CARLOS R. VAZQUEZ SEISDEDOS - Academia.edu (original) (raw)

Papers by CARLOS R. VAZQUEZ SEISDEDOS

Revista Cubana de Ciencias Informáticas, Mar 1, 2020

Cardiovascular diseases are the leading cause of death worldwide, accounting for 17.3 million dea... more Cardiovascular diseases are the leading cause of death worldwide, accounting for 17.3 million deaths per year. The electrocardiogram (ECG) is a non-invasive technique widely used for the detection of cardiac diseases. To increase diagnostic sensitivity, ECG is acquired during exercise stress tests or in an ambulatory way. Under these acquisition conditions, the ECG is strongly affected by some types of noise, mainly by baseline wander (BLW). In this work were implemented nine methods widely used for the elimination of BLW, which are: interpolation using cubic splines, FIR filter, IIR filter, least mean square adaptive filtering, moving-average filter, independent component analysis, interpolation and successive subtraction of median values in RR interval, empirical mode decomposition, and wavelet filtering. For the quantitative evaluation, the following similarity metrics were used: absolute maximum distance, the sum of squares of distances and percentage root-mean-square difference. Several experiments were performed using synthetic ECG signals generated by ECGSYM software, real ECG signals from QT Database, artificial BLW generated by the software and real BLW from the Noise Stress Test Database. The best results were obtained by the method based on FIR highpass filter with a cutoff frequency of 0.67 Hz.

IFMBE proceedings, 2013

Saccadic eye movements provide important information about the nervous system at several levels. ... more Saccadic eye movements provide important information about the nervous system at several levels. Latency, amplitude, duration, velocity and deviation are variables of saccades which are investigated ordinarily. The saccades onsets and ends are localized, typically, using threshold approaches based on the differentiated signal and on the signal itself. This paper present a new algorithm to estimate the onsets and ends of saccades, based on the calculation of the area of a triangle. The performance of this algorithm (in presence of noise) with two based on threshold approaches is compared. The results demonstrate that the proposed algorithm outperforms with the other two in terms of accuracy and robustness to noise on the saccadic electroculographic signal, and it presents the advantage that it doesn’t depend on the threshold.

IFMBE proceedings, 2013

This paper presents a new tool for the analysis of saccadic ocular movements from electroculograp... more This paper presents a new tool for the analysis of saccadic ocular movements from electroculographic signals. This graphic tool based in the automatic detection of the saccades it was designed with the Delphi 7.0. This tool allows, in a comfortable and efficient way: to add, to eliminate, to move the onset and offset points of saccades and to calculate the parameters for the diagnosis (latency, saccadic velocity and deviation). The obtained results allowed diminishing the errors in the diagnosis, taking into account the highly tedious way of the tool that motivated this work. Results can be analyzed graphically or numerically and also can be saved for further processing. The EOG signals in two different formats can be read and many tests can be loaded at the same time for comparison purposes. Also a detailed analysis of each calculated parameter is presented to understand its meaning.

Cardiovascular diseases are the leading cause of death worldwide, accounting for 17.3 million dea... more Cardiovascular diseases are the leading cause of death worldwide, accounting for 17.3 million deaths per year. The electrocardiogram (ECG) is a non-invasive technique widely used for the detection of cardiac diseases. To increase diagnostic sensitivity, ECG is acquired during exercise stress tests or in ambulatory way. Under these acquisition conditions, the ECG is strongly affected by some types of noises, mainly by baseline wander (BLW). In this work, nine methods, widely used, for the elimination of BLW were implemented, which are: interpolation using cubic splines, finite impulse response (FIR) filter, infinite impulse response (IIR) filter, least mean square adaptive filtering, moving-average filter, independent component analysis, interpolation and successive subtraction of median values in RR interval, empirical mode decomposition, and wavelet filtering. For the quantitative evaluation, the following similarity metrics were used: absolute maximum distance, the sum of squares of distances and percentage root-mean-square difference. Several experiments were performed using synthetic ECG signals generated by ECGSYM software, real ECG signals from QT Database, artificial BLW generated by software and real BLW from the Noise Stress Test Database. The best results were obtained by the method based on FIR high-pass filter with a cutoff frequency of 0.67 Hz.

