2014 XIX Symposium on Image, Signal Processing and Artificial Vision, 2014
This project deals with the implementation of an algorithm for frequency band displacement for th... more This project deals with the implementation of an algorithm for frequency band displacement for the optimization of acoustic boxes. This is particularly relevant in the Car-audio industry and similar applications, when limitations of volume and space are present. The work gives an alternative solution to the problem of huge acoustic boxes sizes for the reproduction of low frequencies, using DSP, optimizing small boxes with midrange loudspeaker, without losing the information in the low frequency region. In this paper, information about loudspeaker design and performance is held, as well as the development of an algorithm that analyzes the input signal through the FFT, in order to adapt the fundamental frequency of the input signal to a basic home system or car audio. Analyzing the results of the transfer function it can be observed how the input signal adapts, reaching the optimization of the frequency response of the sound box above the natural frequency of the loudspeaker.
Relaxation possibilities of the human brain mechanisms are correlated to the synchronization proc... more Relaxation possibilities of the human brain mechanisms are correlated to the synchronization processes between a particular sound stimulus and the brain patterns. Research about the signal ranges, frequency range, frequency inter-signal separation, intensity, or other complex models in signal synthesis, as for example, the binaural pulse generation have been widely studied. The present paper summarizes the results about the possibilities for obtaining relaxation through binaural sound playback. Here, these relaxation states are induced for therapeutic purposes. Some tests and experiment validation are performed with Biofeedback technology.
ACM Transactions on Management Information Systems
Lowering pollution levels is one of the main principles of Sustainable Development goals dictated... more Lowering pollution levels is one of the main principles of Sustainable Development goals dictated by the United Nations. Consequently, developments on noise monitoring contribute in great manner to this purpose, since they give the opportunity to governments and institutions to maintain track on the matter. While developing a software product for this purpose, with the growth in terms of functional and non-functional requirements, elements such as infrastructure, source code and others also scale up. Consequently if there are not good practices to face the new challenges of the software product, it could become more complex to refactor, maintain and scale, causing a decrease on delivery rate and the quality of the product. DevOps is an emerging concept but still hazy, which involves a set of practices that helps organizations to speed up delivery time, improve software quality and collaboration between teams. The aim of this paper is to document the implementation of some DevOps pra...
2019 XXII Symposium on Image, Signal Processing and Artificial Vision (STSIVA)
Even though there exist lot of inclusive aids on the market, a joint research between Universidad... more Even though there exist lot of inclusive aids on the market, a joint research between Universidad El Bosque and Universidad de San Buenaventura have shown that visually impaired people still face several problems while attempting to access into the public transport system. Thus, with the insight gathered during this research, the Acoustic Research Group – University of San Buenaventura has designed an android mobile application called TransmiGuía. It works with geolocation, voice recognition and help visually impaired people to navigate through the public transport system.
This project consists on the creation of a plugin on the Ableton Live platform with the aim of pr... more This project consists on the creation of a plugin on the Ableton Live platform with the aim of providing visually the audio mixing process in real-time. The software programming is developed on Max for Live – a program to establish the link between Max Msp and Ableton Live. The plugin is assigned for each channel, with the aim of visualizing the correspondent sound to a “sphere” object on a 3D window and there to observe the variations in real time of loudness, panning and frequency analysis, based on the David Gibson ́s interpretation, on his book “The Art of Mixing”.
espanolEl objetivo del presente trabajo es hacer una introduccion a la teoria basica utilizada pa... more espanolEl objetivo del presente trabajo es hacer una introduccion a la teoria basica utilizada para extraer informacion y como hacer un procesamiento de senales optimo para sistemas SoNAR activos o pasivos. En especial, se revisa como se catalogan los problemas tipicos que se tratan en sistemas tipo sonar. Se revisa la teoria estadistica que se usa en el procesamiento de senal acustica y se estudia el comportamiento de las curvas caracteristicas de operacion cuando se varia la varianza de las distribuciones de probabilidad de ruido y de senal en presencia del ruido. Por ultimo, se revisa la teoria de fondo de los problemas inversos y el procesamiento de campo ajustado para aplicarlo en un futuro a un sistema de visualizacion acuatica en condiciones de poca visibilidad. EnglishThe present work introduces the reader to the basic theory used to optimally extract and process information in passive and active sonar systems. In particular, the typical problems addressed when implementing ...
