12 documents found, page 1 of 2
Robust automated cardiac arrhythmia detection in ECG beat signals
Victor Hugo C. de Albuquerque; Thiago M. Nunes; Danillo R. Pereira; Eduardo José da S. Luz; David Menotti; João P. Papa; João Manuel R. S. TavaresNowadays, millions of people are affected by heart diseases worldwide, whereas a considerable amount of them could be aided through an electrocardiogram (ECG) trace analysis, which involves the study of arrhythmia impacts on electrocardiogram patterns. In this work, we carried out the task of automatic arrhythmia detection in ECG patterns by means of supervised machine learning techniques, being the main contri...
Computational methods for pigmented skin lesion classification in images: revie...
Roberta B. Oliveira; João P. Papa; Aledir S. Pereira; João Manuel R. S. TavaresSkin cancer is considered as one of the most common types of cancer in several countries, and its incidence rate has increased in recent years. Melanoma cases have caused an increasing number of deaths worldwide, since this type of skin cancer is the most aggressive compared to other types. Computational methods have been developed to assist dermatologists in early diagnosis of skin cancer. An overview of the m...
Embedded real-time speed limit sign recognition using image processing and mach...
Samuel L. Gomes; Elizângela de S. Rebouças; Edson Cavalcanti Neto; João P. Papa; Victor H. C. Albuquerque; P. P. Rebouças FilhoThe number of traffic accidents in Brazil has reached alarming levels and is currently one of the leading causes of death in the country. With the number of vehicles on the roads increasing rapidly, these problems will tend to worsen. Consequently, huge investments in resources to increase road safety will be required. The vertical R-19 system for optical character recognition of regulatory traffic signs (maxim...
Computational methods for the image segmentation of pigmented skin lesions: a r...
Roberta B. Oliveira; Mercedes E. Filho; Zhen Ma; João P. Papa; Aledir S. Pereira; João Manuel R. S. TavaresBackground and objectives: Because skin cancer affects millions of people worldwide, computational methods for the segmentation of pigmented skin lesions in images have been developed in order to assist dermatologists in their diagnosis. This paper aims to present a review of the current methods, and outline a comparative analysis with regards to several of the fundamental steps of image processing, such as ima...
Ultrasonic sensor signals and optimum path forest classifier for the microstruc...
Victor Hugo C. de Albuquerque; Cleisson V. Barbosa; Cleiton C. Silva; Elineudo P. Moura; Pedro P. Rebouças Filho; João P. PapaSecondary phases, such as laves and carbides, are formed during the finalsolidification stages of nickel-based superalloy coatings deposited during the gas tungstenarc welding cold wire process. However, when aged at high temperatures, other phases canprecipitate in the microstructure, like the 00 and phases. This work presents an evaluationof the powerful optimum path forest (OPF) classifier configured with si...
On the training of artificial neural networks with radial basis function using ...
Gustavo H. Rosa; Kelton A. P. Costa; Leandro A. Passos Júnior; João P. Papa; Alexandre X. Falcão; João Manuel R. S. TavaresIn this paper, we show how to improve the Radial Basis Function Neural Networks effectiveness by using the Optimum-Path Forest clustering algorithm, since it computes the number of clusters on-the-fly, which can be very interesting for finding the Gaussians that cover the feature space. Some commonly used approaches for this task, such as the well known k-means, require the number of classes/clusters previous i...
Automatic microstructural characterization and classification using artificial ...
Thiago M. Nunes; Victor Hugo C. de Albuquerque; João P. Papa; Cleiton C. Silva; Paulo G. Normando; Elineudo P. Moura; João Manuel R. S. TavaresSecondary phases such as Laves and carbides are formed during the final solidification stages of nickel based superalloy coatings deposited during the gas tungsten arc welding cold wire process. However, when aged at high temperatures, other phases can precipitate in the microstructure, like the gamma '' and delta phases. This work presents a new application and evaluation of artificial intelligent techniques t...
Computer techniques towards the automatic characterization of graphite particle...
João P. Papa; Rodrigo Y. M. Nakamura; Victor Hugo C. de Albuquerque; Alexandre X. Falcão; João Manuel R. S. TavaresThe automatic characterization of particles in metallographic images has been paramount, mainly because of the importance of quantifying such microstructures in order to assess the mechanical properties of materials common used in industry. This automated characterization may avoid problems related with fatigue and possible measurement errors. In this paper, computer techniques are used and assessed towards the...
Speeding up optimum-path forest training by path-cost propagation
Adriana S. Iwashita; João P. Papa; Alexandre X. Falcão; Roberto A. Lotufo; Victor M. de Araújo; Victor H. Costa de AlbuquerqueIn this paper we present an optimization of the Optimum-Path Forest classifier training procedure, which is based on a theoretical relationship between minimum spanning forest and optimum-path forest for a specific path-cost function. Experiments on public datasets have shown that the proposed approach can obtain similar accuracy to the traditional one hut with faster data training.
Precipitates Segmentation from Scanning Electron Microscope Images through Mach...
João P. Papa; Clayton R. Pereira; Victor H.C. de Albuquerque; Cleiton C. Silva; Alexandre X. Falcão; João Manuel R. S.TavaresThe presence of precipitates in metallic materials affects its durability, resistance and mechanical properties. Hence, its automatic identification by image processing and machine learning techniques may lead to reliable and efficient assessments on the materials. In this paper, we introduce four widely used supervised pattern recognition techniques to accomplish metallic precipitates segmentation in scanning ...