J. Francisco Vargas-Bonilla

• MSc;PhD.
• University of Antioquia

Artificial lighting was an engine of economic progress since its development allowed to extend human activities at night and to spaces where natural light did not reach. Thenceforth, artificial electric lighting has constantly evolved, in principle oriented toward improving energy efficiency, and recently giving more importance to improving color r...

Background and objectives: Parkinson's disease is a neurological disorder that affects the motor system producing lack of coordination, resting tremor, and rigidity. Impairments in handwriting are among the main symptoms of the disease. Handwriting analysis can help in supporting the diagnosis and in monitoring the progress of the disease. This pap...

Virtual education has become one of the tools most widely used by students at all educational levels, not just because of its convenience and flexibility, but also because it can expand educational coverage. All these benefits also bring along multiple issues in terms of security and reliability in the evaluation the of student’s knowledge because...

Monitoring mosquito populations is essential to designing and implementing control strategies. Recent strategies based on releasing biologically modified mosquitoes have increased the need to effectively monitor mosquito abundance. Unfortunately, existing surveillance traps are of limited value due to their high cost and low capture rates. Here, we...

Monitoring mosquito populations is essential to designing and implementing control strategies. Recent strategies based on releasing biologically modified mosquitoes have increased the need to effectively monitor mosquito abundance. Unfortunately, existing surveillance traps are of limited value due to their high cost and low capture rates. Here, we...

The embedded systems continue to display as solutions of smart surveillance systems. Background subtraction using Gaussian Mixture Model (GMM) is often portrayed as a common step for video processing. This work discusses the implementation of an embedded vision system on system-on-a-chip (SoC) device that integrates both a processor and an FPGA (Fi...

Optically pumped magnetometers (OPMs) have reached sensitivity levels that make them viable portable alternatives to traditional superconducting technology for mag-netoencephalography (MEG). OPMs do not require cryogenic cooling and can therefore be placed directly on the scalp surface. Unlike cryogenic systems, based on a well-characterised fixed...

In this paper we evaluate the suitability of handwriting patterns as potential biomarkers to model Parkinson’s disease (PD). Although the study of PD is attracting the interest of many researchers around the world, databases to evaluate handwriting patterns are scarce and knowledge about patterns associated to PD is limited and biased to the existi...

In this paper we evaluate the suitability of handwriting patterns as potential biomarkers to model Parkinson disease (PD). Although the study of PD is attracting the interest of many researchers around the world, databases to evaluate handwriting patterns are scarce and knowledge about patterns associated to PD is limited and biased to the existing...

Background and objectives: Parkinson's disease is a neurological disorder that affects the motor system producing lack of coordination, resting tremor, and rigidity. Impairments in handwriting are among the main symptoms of the disease. Handwriting analysis can help in supporting the diagnosis and in monitoring the progress of the disease. This pa...

In the recent past, estimating brain activity with magneto/electroencephalography (M/EEG) has been increasingly employed as a noninvasive technique for understanding the brain functions and neural dynamics. However, one of the main open problems when dealing with M/EEG data is its non-Gaussian and nonstationary structure. In this paper, we introduc...

Digital cameras are photodetector arrays that respond to particular bands of the electromagnetic spectrum, and specifically those in the visible spectrum between 380 and 780 nm are the most commonly used. The main cameras function is store the image from an aesthetic point of view, when these are used in home applications. For this reason , several...

Microalgae counting is used to measure biomass quantity. Usually, it is performed in a manual way using a Neubauer chamber and expert criterion, with the risk of a high error rate. This paper addresses the methodology for automatic identification of Scenedesmus microalgae (used in the methane production and food industry) and applies it to images c...

The consequences of a fall on an elderly person can be reduced if the accident is attended by medical personnel within the first hour. Independent elderly people often stay alone for long periods of time, being in more risk if they suffer a fall. The literature offers several approaches for detecting falls with embedded devices or smartphones using...

The consequences of a fall on an elderly person can be reduced if the accident is attended by medical personnel within the first hour. Independent elderly people use to stay alone for long periods of time, being in more risk if they suffer a fall. The literature offers several approaches for detecting falls with embedded devices or smartphones usin...

The consequences of a fall on an elderly person can be reduced if the accident is attended by medical personnel within the first hour. Independent elderly people use to stay alone for long periods of time, being in more risk if they suffer a fall. The literature offers several approaches for detecting falls with embedded devices or smartphones usin...

En la aviación, los fenómenos meteorológicos son uno de los aspectos más importantes para tener en cuenta en todas las etapas de vuelo, desde la planificación hasta el aterrizaje. El desarrollo de sistemas de predicción meteorológica aplicados a la aviación puede apoyar el proceso de toma de decisiones de los controladores de tráfico aéreo y los pi...