The present paper deals with the subjective evaluation of audio coding technologies using the “Si... more The present paper deals with the subjective evaluation of audio coding technologies using the “Similarity Rating” psychometric method. Compressed audio excerpts are presented to a group of experienced listeners by pairs of stimuli. Each pair represents a different type of distortion, with compression included. These types of distortion correspond to three psychoacoustic attributes, sharpness, roughness, and fluctuation strength. Listener’s task is to evaluate the degree of similarity between the pairs. The final output is the localization of each measured codec in this psychoacoustic space. Multidimensional scaling is the statistic technique, belonging to Multivariate Statistical methods, which allows processing the results obtained from this method.
El presente articulo describe las herramientas de adquisicion de senales biomedicas y la descripc... more El presente articulo describe las herramientas de adquisicion de senales biomedicas y la descripcion del proceso de transmision y recepcion de esas senales por via-celular para el monitoreo desde una aplicacion Java.
This paper focuses on auditory sensory substitution for providing visually impaired users with su... more This paper focuses on auditory sensory substitution for providing visually impaired users with suitable information in both static scene recognition and dynamic obstacle avoidance. We introduce three different sonification models together with three temporal presentation schemes, i.e. ways of temporally organizing the sonic events in order to provide suitable information. Following an overview of the motivation and challenges behind each of the solutions, we describe their implementation and an evaluation of their relative strengths and weaknesses based on a set of experiments conducted in a virtual environment.
El presente articulo trata de la evaluacion subjetiva de sistemas de codificacion de audio. De ac... more El presente articulo trata de la evaluacion subjetiva de sistemas de codificacion de audio. De acuerdo con estos resultados se encuentra que, dependiendo del tipo de la senal y dependiendo del tipo de senal y del algoritmo del sistema de codificacion de audio, diferentes tipos de errores audibles se hacen presentes. Estos errores son llamados errores de codificacion, sin embargo, mientras pueden ser perceptibles tres clases de artefactos, el autor propone que en el dominio de codificacion hay una clase comun para la aparicion de artefactos: el rastreo no eficiente de senales transientes estocasticas. Para este proposito el estado del arte de los sistemas de audio codificacion usan un gran rango de tecnicas de procesamiento de senal, para lo cual la aplicacion de la transformada de Wavelet esta descrita.
Uno de los retos que la Ingenieria afronta en la actualidad, es la posibilidad de aportar solucio... more Uno de los retos que la Ingenieria afronta en la actualidad, es la posibilidad de aportar soluciones a los problemas enmarcados por las organizaciones mundiales. Dentro de estos, podemos mencionar, el Desarrollo sostenible y sustentable, la erradicacion de la pobreza y las ayudas tecnologicas a las personas discapacitadas.
En el presente articulo, calculamos la Potencia Espectral de Barks de una forma correcta y precis... more En el presente articulo, calculamos la Potencia Espectral de Barks de una forma correcta y precisa. El presente trabajo calcula la Potencia Espectral de Barks con un error pequeno, el cual es producido cuando se calcula la Transformada Discreta de Fourier (DFT). Los investigadores tienden a olvidar las suposiciones y condiciones que son inherentes al calculo. Una corta introduccion sobre las Bandas Criticas y la Escala Bark son presentadas.
El objetivo del presente trabajo es describir los principios de compresion de senales y principio... more El objetivo del presente trabajo es describir los principios de compresion de senales y principios psicoacusticos para proveer las bases de tecnicas digitales usadas en estos campos. La compresion de senales de audio reduce la informacion de datos para almacenar y/o transmitir una senal de audio. La reduccion de memoria es realizada, reduciendo informacion redundante e irrelevante contenida en la senal.
The present project is motivated by the necessity of analyzing the technique of OFDM modulation a... more The present project is motivated by the necessity of analyzing the technique of OFDM modulation and its performance, focused to the Transmission of Digital Radio. Traditionally all the radio programs are transmitted by FM, and AM modulations, and the radio should be tuned to each one of these frequencies; this used a wide range of the spectrum for a relatively short range of stations, limiting the experience of listening. In this project, a modulation system for Digital Radio Transmission is pretended, in order to combine multiple streams of audio in a relatively narrow frequency band, centered in a definite transmission frequency.
This article deals with the design of a digitally audio controller for use in general application... more This article deals with the design of a digitally audio controller for use in general applications. The goal is to create a 10-band graphic equalizer of which the signal gain or attenuation in every octave band is controllable by a smartphone /tablet application. The application provides a user interface to enhance perceptive audio quality intuitively. Making the equalizer digitally controllable by an app eliminates the necessity of manually adjusting the equalizer faders, thus the need of the presence of a musician/engineer at the location of the equalizer is removed. Preset configurations are easily activated in the equalizer hardware with only one touch within the app. Further testing and optimization efforts are required for the validation of the system.