Editora Conhecimento Livre eBooks, 2021

A monitorização ambulatorial do eletrocardiograma (ECG) possui três etapas: aquisição, processame... more A monitorização ambulatorial do eletrocardiograma (ECG) possui três etapas: aquisição, processamento e analise. Em cada uma, a informação extraída do sinal ECG ou de suas series temporais de intervalos podem ser afetadas por ruídos, interferências ou artefatos. A análise da variabilidade dos intervalos cardíacos estabelece regras para a seleção dos batimentos validos e para determinar os pontos fiduciais, especialmente o final da onda T. Este trabalho descreve dois problemas e suas soluções para a etapa de processamento do ECG. Inicialmente, é descrito um método para classificar batimentos válidos para a análise da variabilidade da frequência cardíaca, e logo, é apresentado outro método para a estimação robusta do final da onda T, baseado no cálculo de áreas de trapézios. A validação de ambos os métodos apresentou um excelente desempenho comparado com outros métodos.

MEDISAN, Jan 6, 2020

verificar que los movimientos oculares del centro de la pupila siguen fielmente a dichos patrones... more verificar que los movimientos oculares del centro de la pupila siguen fielmente a dichos patrones. Palabras clave: videoculografía; movimientos oculares; iluminación infrarroja; procesamiento de imágenes oculares.

Biomedical Signal Processing and Control, Sep 1, 2021

According to the World Health Organization, around 36% of the annual deaths are associated with c... more According to the World Health Organization, around 36% of the annual deaths are associated with cardiovascular diseases and 90% of heart attacks are preventable. Electrocardiogram signal analysis in ambulatory electrocardiography, during an exercise stress test, and in resting conditions allows cardiovascular disease diagnosis. However, during the acquisition, there is a variety of noises that may damage the signal quality thereby compromising their diagnostic potential. The baseline wander is one of the most undesirable noises. In this work, we propose a novel algorithm for BLW noise filtering using deep learning techniques. The model performance was validated using the QT Database and the MIT-BIH Noise Stress Test Database from Physionet. In addition, several comparative experiments were performed against state-of-the-art methods using traditional filtering procedures as well as deep learning techniques. The proposed approach yields the best results on four similarity metrics: the sum of squared distance, maximum absolute square, percentage of root distance, and cosine similarity with 4.29 ± 6.35 au, 0.34 ± 0.25 au, 45.35 ± 29.69 au and, 91.46 ± 8.61 au, respectively. The source code of this work, containing our method and related implementations, is freely available on Github. Keywords ECG • Baseline wander • deep learning • noise filtering * Thanks to Liset Vazquez Romaguera for fruitful discussions and document review.

arXiv (Cornell University), Jun 19, 2020

In the last decade, the development of technologies and tools for eye tracking has been a constan... more In the last decade, the development of technologies and tools for eye tracking has been a constantly growing area. Detecting the center of the pupil, using image processing techniques, has been an essential step in this process. A large number of techniques have been proposed for pupil center detection using both traditional image processing and machine learning-based methods. Despite the large number of methods proposed, no comparative work on their performance was found, using the same images and performance metrics. In this work, we aim at comparing four of the most frequently cited traditional methods for pupil center detection in terms of accuracy, robustness, and computational cost. These methods are based on the circular Hough transform, ellipse fitting, Daugman's integro-differential operator and radial symmetry transform. The comparative analysis was performed with 800 infrared images from the CASIA-IrisV3 and CASIA-IrisV4 databases containing various types of disturbances. The best performance was obtained by the method based on the radial symmetry transform with an accuracy and average robustness higher than 94%. The shortest processing time, obtained with the ellipse fitting method, was 0.06 s.

Zenodo (CERN European Organization for Nuclear Research), May 9, 2022

Zenodo (CERN European Organization for Nuclear Research), May 30, 2022

ARTÍCULO ORIGINAL Herramienta de código abierto para la anotación de imágenes oculares Open-sourc... more ARTÍCULO ORIGINAL Herramienta de código abierto para la anotación de imágenes oculares Open-source tool for eye image annotation Ferramenta de anotação de imagem de olho de código aberto

Electronics, Jan 19, 2022

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Revista Ingeniería Electrónica, Automática y Comunicaciones ISSN: 1815-5928, Jun 22, 2020

DOAJ (DOAJ: Directory of Open Access Journals), Jun 1, 2020

verificar que los movimientos oculares del centro de la pupila siguen fielmente a dichos patrones... more verificar que los movimientos oculares del centro de la pupila siguen fielmente a dichos patrones. Palabras clave: videoculografía; movimientos oculares; iluminación infrarroja; procesamiento de imágenes oculares.