The consequences of a fall on an elderly person can be diminished if the accident is attended by medical personnel within the first hour. Independent elderly people use to stay alone for long periods of time, being in more risk if they suffer a fall. The literature offers several approaches for detecting falls with embedded devices or smartphones u...

NeuroSpeech is a software for modeling pathological speech signals considering different speech dimensions: phonation, articulation, prosody, and intelligibility. Although it was developed to model dysarthric speech signals from Parkinson's patients, its structure allows other computer scientists or developers to include other pathologies and/or me...

A new software for modeling pathological speech signals is presented in this paper. The software is called NeuroSpeech. This software enables the analysis of pathological speech signals considering different speech dimensions: phonation, articulation, prosody, and intelligibility. All the methods considered in the software have been validated in pr...

MEG/EEG brain imaging approaches are commonly based on linear covariance matrices that contain the prior information needed to solve the inverse problem. We expect that non-linear covariance matrices (or kernel matrices) provide more information than the widely used smoothers (Loreta, MSP) or data-based matrices (beamformers). Data-based covariance...

The use of wearable devices with accelerometers developed to detect falls and motion has been continuously growing because of their small size, low weight, energy efficiency, and low price. However, the number of sensors, their position in the body and estimation methodologies are still open issues when tested in uncontrolled conditions. In this pa...

This work describes a novel methodology to characterize voice diseases by using nonlinear dynamics, considering different complexity measures that are mainly based on the analysis of the time delay embedded space. The feature space is represented with a DHMM and a further transformation of the DHMM states to a hyperdimensional space is performed. T...

Research on fall and movement detection with wearable devices has witnessed promising growth. However, there are few publicly available datasets, all recorded with smartphones, which are insufficient for testing new proposals due to their absence of objective population, lack of performed activities, and limited information. Here, we present a data...

Microalgae counting is used to measure biomass quantity. Usually, it is performed in a manual way using a Neubauer chamber and expert criterion, with the risk of a high error rate. This paper addresses the methodology for automatic identification of Scenedesmus microalgae (used in the methane production and food industry) and applies it to images c...

Automatic detection of correct performance of movements in humans is the core of coaching and rehabilitation applications. Human movement can be studied in terms of sequential data by using different sensor technologies. This representation makes it possible to use models that use sequential data to determine if executions of a certain activity are...

Emotional processing of ex-combatants is affected by chronic exposure to violent events. For a successful reintegration into society, it is necessary to discriminate their brain responses from civilian people, as a first stage to develop treatment strategies. This paper presents a comparative analysis between a Multilayer Perceptron Neural Network...

Research on fall and movement detection with wearable devices has witnessed promising growth. However, there are few publicly available datasets, all recorded with smartphones, that prevent authors to evenly compare their new proposals. Here, we present a dataset of falls and activities of daily living (ADL) acquired with a self-developed device co...

The use of online messaging systems to exchange information has changed due to the ability to share text, video and pictures almost immediately. Also it has become an excellent alternative for transmitting data with certain reserve levels in places or where voice signals and other forms of communication are not of high quality and/or availability,...

La Enfermedad de Parkinson (EP) es la segunda condición clínica neurodegenerativa más prevalente después del Alzheimer y para el sistema de salud mundial es fundamental identifi car marcadores tempranos; sin embargo en la actualidad es un campo nuevo de estudio que necesita un mayor desarrollo. Se ha demostrado que cerca del 90 % de los pacientes c...

In this paper we propose a methodology for the automatic detection of Parkinson’s Disease (PD) by using several glottal flow measures including different time-frequency (TF) parameters and nonlinear behavior of the vocal folds. Additionally, the nonlinear behavior of the vocal tract is characterized using the residual wave. The proposed approach al...

Gaussian Mixture Model Universal Background Model (GMM-UBM) approach is used to assess the Parkinson’s disease (PD) progression per speaker. The disease progression is assessed individually per patient following a user modeling-approach. Voiced and unvoiced segments are extracted and grouped separately to train the models. Additionally, the Bhattac...

This paper presents a system for the automatic detection of hypernasal speech signals based on the combination of two different characterization approaches applied to the five spanish vowels and two selected words. The first approach is based on classical features such as pitch period perturbations, noise measures, and Mel-Frequency Cepstral Coeffi...

To assess the impact of Parkinson’s disease (PD) on spontaneous discourse, we conducted computerized analyses of brief monologues produced by 51 patients and 50 controls. We explored differences in semantic fields (via latent semantic analysis), grammatical choices (using part-of-speech tagging), and word-level repetitions (with graph embedding too...