El principio de incertidumbre de Gabor, determina que no es posible tener optima resolucion en ti... more El principio de incertidumbre de Gabor, determina que no es posible tener optima resolucion en tiempo-frecuencia, al realizar un procesamiento digital de la senal con herramientas convencionales como la FFT. Este procesado es esencial en diversos sistemas de audio, como reve rberadores digitales, filtros y tambien en sistemas de compresion. Los sistemas de compresion perceptual de audio, minimizan el volumen informatico de la senal, hasta una tasa de 1:10. Esto proporciona la posibilidad de ahorrar espacio en los sistemas de almacenamiento y economizar anchos de banda de canales de comunicacion, para transmisiones de Radio y Video. El presente proyecto implementa un compresor perceptual, con una tecnica no-convencional. Esta es basada en la Transformada Wavelet- Daubechies Tipo IV, en cascada. Los coeficientes de los filtros paso-alto y paso-bajo son obtenidos en MATLAB, y la implementacion completa es realizada en Pure Data. Esto permite su posterior implementacion en un sistema em...
The present work is an investigation about the properties of discrete linear systems with periodi... more The present work is an investigation about the properties of discrete linear systems with periodic impulse responses. It is a particular case of LTI (Linear Time Invariant) Systems with this kind of impulse responses. We first investigate the general form of the transfer function when the impulse response of the system is periodic. Secondly, we investigate the case when the periods of the input signal and the impulse response are equal. The case when when the two periods are different, is also investigated. This last particular case is simulated in MATLAB.
Revista Facultad de Ingeniería Universidad de Antioquia
A perforated panel from guadua fibres is implemented after acoustic characterization of the fibre... more A perforated panel from guadua fibres is implemented after acoustic characterization of the fibres. The acoustic characteristics of the fibre are identified and further, the acoustic behaviour of the acoustic absorption system made from guadua is analysed. It proves the suitability of natural fibres and bioresidues for systems which goal is to bring acoustic comfort to society. In this sense, the present research is aligned with the principles of Sustainable Development agreed at Rio de Janeiro, in 1992.
2014 XIX Symposium on Image, Signal Processing and Artificial Vision, 2014
This project deals with the implementation of an algorithm for frequency band displacement for th... more This project deals with the implementation of an algorithm for frequency band displacement for the optimization of acoustic boxes. This is particularly relevant in the Car-audio industry and similar applications, when limitations of volume and space are present. The work gives an alternative solution to the problem of huge acoustic boxes sizes for the reproduction of low frequencies, using DSP, optimizing small boxes with midrange loudspeaker, without losing the information in the low frequency region. In this paper, information about loudspeaker design and performance is held, as well as the development of an algorithm that analyzes the input signal through the FFT, in order to adapt the fundamental frequency of the input signal to a basic home system or car audio. Analyzing the results of the transfer function it can be observed how the input signal adapts, reaching the optimization of the frequency response of the sound box above the natural frequency of the loudspeaker.
Relaxation possibilities of the human brain mechanisms are correlated to the synchronization proc... more Relaxation possibilities of the human brain mechanisms are correlated to the synchronization processes between a particular sound stimulus and the brain patterns. Research about the signal ranges, frequency range, frequency inter-signal separation, intensity, or other complex models in signal synthesis, as for example, the binaural pulse generation have been widely studied. The present paper summarizes the results about the possibilities for obtaining relaxation through binaural sound playback. Here, these relaxation states are induced for therapeutic purposes. Some tests and experiment validation are performed with Biofeedback technology.
ACM Transactions on Management Information Systems
Lowering pollution levels is one of the main principles of Sustainable Development goals dictated... more Lowering pollution levels is one of the main principles of Sustainable Development goals dictated by the United Nations. Consequently, developments on noise monitoring contribute in great manner to this purpose, since they give the opportunity to governments and institutions to maintain track on the matter. While developing a software product for this purpose, with the growth in terms of functional and non-functional requirements, elements such as infrastructure, source code and others also scale up. Consequently if there are not good practices to face the new challenges of the software product, it could become more complex to refactor, maintain and scale, causing a decrease on delivery rate and the quality of the product. DevOps is an emerging concept but still hazy, which involves a set of practices that helps organizations to speed up delivery time, improve software quality and collaboration between teams. The aim of this paper is to document the implementation of some DevOps pra...