IFMBE proceedings, 2013

A method to determine the position and length of the heart sound S1 is presented. First, the enve... more A method to determine the position and length of the heart sound S1 is presented. First, the envelope of PCG is determined by calculating the mean Shannon energy of PCG signal. Then, the envelope is compared with a Gaussian template. When they match, the position of the heart sound is taken as the position of maximal of the template and the length of the sound is determined from the parameter σ of the template. The accuracy and noise robustness of the method was evaluated using quasi-artificial PCG signals and real PCG records form a group of healthy volunteers. The results were good in comparison with other methods reported in literature.

arXiv (Cornell University), Jul 30, 2018

Cardiovascular diseases are the leading cause of death worldwide, accounting for 17.3 million dea... more Cardiovascular diseases are the leading cause of death worldwide, accounting for 17.3 million deaths per year. The electrocardiogram (ECG) is a non-invasive technique widely used for the detection of cardiac diseases. To increase diagnostic sensitivity, ECG is acquired during exercise stress tests or in an ambulatory way. Under these acquisition conditions, the ECG is strongly affected by some types of noise, mainly by baseline wander (BLW). In this work were implemented nine methods widely used for the elimination of BLW, which are: interpolation using cubic splines, FIR filter, IIR filter, least mean square adaptive filtering, moving-average filter, independent component analysis, interpolation and successive subtraction of median values in RR interval, empirical mode decomposition, and wavelet filtering. For the quantitative evaluation, the following similarity metrics were used: absolute maximum distance, the sum of squares of distances and percentage root-mean-square difference. Several experiments were performed using synthetic ECG signals generated by ECGSYM software, real ECG signals from QT Database, artificial BLW generated by the software and real BLW from the Noise Stress Test Database. The best results were obtained by the method based on FIR highpass filter with a cutoff frequency of 0.67 Hz.

Revista Ingeniería Electrónica, Automática y Comunicaciones ISSN: 1815-5928, Aug 27, 2016

En este trabajo se describe el diseño e implementación de un dispositivo móvil para la adquisició... more En este trabajo se describe el diseño e implementación de un dispositivo móvil para la adquisición, transmisión y visualización de la posición de un vehículo hacia un terminal remoto, compuesto por una computadora y un punto de acceso inalámbrico. El dispositivo contiene un módulo receptor de GPS PARALLAX, un conversor serie-Ethernet LANTRONIX, un visualizador de cristal líquido (LCD) y un punto de acceso inalámbrico TPLINK, todos gobernados por un microcontrolador PIC 16F870. Las pruebas experimentales del prototipo realizadas en un vehículo dentro y fuera del

Springer eBooks, 2013

Applying heart rate variability (HRV) analysis on ambulatory ECG monitoring is a very useful deci... more Applying heart rate variability (HRV) analysis on ambulatory ECG monitoring is a very useful decision support tool for cardiovascular diagnosis. The presence of non-valid beats (artefacts) on the RR interval time-series affects the diagnosis accuracy using this technique. Despite the importance of artefacts recognition prior to exclusion, no paper was found characterizing quantitatively the performance of, on the one hand, the extracted features and, on the other hand, the clustering methods on artefacts recognition for HRV analysis. In this paper we evaluate the performance of several combinations of three feature extraction methods and four clustering methods (based on machine learning techniques) for the artefacts beats recognition on the ECG signal. The trade-off between performance indexes suggests the use of a non-linear principal component analysis as feature extraction method and a multilayer perceptron (MLP) as clustering method, with sensitivity, specificity and positive-predictive-value (PPV) equal to respectively 95 %, 95.9 % and 98 %.