Elderly fall detection based on accelerometers is an active research area. Nowadays authors are addressing specific problems such as failure rates and energy consumption, but in most cases their strategies do not conciliate these objectives. In this paper we propose a double threshold based methodology with two novel detection features, a product b...

EEG brain imaging has become a promising approach in Brain-computer interface applications. However, accurate reconstruction of active regions and computational burden are still open issues. In this paper, we propose to use a simplified forward model that includes the reduction of the cortical dipoles based on Brodmann areas together with state-of-...

In this paper we present a new database with speech recordings in Spanish. The database contains recordings of 54 native Spanish speakers. It is appropriate to be used in the development and testing of better Speaker Verification systems. The recording procedure, equipments and speech tasks are detailed. Experiments using the GMM-UBM speaker verifi...

Photodetectors are sensors, which respond to the electromagnetic radiation of the spectrum. Their spectral response depends on many factors of the manufacturing process, e.g. the type of diode that is used or, in some cases, the optical elements that are added to limit the response band. In this paper, we propose an experimental methodology to obta...

This paper addresses the problem of training on-line signature verification systems when the number of training samples is small, facing the real-world scenario when the number of available signatures per user is limited. The paper evaluates nine different classification strategies based on Gaussian Mixture Models (GMM), and the Universal Backgroun...

The suitability of articulation measures and speech intelligi-bility is evaluated to estimate the neurological state of patients with Parkinson's disease (PD). A set of measures recently introduced to model the articulatory capability of PD patients is considered. Additionally, the speech intelligibility in terms of the word accuracy obtained from...

Non intrusive monitoring of animals in the wild is possible using camera trapping framework, which uses cameras triggered by sensors to take a burst of images of animals in their habitat. However camera trapping framework produces a high volume of data (in the order on thousands or millions of images), which must be analyzed by a human expert. In t...

Automatic recognition of the quality of movement in human beings is a challenging task, given the difficulty both in defining the constraints that make a movement correct, and the difficulty in using noisy data to determine if these constraints were satisfied. This paper presents a method for the detection of deviations from the correct form in mov...

A new set of features based on non-linear dynamics measures obtained from the wavelet packet transform for the automatic recognition of “fear-type” emotions in speech is proposed. The experiments are carried out using three different databases with a Gaussian Mixture Model for classification. The results indicate that the proposed approach is promi...

The aim of this study is the analysis of continuous speech signals of people with Parkinson's disease (PD) considering recordings in different languages (Spanish, German, and Czech). A method for the characterization of the speech signals, based on the automatic segmentation of utterances into voiced and unvoiced frames, is addressed here. The...

The generation of brain images based on MEG/EEG data is an ill-posed inverse problem, meaning that additional prior information is required to reduce this uncertainty. Expressing this problem in a Bayesian framework allows us to generalize across a large set of well-known source localization algorithms: each with different forms of anatomical and f...

Recognition of human activities in videos has experienced considerable changes with the introduction of cost-effective technology that allows for the tracking of individual body parts. This has led to the development of numerous tele-health applications that aim to help patients in their recovery process. Most of these systems are based on techniqu...

Resumen Los SIT (Sistemas Inteligentes de Transporte inglés: Intelligent Transportation Systems-ITS) pueden definirse como un conjunto de soluciones tecnológicas de las telecomunicaciones e informáticas (telemáticas) que permiten optimizar los procesos y recursos para facilitar una permanente información, en tiempo real, para su estudio, evaluación...

Falling is a risk factor of vital importance in elderly adults, hence, the ability to detect falls automatically is necessary to minimize the risk of injury. In this work, we develop a fall detection algorithm based in inertial sensors due its scope of activity, portability, and low cost. This algorithm detects the fall across thresholds and residu...

The speech signals are non-stationary processes with changes in time and frequency. The structure of a speech signal is also affected by the presence of several paralinguistics phenomena such as emotions, pathologies, cognitive impairments, among others. Non-stationarity can be modeled using several parametric techniques. A novel approach based on...

The impact of speech compression in the automatic classification of speakers with Parkinson’s disease (PD) and healthy controls (HC) is tested. The set of codecs considered to compress the speech recordings includes G.722, G.226, GSM-EFR, AMR-WB, SILK, and Opus. A total of 100 speakers (50 with PD and 50 HC) are asked to read a text with 36 words....

Automatic classification of Parkinson’s disease (PD) speakers and healthy controls (HC) is performed considering speech recordings collected in non-controlled noise conditions. The speech tasks include six sentences and a read text. The recording is performed using an open source portable device and a commercial microphone. A speech enhancement (SE...