2019 XXII Symposium on Image, Signal Processing and Artificial Vision (STSIVA)
Even though there exist lot of inclusive aids on the market, a joint research between Universidad... more Even though there exist lot of inclusive aids on the market, a joint research between Universidad El Bosque and Universidad de San Buenaventura have shown that visually impaired people still face several problems while attempting to access into the public transport system. Thus, with the insight gathered during this research, the Acoustic Research Group – University of San Buenaventura has designed an android mobile application called TransmiGuía. It works with geolocation, voice recognition and help visually impaired people to navigate through the public transport system.
This project consists on the creation of a plugin on the Ableton Live platform with the aim of pr... more This project consists on the creation of a plugin on the Ableton Live platform with the aim of providing visually the audio mixing process in real-time. The software programming is developed on Max for Live – a program to establish the link between Max Msp and Ableton Live. The plugin is assigned for each channel, with the aim of visualizing the correspondent sound to a “sphere” object on a 3D window and there to observe the variations in real time of loudness, panning and frequency analysis, based on the David Gibson ́s interpretation, on his book “The Art of Mixing”.
espanolEl objetivo del presente trabajo es hacer una introduccion a la teoria basica utilizada pa... more espanolEl objetivo del presente trabajo es hacer una introduccion a la teoria basica utilizada para extraer informacion y como hacer un procesamiento de senales optimo para sistemas SoNAR activos o pasivos. En especial, se revisa como se catalogan los problemas tipicos que se tratan en sistemas tipo sonar. Se revisa la teoria estadistica que se usa en el procesamiento de senal acustica y se estudia el comportamiento de las curvas caracteristicas de operacion cuando se varia la varianza de las distribuciones de probabilidad de ruido y de senal en presencia del ruido. Por ultimo, se revisa la teoria de fondo de los problemas inversos y el procesamiento de campo ajustado para aplicarlo en un futuro a un sistema de visualizacion acuatica en condiciones de poca visibilidad. EnglishThe present work introduces the reader to the basic theory used to optimally extract and process information in passive and active sonar systems. In particular, the typical problems addressed when implementing ...
The present paper deals with the subjective evaluation of audio coding technologies using the “Si... more The present paper deals with the subjective evaluation of audio coding technologies using the “Similarity Rating” psychometric method. Compressed audio excerpts are presented to a group of experienced listeners by pairs of stimuli. Each pair represents a different type of distortion, with compression included. These types of distortion correspond to three psychoacoustic attributes, sharpness, roughness, and fluctuation strength. Listener’s task is to evaluate the degree of similarity between the pairs. The final output is the localization of each measured codec in this psychoacoustic space. Multidimensional scaling is the statistic technique, belonging to Multivariate Statistical methods, which allows processing the results obtained from this method.
El presente articulo describe las herramientas de adquisicion de senales biomedicas y la descripc... more El presente articulo describe las herramientas de adquisicion de senales biomedicas y la descripcion del proceso de transmision y recepcion de esas senales por via-celular para el monitoreo desde una aplicacion Java.
This paper focuses on auditory sensory substitution for providing visually impaired users with su... more This paper focuses on auditory sensory substitution for providing visually impaired users with suitable information in both static scene recognition and dynamic obstacle avoidance. We introduce three different sonification models together with three temporal presentation schemes, i.e. ways of temporally organizing the sonic events in order to provide suitable information. Following an overview of the motivation and challenges behind each of the solutions, we describe their implementation and an evaluation of their relative strengths and weaknesses based on a set of experiments conducted in a virtual environment.
El presente articulo trata de la evaluacion subjetiva de sistemas de codificacion de audio. De ac... more El presente articulo trata de la evaluacion subjetiva de sistemas de codificacion de audio. De acuerdo con estos resultados se encuentra que, dependiendo del tipo de la senal y dependiendo del tipo de senal y del algoritmo del sistema de codificacion de audio, diferentes tipos de errores audibles se hacen presentes. Estos errores son llamados errores de codificacion, sin embargo, mientras pueden ser perceptibles tres clases de artefactos, el autor propone que en el dominio de codificacion hay una clase comun para la aparicion de artefactos: el rastreo no eficiente de senales transientes estocasticas. Para este proposito el estado del arte de los sistemas de audio codificacion usan un gran rango de tecnicas de procesamiento de senal, para lo cual la aplicacion de la transformada de Wavelet esta descrita.