Zenodo (CERN European Organization for Nuclear Research), May 30, 2022

ARTÍCULO ORIGINAL Corrección del efecto de desplazamiento angular horizontal de la cabeza en prue... more ARTÍCULO ORIGINAL Corrección del efecto de desplazamiento angular horizontal de la cabeza en pruebas de estimulación visual en MATLAB Correction of horizontal and angular head displacement effects by MATLAB visual stimulation tests Correção do efeito do deslocamento angular horizontal da cabeça em testes de estimulação visual no MATLAB

Computación y Sistemas, 2021

In the last decade, the development of technologies and tools for eye tracking has been a constan... more In the last decade, the development of technologies and tools for eye tracking has been a constantly growing area. Detecting the center of the pupil, using image processing techniques, has been an essential step in this process. A large number of techniques have been proposed for pupil center detection using both traditional image processing and machine learning-based methods. Despite the large number of methods proposed, no comparative work on their performance was found, using the same images and performance metrics. In this work, we aim at comparing four of the most frequently cited traditional methods for pupil center detection in terms of accuracy, robustness, and computational cost. These methods are based on the circular Hough transform, ellipse fitting, Daugman's integro-differential operator and radial symmetry transform. The comparative analysis was performed with 800 infrared images from the CASIA-IrisV3 and CASIA-IrisV4 databases containing various types of disturbances. The best performance was obtained by the method based on the radial symmetry transform with an accuracy and average robustness higher than 94%. The shortest processing time, obtained with the ellipse fitting method, was 0.06 s.

ITEGAM- Journal of Engineering and Technology for Industrial Applications (ITEGAM-JETIA), 2015

The Electrocardiogram (ECG) ambulatory monitoring has three stages: acquisition, processing and a... more The Electrocardiogram (ECG) ambulatory monitoring has three stages: acquisition, processing and analysis, in each one, the information on ECG signal itself or the time series extracted from it are affected by noises, interferences and artifacts. T he analysis of the duration and variability of heart intervals establishes rules for the selection of valid beats and to determine with accuracy the fiducially points, especially the T wave end. This paper describes two problems and their solutions involved in the processing stage. First, a method is described to identify the valid beats for heart rate variability analysis, and then another one is presented for the determination of T wave end point, based on the calculation of trapezes areas. The validation of both methods exhibits excellent performance indexes in comparison with other approaches.

Revista Cubana de Ciencias Informáticas, Mar 1, 2020

Cardiovascular diseases are the leading cause of death worldwide, accounting for 17.3 million dea... more Cardiovascular diseases are the leading cause of death worldwide, accounting for 17.3 million deaths per year. The electrocardiogram (ECG) is a non-invasive technique widely used for the detection of cardiac diseases. To increase diagnostic sensitivity, ECG is acquired during exercise stress tests or in an ambulatory way. Under these acquisition conditions, the ECG is strongly affected by some types of noise, mainly by baseline wander (BLW). In this work were implemented nine methods widely used for the elimination of BLW, which are: interpolation using cubic splines, FIR filter, IIR filter, least mean square adaptive filtering, moving-average filter, independent component analysis, interpolation and successive subtraction of median values in RR interval, empirical mode decomposition, and wavelet filtering. For the quantitative evaluation, the following similarity metrics were used: absolute maximum distance, the sum of squares of distances and percentage root-mean-square difference. Several experiments were performed using synthetic ECG signals generated by ECGSYM software, real ECG signals from QT Database, artificial BLW generated by the software and real BLW from the Noise Stress Test Database. The best results were obtained by the method based on FIR highpass filter with a cutoff frequency of 0.67 Hz.

IFMBE proceedings, 2013

Saccadic eye movements provide important information about the nervous system at several levels. ... more Saccadic eye movements provide important information about the nervous system at several levels. Latency, amplitude, duration, velocity and deviation are variables of saccades which are investigated ordinarily. The saccades onsets and ends are localized, typically, using threshold approaches based on the differentiated signal and on the signal itself. This paper present a new algorithm to estimate the onsets and ends of saccades, based on the calculation of the area of a triangle. The performance of this algorithm (in presence of noise) with two based on threshold approaches is compared. The results demonstrate that the proposed algorithm outperforms with the other two in terms of accuracy and robustness to noise on the saccadic electroculographic signal, and it presents the advantage that it doesn’t depend on the threshold.