Three types of artificial light sources work with electricity: incandescent, fluorescent and LED. These sources require characterization processes to allow selecting the most suitable for the application, to evaluate their capacity or more recently to tune and adjust their replicability using control algorithms. Therefore, it has been necessary to...

Automatic emotion recognition considering speech signals has attracted the attention of the research community in the last years. One of the main challenges is to find suitable features to represent the affective state of the speaker. In this paper, a new set of features derived from the wavelet packet transform is proposed to classify different ne...

Automatic recognition of emotions in speech has attracted the attention of the research community in recent years. Some of the most relevant proposed applications of it are in call-centers. In these scenarios the speech is distorted by compression algorithms. The effects of such distortion on the performance of systems for automatic recognition of...

This paper presents a recognition scheme for therapeutical gestures by using data from a Kinect sensor. Experimental studies are conducted to determine whether the proposed calculation of angles relevant for the definition of therapeutic gestures yields results that can be used to determine, if the movement is being correctly executed. Calculation...

In this paper low-frequency analysis is addressed in order to explore components of continuous speech signals, trying to making evident the changes in the spectrum, which could be associated to the tremor in speech of people with Parkinson's disease. Four time-frequency (TF) techniques based on WignerVille distribution (WVD) are used for the charac...

As a methodology for automatic detection of Parkinson's disease (PD), it is proposed the estimation of the different glottal flow features considering nonlinear behavior of the vocal folds. This paper evaluates the discrimination capability of set with eight different Nonlinear Dynamic (NLD) features. The experiment presented considering the five S...

This paper evaluates the accuracy of different characterization methods for the automatic detection of multiple speech disorders. The speech impairments considered include dysphonia in people with Parkinson's disease (PD), dysphonia diagnosed in patients with different laryngeal pathologies (LP), and hypernasality in children with cleft lip and pal...

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About 1% of people older than 65 years suffer from Parkinson's disease (PD) and 90% of them develop several speech impairments, affecting phonation, articulation, prosody and fluency. Computer-aided tools for the automatic evaluation of speech can provide useful information to the medical experts to perform a more accurate and objective diagnosis a...

In this paper, we explore the information provided by a joint acoustic and modulation frequency representation, referred as modulation spectrum, for detection of people with Parkinsons disease through speech signals. The set of features includes the centroids and the energy content of different frequency bands in the modulation spectra of the recor...

Detection of emotion in humans from speech signals is a recent research field. One of the scenarios where this field has been applied is in situations where the human integrity and security are at risk. In this paper we are propossing a set of features based on the Teager energy operator, and several entropy measures obtained from the decomposition...

The estimation of the fundamental frequency (F0) in speech is a very important task that has been addressed by many researchers. F0 estimation can be used to separate two kind of frames from an utterance, those where the vocal folds vibrate (voiced sounds) and those where not (unvoiced sounds). The methods used to estimate F0 are affected by the pr...

Parkinson’s disease (PD) is a chronic neurodegenerative disorder of the nervous central system and it can affect the communication skills of the patients. There is an interest in the research community to develop computer aided tools for the analysis of the speech of people with PD for detection and monitoring. In this paper, three new acoustic mea...

La enfermedad de Parkinson (EP) es un desorden neurodegenerativo queafecta la coordinación de músculos y extremidades, incluyendo aquellosresponsables de la producción del habla, generando alteraciones en lainteligibilidad de la señal de voz. Está demostrado que el ejercicio terapéuticoconstante puede mejorar las habilidades de comunicación de los...

Monitoring animal species by means of the automatic sound recognition is nowadays a research field of high interest. One of the challenges of this area lies in the segmentation of the species vocalizations. Recordings acquired in natural habitats are contaminated with the sounds emitted by other species and different kinds of background noise. If t...

Parkinson's disease (PD) is the second most prevalent neurodegenerative disorder after Alzheimer’s, affecting about 1% of the people older than 65 and about 89% of the people with PD develop different speech disorders. Different researchers are currently working in the analysis of speech of people with PD, including the study of different dimension...

About 90% of the people with Parkinson's disease (PD) develop speech impairments such as monopitch, monoloudness, imprecise articulation, and other symptoms. There are several studies addressing the problem of the automatic detection of PD from speech signals in order to develop computer aided tools for the assessment and monitoring of the patients...

From the behaviour of the Raman emission spectrum, it is possible to obtain structural and compositional information of the material under study. Analysis of this information is made difficult due to low intensities of the signal, relative to noise in measurement process, and the signals generated by the nature of the compounds. Raman spectra are c...

