. The solution proposed in this article, based on the gateway concept, offers users and programmers the flexibility to specify which payloads they want to activate depending on the task at hand and the high-level protocols they wish to use to interact with the activated payloads. This approach allows for the optimisation of hardware resources (only the necessary payloads are activated), as well as enabling the programmer/user to utilise high-level communication protocols (such as RESTful, Kafka, etc.) to interact with the activated payloads, rather than low-level programming.

13 November 2024
Verified
Conference Paper
Open access
CMCarla Mendes
Carla Mendes
RPRafael Pereira
Rafael Pereira
Luís Alexandre Lopes FrazãoLuís Alexandre Lopes Frazão
Luís Alexandre Lopes Frazão
José Carlos Bregieiro RibeiroJosé Carlos Bregieiro Ribeiro
José Carlos Bregieiro Ribeiro
Nuno RodriguesNuno Rodrigues
Nuno Rodrigues
APAntónio Pereira
António Pereira

31 May 2024
Verified
Book Chapter
Closed access
PDF file
RPRafael Pereira
Rafael Pereira
CMCarla Mendes
Carla Mendes
NCNuno Alexandre Ribeiro Costa
Nuno Alexandre Ribeiro Costa
Luís Alexandre Lopes FrazãoLuís Alexandre Lopes Frazão
Luís Alexandre Lopes Frazão
Antonio Fernández-CaballeroAntonio Fernández-Caballero
Antonio Fernández-Caballero
APAntónio Pereira
António Pereira

1 June 2019
Verified
Conference Paper
Closed access
JFJessica Ferreira
Jessica Ferreira
Mário AntunesMário Antunes
Mário Antunes
MZMykyta Zhygulskyy
Mykyta Zhygulskyy
Luís Alexandre Lopes FrazãoLuís Alexandre Lopes Frazão
Luís Alexandre Lopes Frazão