IFMBE proceedings, 2013

This paper presents a new tool for the analysis of saccadic ocular movements from electroculograp... more This paper presents a new tool for the analysis of saccadic ocular movements from electroculographic signals. This graphic tool based in the automatic detection of the saccades it was designed with the Delphi 7.0. This tool allows, in a comfortable and efficient way: to add, to eliminate, to move the onset and offset points of saccades and to calculate the parameters for the diagnosis (latency, saccadic velocity and deviation). The obtained results allowed diminishing the errors in the diagnosis, taking into account the highly tedious way of the tool that motivated this work. Results can be analyzed graphically or numerically and also can be saved for further processing. The EOG signals in two different formats can be read and many tests can be loaded at the same time for comparison purposes. Also a detailed analysis of each calculated parameter is presented to understand its meaning.

Cardiovascular diseases are the leading cause of death worldwide, accounting for 17.3 million dea... more Cardiovascular diseases are the leading cause of death worldwide, accounting for 17.3 million deaths per year. The electrocardiogram (ECG) is a non-invasive technique widely used for the detection of cardiac diseases. To increase diagnostic sensitivity, ECG is acquired during exercise stress tests or in ambulatory way. Under these acquisition conditions, the ECG is strongly affected by some types of noises, mainly by baseline wander (BLW). In this work, nine methods, widely used, for the elimination of BLW were implemented, which are: interpolation using cubic splines, finite impulse response (FIR) filter, infinite impulse response (IIR) filter, least mean square adaptive filtering, moving-average filter, independent component analysis, interpolation and successive subtraction of median values in RR interval, empirical mode decomposition, and wavelet filtering. For the quantitative evaluation, the following similarity metrics were used: absolute maximum distance, the sum of squares of distances and percentage root-mean-square difference. Several experiments were performed using synthetic ECG signals generated by ECGSYM software, real ECG signals from QT Database, artificial BLW generated by software and real BLW from the Noise Stress Test Database. The best results were obtained by the method based on FIR high-pass filter with a cutoff frequency of 0.67 Hz.

Editora Conhecimento Livre eBooks, 2021

A monitorização ambulatorial do eletrocardiograma (ECG) possui três etapas: aquisição, processame... more A monitorização ambulatorial do eletrocardiograma (ECG) possui três etapas: aquisição, processamento e analise. Em cada uma, a informação extraída do sinal ECG ou de suas series temporais de intervalos podem ser afetadas por ruídos, interferências ou artefatos. A análise da variabilidade dos intervalos cardíacos estabelece regras para a seleção dos batimentos validos e para determinar os pontos fiduciais, especialmente o final da onda T. Este trabalho descreve dois problemas e suas soluções para a etapa de processamento do ECG. Inicialmente, é descrito um método para classificar batimentos válidos para a análise da variabilidade da frequência cardíaca, e logo, é apresentado outro método para a estimação robusta do final da onda T, baseado no cálculo de áreas de trapézios. A validação de ambos os métodos apresentou um excelente desempenho comparado com outros métodos.

MEDISAN, Jan 6, 2020

verificar que los movimientos oculares del centro de la pupila siguen fielmente a dichos patrones... more verificar que los movimientos oculares del centro de la pupila siguen fielmente a dichos patrones. Palabras clave: videoculografía; movimientos oculares; iluminación infrarroja; procesamiento de imágenes oculares.

Biomedical Signal Processing and Control, Sep 1, 2021

According to the World Health Organization, around 36% of the annual deaths are associated with c... more According to the World Health Organization, around 36% of the annual deaths are associated with cardiovascular diseases and 90% of heart attacks are preventable. Electrocardiogram signal analysis in ambulatory electrocardiography, during an exercise stress test, and in resting conditions allows cardiovascular disease diagnosis. However, during the acquisition, there is a variety of noises that may damage the signal quality thereby compromising their diagnostic potential. The baseline wander is one of the most undesirable noises. In this work, we propose a novel algorithm for BLW noise filtering using deep learning techniques. The model performance was validated using the QT Database and the MIT-BIH Noise Stress Test Database from Physionet. In addition, several comparative experiments were performed against state-of-the-art methods using traditional filtering procedures as well as deep learning techniques. The proposed approach yields the best results on four similarity metrics: the sum of squared distance, maximum absolute square, percentage of root distance, and cosine similarity with 4.29 ± 6.35 au, 0.34 ± 0.25 au, 45.35 ± 29.69 au and, 91.46 ± 8.61 au, respectively. The source code of this work, containing our method and related implementations, is freely available on Github. Keywords ECG • Baseline wander • deep learning • noise filtering * Thanks to Liset Vazquez Romaguera for fruitful discussions and document review.

