Examinando por Autor "Loaiza Correa, Humberto"

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Determinación semiautomática de parámetros morfológicos de la huella plantar mediante el procesamiento digital de imágenes
(Universidad Icesi, 2013-10-01) Magdalena, Ximena; Loaiza Correa, Humberto; Ferrin B., Carlos Diego
Morphological parameters of footprint plantar allow carrying out podiatric assessment. It allows studying changes and making clinical and sports decisions. However, in most of cases, these are manually obtained,and in the best case it is possible to use generic image manipulation programs; in conclusion, subjectivity and tediousness are current problems in this context. In this paper, a computer assisted proposal, to determine morphological parameters based on pedographies, is developed. To get the challenge, color based segmentation techniques, border detector based on optimal operator, and key points selection by discrete optimization, are identified. As a result, techniques show robustness against light source interference, spectral flexibility, and extendible to images of non luminous nature. In general, our approach is faster than conventional methodologies, with a rapid learning curve, allowing non specialized people make podiatric research and assessment easily
Modelo de estimación diferencial de la propagación térmica en 3D mediante diferencias finitas
(Universidad Icesi, 2012-04-01) Loaiza Correa, Humberto; Restrepo Girón, Andrés David
In this paper, a new mathematical model based on finite difference discretization of the Fourier’s 3D heat propagation model, is shown. From this one, a new technique is proposed to detect flaws in composite thin layers, under evaluation by a Pulsed Active Thermography experiment. The discrete model defined is easily adaptable to a spatial filter structure, which can be applied to the infrared sequence of images acquired from that thermography experiment, to obtain a better contrast between possible internal flaws and sound regions of material. The performance of the technique proposed is evaluated using artificial thermal sequences generated by ThermoCalc6L, software that is able to compute dynamic thermal distributions in anisotropic layered solids, simulating defects and different excitation sets. Results show that this technique offers a better contrast between defect and background thermal information, than other common technique like Differential Absolute Contrast (DAC), and it runs faster than the classic 3D thermal filtering method. Palabras clave Termografía activa; termografía pulsada; propagación térmica; contraste térmico; filtro espacial. Keywords Active thermography; pulsed thermography; thermal propagation; thermal contrast; spatial filter. 1 Fecha de recepción: Abril 13 de 2012 Fecha de aceptación: Mayo 14 de 2012 Andrés David Restrepo Girón, MSc adareg378@gmail.com Grupo de Investigación en Instrumentación Electrónica (GIE) Universidad Santiago de Cali, Colombia Humberto Loaiza Correa, PhD humberto.loaiza@correounivalle.edu.co Grupo de Investigación en Percepción y Sistemas inteligentes (PSI) Universidad del Valle, Colombia Citación: Restrepo, A. & Loaiza, H.(2012). Modelo de estimación diferencial de la propagación térmica en 3D mediante diferencias finitas. Revista S&T, 10(21), 9-26 Modelo de estimación diferencial de la propagación térmica en 3D mediante diferencias finitas A model for differential estimation of 3D thermal