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1.
Front Neurosci ; 15: 526257, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33994912

RESUMO

The reconstruction of electrophysiological sources within the brain is sensitive to the constructed head model, which depends on the positioning accuracy of anatomical landmarks known as fiducials. In this work, we propose an algorithm for the automatic detection of fiducial landmarks of EEG electrodes on the 3D human head model. Our proposal combines a dimensional reduction approach with a perspective projection from 3D to 2D object space; the eye and ear automatic detection in a 2D face image by two cascades of classifiers and geometric transformations to obtain 3D spatial coordinates of the landmarks and to generate the head coordinate system, This is accomplished by considering the characteristics of the scanner information. Capturing the 3D model of the head is done with Occipital Inc. ST01 structure sensor and the implementation of our algorithm was carried out on MATLAB R2018b using the Computer Vision Toolbox and the FieldTrip Toolbox. The experimental results were aimed at recursively exploring the efficacy of the facial feature detectors as a function of the projection angle; they show that robust results are obtained in terms of false acceptance rate. Our proposal is an initial step of an approach for the automatic digitization of electrode locations. The experimental results demonstrate that the proposed method detects anatomical facial landmarks automatically, accurately, and rapidly.

2.
Anal Chim Acta ; 595(1-2): 145-51, 2007 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-17605994

RESUMO

A comparative study of four enhancement algorithms traditionally used in computer vision for photometric normalization of images affected by illumination changes is presented in this paper. We experimented with the performance of these approaches to reduce the low frequency multiplicative noise that is produced as a result of a non-homogeneity illumination or a non-homogeneity developed chemical process in polyacrylamide gel electrophoresis images for the purpose of automatic classification of deoxyribo nucleic acid (DNA). The algorithms are tested on a database and their results are compared in a system for feature extraction and DNA classification.


Assuntos
Algoritmos , DNA/análise , DNA/classificação , Eletroforese em Gel de Poliacrilamida/métodos , Fotometria/métodos , Eletroforese em Gel de Poliacrilamida/tendências , Géis , Fotometria/tendências
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