Uno de los retos que la Ingenieria afronta en la actualidad, es la posibilidad de aportar solucio... more Uno de los retos que la Ingenieria afronta en la actualidad, es la posibilidad de aportar soluciones a los problemas enmarcados por las organizaciones mundiales. Dentro de estos, podemos mencionar, el Desarrollo sostenible y sustentable, la erradicacion de la pobreza y las ayudas tecnologicas a las personas discapacitadas.
En el presente articulo, calculamos la Potencia Espectral de Barks de una forma correcta y precis... more En el presente articulo, calculamos la Potencia Espectral de Barks de una forma correcta y precisa. El presente trabajo calcula la Potencia Espectral de Barks con un error pequeno, el cual es producido cuando se calcula la Transformada Discreta de Fourier (DFT). Los investigadores tienden a olvidar las suposiciones y condiciones que son inherentes al calculo. Una corta introduccion sobre las Bandas Criticas y la Escala Bark son presentadas.
El objetivo del presente trabajo es describir los principios de compresion de senales y principio... more El objetivo del presente trabajo es describir los principios de compresion de senales y principios psicoacusticos para proveer las bases de tecnicas digitales usadas en estos campos. La compresion de senales de audio reduce la informacion de datos para almacenar y/o transmitir una senal de audio. La reduccion de memoria es realizada, reduciendo informacion redundante e irrelevante contenida en la senal.
The present project is motivated by the necessity of analyzing the technique of OFDM modulation a... more The present project is motivated by the necessity of analyzing the technique of OFDM modulation and its performance, focused to the Transmission of Digital Radio. Traditionally all the radio programs are transmitted by FM, and AM modulations, and the radio should be tuned to each one of these frequencies; this used a wide range of the spectrum for a relatively short range of stations, limiting the experience of listening. In this project, a modulation system for Digital Radio Transmission is pretended, in order to combine multiple streams of audio in a relatively narrow frequency band, centered in a definite transmission frequency.
This article deals with the design of a digitally audio controller for use in general application... more This article deals with the design of a digitally audio controller for use in general applications. The goal is to create a 10-band graphic equalizer of which the signal gain or attenuation in every octave band is controllable by a smartphone /tablet application. The application provides a user interface to enhance perceptive audio quality intuitively. Making the equalizer digitally controllable by an app eliminates the necessity of manually adjusting the equalizer faders, thus the need of the presence of a musician/engineer at the location of the equalizer is removed. Preset configurations are easily activated in the equalizer hardware with only one touch within the app. Further testing and optimization efforts are required for the validation of the system.
El principio de incertidumbre de Gabor, determina que no es posible tener optima resolucion en ti... more El principio de incertidumbre de Gabor, determina que no es posible tener optima resolucion en tiempo-frecuencia, al realizar un procesamiento digital de la senal con herramientas convencionales como la FFT. Este procesado es esencial en diversos sistemas de audio, como reve rberadores digitales, filtros y tambien en sistemas de compresion. Los sistemas de compresion perceptual de audio, minimizan el volumen informatico de la senal, hasta una tasa de 1:10. Esto proporciona la posibilidad de ahorrar espacio en los sistemas de almacenamiento y economizar anchos de banda de canales de comunicacion, para transmisiones de Radio y Video. El presente proyecto implementa un compresor perceptual, con una tecnica no-convencional. Esta es basada en la Transformada Wavelet- Daubechies Tipo IV, en cascada. Los coeficientes de los filtros paso-alto y paso-bajo son obtenidos en MATLAB, y la implementacion completa es realizada en Pure Data. Esto permite su posterior implementacion en un sistema em...
The present work is an investigation about the properties of discrete linear systems with periodi... more The present work is an investigation about the properties of discrete linear systems with periodic impulse responses. It is a particular case of LTI (Linear Time Invariant) Systems with this kind of impulse responses. We first investigate the general form of the transfer function when the impulse response of the system is periodic. Secondly, we investigate the case when the periods of the input signal and the impulse response are equal. The case when when the two periods are different, is also investigated. This last particular case is simulated in MATLAB.
Revista Facultad de Ingeniería Universidad de Antioquia
A perforated panel from guadua fibres is implemented after acoustic characterization of the fibre... more A perforated panel from guadua fibres is implemented after acoustic characterization of the fibres. The acoustic characteristics of the fibre are identified and further, the acoustic behaviour of the acoustic absorption system made from guadua is analysed. It proves the suitability of natural fibres and bioresidues for systems which goal is to bring acoustic comfort to society. In this sense, the present research is aligned with the principles of Sustainable Development agreed at Rio de Janeiro, in 1992.
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Papers by Marcelo Herrera