arXiv (Cornell University), Jun 19, 2020

In the last decade, the development of technologies and tools for eye tracking has been a constan... more In the last decade, the development of technologies and tools for eye tracking has been a constantly growing area. Detecting the center of the pupil, using image processing techniques, has been an essential step in this process. A large number of techniques have been proposed for pupil center detection using both traditional image processing and machine learning-based methods. Despite the large number of methods proposed, no comparative work on their performance was found, using the same images and performance metrics. In this work, we aim at comparing four of the most frequently cited traditional methods for pupil center detection in terms of accuracy, robustness, and computational cost. These methods are based on the circular Hough transform, ellipse fitting, Daugman's integro-differential operator and radial symmetry transform. The comparative analysis was performed with 800 infrared images from the CASIA-IrisV3 and CASIA-IrisV4 databases containing various types of disturbances. The best performance was obtained by the method based on the radial symmetry transform with an accuracy and average robustness higher than 94%. The shortest processing time, obtained with the ellipse fitting method, was 0.06 s.

Zenodo (CERN European Organization for Nuclear Research), May 9, 2022

Zenodo (CERN European Organization for Nuclear Research), May 30, 2022

ARTÍCULO ORIGINAL Herramienta de código abierto para la anotación de imágenes oculares Open-sourc... more ARTÍCULO ORIGINAL Herramienta de código abierto para la anotación de imágenes oculares Open-source tool for eye image annotation Ferramenta de anotação de imagem de olho de código aberto

Electronics, Jan 19, 2022

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Revista Ingeniería Electrónica, Automática y Comunicaciones ISSN: 1815-5928, Jun 22, 2020

DOAJ (DOAJ: Directory of Open Access Journals), Jun 1, 2020

verificar que los movimientos oculares del centro de la pupila siguen fielmente a dichos patrones... more verificar que los movimientos oculares del centro de la pupila siguen fielmente a dichos patrones. Palabras clave: videoculografía; movimientos oculares; iluminación infrarroja; procesamiento de imágenes oculares.

IFMBE proceedings, 2013

A method to determine the position and length of the heart sound S1 is presented. First, the enve... more A method to determine the position and length of the heart sound S1 is presented. First, the envelope of PCG is determined by calculating the mean Shannon energy of PCG signal. Then, the envelope is compared with a Gaussian template. When they match, the position of the heart sound is taken as the position of maximal of the template and the length of the sound is determined from the parameter σ of the template. The accuracy and noise robustness of the method was evaluated using quasi-artificial PCG signals and real PCG records form a group of healthy volunteers. The results were good in comparison with other methods reported in literature.

arXiv (Cornell University), Jul 30, 2018

Cardiovascular diseases are the leading cause of death worldwide, accounting for 17.3 million dea... more Cardiovascular diseases are the leading cause of death worldwide, accounting for 17.3 million deaths per year. The electrocardiogram (ECG) is a non-invasive technique widely used for the detection of cardiac diseases. To increase diagnostic sensitivity, ECG is acquired during exercise stress tests or in an ambulatory way. Under these acquisition conditions, the ECG is strongly affected by some types of noise, mainly by baseline wander (BLW). In this work were implemented nine methods widely used for the elimination of BLW, which are: interpolation using cubic splines, FIR filter, IIR filter, least mean square adaptive filtering, moving-average filter, independent component analysis, interpolation and successive subtraction of median values in RR interval, empirical mode decomposition, and wavelet filtering. For the quantitative evaluation, the following similarity metrics were used: absolute maximum distance, the sum of squares of distances and percentage root-mean-square difference. Several experiments were performed using synthetic ECG signals generated by ECGSYM software, real ECG signals from QT Database, artificial BLW generated by the software and real BLW from the Noise Stress Test Database. The best results were obtained by the method based on FIR highpass filter with a cutoff frequency of 0.67 Hz.