El color es una característica perceptiva derivada de la luz que se refleja sobre los objetos y como tal no representa una propiedad física. Sin embargo, se han realizado avances en la construcción de modelos matemáticos que permitan definirlo con mayor claridad. Las fuentes de luz juegan un papel fundamental en la percepción de los colores y una d...

En este artículo se presenta una metodología para reducir el ruido de fondo en un sistema de detección de hipernasalidad; se utilizan algunas medidas clásicas de calidad e inteligibilidad para evaluar los algoritmos, que mejoran las señales de voz, utilizados en el sistema. La detección de hipernasalidad se realiza con un clasificador lineal y se c...

This paper addresses the problem of the automatic recognition of emotional states from speech recordings, especially those kind of emotions reflecting that the life or the human integrity are at risk. The paper compares the performance of two different systems: one being fed with speech signals recorded directly from the people (whole spectrum) and...

Parkinsons disease (PD) is a neurodegenerative disorder that affects the coordination and regulation of muscles and limbs, including those responsible of speech production, resulting alterations in voice intelligibility. It is already demonstrated that the constant speech therapy can improve the communication skills of the patients; however, it is...

Parkinson's disease (PD) is a neurodegenerative disorder that is characterized by the loss of dopaminergic neurons in the mid brain. It is demonstrated that about 90% of the people with PD also develop speech impairments, exhibiting symptoms such as monotonic speech, low pitch intensity, inappropriate pauses, imprecision in consonants and problems...

This paper presents a system for the automatic assessment of voice quality, according to the GRBAS scale, which considers different speech measures. The set of features includes the centroids and the energy content of different frequency bands in the modulation spectra of the recordings, Mel-frequency Cepstral Coefficients, Harmonics to Noise Ratio...

The color is a feature derived from perceptual light that is reflected on objects, as such, represents a physical property. However, progress has been made in building mathematical models to define it more clearly. Light sources play an important role in the perception of colors and one of the measures to characterize their effect is the Correlated...

From the emission bands in Raman spectra it is possible to obtain structural, vibration and compositional information in different materials. The analysis over Raman spectra must be made by experts who compare the measurements to different standard patterns previously known from the elements. The accuracy in such comparisons depends on the quality...

In this paper, the analysis of low-frequency zone of the speech signals from the five Spanish vowels, by means of the Teager energy operator (TEO) and the modified group delay functions (MGDF) is proposed for the automatic detection of Parkinson’s disease. According to our findings, different implementations of the TEO are suitable for tackling the...

Parkinson’s disease (PD) is a neurodegenerative disorder of the nervous central system and it affects the limbs motor control and the communication skills of the patients. The evolution of the disease can get to the point of affecting the intelligibility of the patient’s speech. The treatments of the PD are mainly focused on improving limb symptoms...

Different characterization approaches, including nonlinear dynamics (NLD), have been addressed for the automatic detection of PD; however, the obtained discrimination capability when only NLD features are considered has not been evaluated yet. This paper evaluates the discrimination capability of a set with ten different NLD features in the task of...

Autonomous systems can assist humans in the important task of safe driving. Such systems can warn people about possible risks, take actions to avoid accidents or guide the vehicle without human supervision. In railway scenarios a camera in front of the train can aid drivers with the identification of obstacles or strange objects that can pose dange...

Cleft lip and palate, due to morphological problems, allow the passage of air through the nasal cavity, introducing inappropriate nasal resonance during speech production and resulting in hypernasality speech. This paper proposes a methodology based on spectral and cepstral features, such as Modified Group Delay Functions with Mel Frequency Cepstra...

Problems in voice production can appear due to functional disorders and laryngeal pathologies. The presence of laryngeal pathologies can causes significant changes in the vibrational patterns of the vocal folds and it is demonstrated that the impact of such pathologies can be reduced through continuous speech therapy. We propose a methodology based...

Emotional states produce physiological alterations in the vocal tract introducing variability in the acoustic parameters of speech. Emotion recognition in speech can be used in human-machine interaction applications, speaker verification, analysis of neurological disorders and psychological diagnostic tools. This paper proposes the use of Mel Frequ...

Autonomous systems can assist humans in the important task of safe driving. Such systems can warn people about possible risks, take actions to avoid accidents or guide the vehicle without human supervision. Whether in cars or trains or ships the artificial vision algorithms offer an alternative for the design and implementation of autonomous drivin...

In this article, a system that allows optical recognition of characters in the Colombian national identity card is presented. The system is shaped by an image acquisition algorithm, by running drivers over Windows, working together with a methodology that does OCR by eliminating of the holographic background that is the mean trouble in this problem...