Revista Ingeniería Electrónica, Automática y Comunicaciones ISSN: 1815-5928, Aug 27, 2016

En este trabajo se describe el diseño e implementación de un dispositivo móvil para la adquisició... more En este trabajo se describe el diseño e implementación de un dispositivo móvil para la adquisición, transmisión y visualización de la posición de un vehículo hacia un terminal remoto, compuesto por una computadora y un punto de acceso inalámbrico. El dispositivo contiene un módulo receptor de GPS PARALLAX, un conversor serie-Ethernet LANTRONIX, un visualizador de cristal líquido (LCD) y un punto de acceso inalámbrico TPLINK, todos gobernados por un microcontrolador PIC 16F870. Las pruebas experimentales del prototipo realizadas en un vehículo dentro y fuera del

Springer eBooks, 2013

Applying heart rate variability (HRV) analysis on ambulatory ECG monitoring is a very useful deci... more Applying heart rate variability (HRV) analysis on ambulatory ECG monitoring is a very useful decision support tool for cardiovascular diagnosis. The presence of non-valid beats (artefacts) on the RR interval time-series affects the diagnosis accuracy using this technique. Despite the importance of artefacts recognition prior to exclusion, no paper was found characterizing quantitatively the performance of, on the one hand, the extracted features and, on the other hand, the clustering methods on artefacts recognition for HRV analysis. In this paper we evaluate the performance of several combinations of three feature extraction methods and four clustering methods (based on machine learning techniques) for the artefacts beats recognition on the ECG signal. The trade-off between performance indexes suggests the use of a non-linear principal component analysis as feature extraction method and a multilayer perceptron (MLP) as clustering method, with sensitivity, specificity and positive-predictive-value (PPV) equal to respectively 95 %, 95.9 % and 98 %.

Zenodo (CERN European Organization for Nuclear Research), May 30, 2022

ARTÍCULO ORIGINAL Corrección del efecto de desplazamiento angular horizontal de la cabeza en prue... more ARTÍCULO ORIGINAL Corrección del efecto de desplazamiento angular horizontal de la cabeza en pruebas de estimulación visual en MATLAB Correction of horizontal and angular head displacement effects by MATLAB visual stimulation tests Correção do efeito do deslocamento angular horizontal da cabeça em testes de estimulação visual no MATLAB

Computación y Sistemas, 2021

In the last decade, the development of technologies and tools for eye tracking has been a constan... more In the last decade, the development of technologies and tools for eye tracking has been a constantly growing area. Detecting the center of the pupil, using image processing techniques, has been an essential step in this process. A large number of techniques have been proposed for pupil center detection using both traditional image processing and machine learning-based methods. Despite the large number of methods proposed, no comparative work on their performance was found, using the same images and performance metrics. In this work, we aim at comparing four of the most frequently cited traditional methods for pupil center detection in terms of accuracy, robustness, and computational cost. These methods are based on the circular Hough transform, ellipse fitting, Daugman's integro-differential operator and radial symmetry transform. The comparative analysis was performed with 800 infrared images from the CASIA-IrisV3 and CASIA-IrisV4 databases containing various types of disturbances. The best performance was obtained by the method based on the radial symmetry transform with an accuracy and average robustness higher than 94%. The shortest processing time, obtained with the ellipse fitting method, was 0.06 s.

ITEGAM- Journal of Engineering and Technology for Industrial Applications (ITEGAM-JETIA), 2015

The Electrocardiogram (ECG) ambulatory monitoring has three stages: acquisition, processing and a... more The Electrocardiogram (ECG) ambulatory monitoring has three stages: acquisition, processing and analysis, in each one, the information on ECG signal itself or the time series extracted from it are affected by noises, interferences and artifacts. T he analysis of the duration and variability of heart intervals establishes rules for the selection of valid beats and to determine with accuracy the fiducially points, especially the T wave end. This paper describes two problems and their solutions involved in the processing stage. First, a method is described to identify the valid beats for heart rate variability analysis, and then another one is presented for the determination of T wave end point, based on the calculation of trapezes areas. The validation of both methods exhibits excellent performance indexes in comparison with other approaches.