Showing papers by "Oscar E. Martínez published in 2020"
TL;DR: A new approach to the edge detection problem is presented, specially designed to achieve high accuracy detection, below instrumental resolution (super resolution) in microscopy images, based in a modified version of a recently published algorithm, SUPPOSe, which performs a numerical reconstruction of an image as a superposition of virtual point sources.
Abstract: A new approach to the edge detection problem is presented which is specially designed to achieve high accuracy detection, below instrumental resolution (super resolution) in microscopy images. The method is based in a modified version of a recently published algorithm known as SUPPOSe, which performs a numerical reconstruction of an image as a superposition of virtual point sources. The method was tested in simulated and experimental optical microscopy images and compared to the standard Laplacian of Gaussian algorithm, showing huge differences when the size of the object is smaller than the lateral resolution provided by the instrument.
6 citations
TL;DR: It is shown that particles of different sizes are distinguished by the magnitude of the perturbations introduced in the signals, and their concentrations can be measured independently of dissolved components.
Abstract: A novel system suitable for simultaneous monitoring of both oil-in-water and suspended solids based on thermal lens spectroscopy and forward light scattering is presented. The technique measures the concentration of dissolved hydrocarbons and simultaneously detects single oil droplets and suspended particles separately. The device was tested with injection water samples from an on-field water treatment plant, and hydrocarbon concentrations were measured with a precision better than 5% in the range of up to 100 ppm, reaching resolutions as low as 0.03 ppm. Particle detection was tested with model samples of dyed and undyed polystyrene spheres acting as absorption and scattering centers, which simulated oil droplets and suspended solids, respectively. We show that particles of different sizes are distinguished by the magnitude of the perturbations introduced in the signals, and their concentrations can be measured independently of dissolved components.
4 citations
Journal Article•
TL;DR: A 33-year-old man with a history of febrile seizures and moderate-severe intellectual disability began, at 2 years, both focal and generalized daily atonic seizures, which caused facial trauma, and was diagnosed with celiac disease.
Abstract: A 33-year-old man with a history of febrile seizures and moderate-severe intellectual disability began, at 2 years, both focal and generalized daily atonic seizures, which caused facial trauma. Due to drug resistance, a vagus nerve stimulator was implanted, with partial response to it. During his follow-up, he was diagnosed with celiac disease. When performing a brain tomography, bilateral occipital pyriform calcifications were evidenced, establishing the diagnosis of celiac disease, epilepsy and cerebral calcifications. A gluten-free diet was indicated and pharmacological treatment continued, thus achieving a reduction in seizures.
1 citations
08 Jul 2020
TL;DR: This work presents a new objective function for the SUPPOSe algorithm that is independent of the source intensities, which will allow to replace the optimization of the intensities with an optimization step to fit the instrument response function for a blind deconvolution.
Abstract: The SUPPOSe algorithm for super-resolution image deconvolution relies in assuming that the image source distribution can be modeled as a superposition of point sources of equal intensities, achieving a fivefold improvement in the spatial resolution. A genetic algorithm is used to find the positions of the sources by optimizing an objective function that also depends on their intensities. In this work we present a new objective function for the SUPPOSe algorithm that is independent of the source intensities. We compare both methods and prove the same performance but without the necessity to fit the intensities. This will allow to replace the optimization of the intensities with an optimization step to fit the instrument response function for a blind deconvolution.
1 citations
01 Dec 2020
TL;DR: In this article, the authors mostraremos los estudios y mejoras del metodo SUPPOSe for deconvolucion con super-resolucion de imagenes de microscopia de fluorescencia.
Abstract: En el presente trabajo mostraremos los estudios y mejoras del metodo SUPPOSe para la deconvolucion con super-resolucion de imagenes de microscopia de fluorescencia. El metodo SUPPOSe se basa en asumir que la imagen objetivo se puede aproximar como una superposicion de fuentes puntuales virtuales de igual intensidad para luego optimizar las posiciones de dichas fuentes. Las mejoras que introduciremos seguiran 4 lineas conectadas: el estudio sistematico de las fuentes de error del metodo, la correccion de artificios, la validacion del metodo y su aceleracion de computo. Para el primer estudio construimos una familia de imagenes sinteticas y estudiamos los resultados de SUPPOSe en funcion de 3 fuentes de error. Por el otro lado, la correccion de los artificios debidos a fuentes cercanas al borde fue lograda modificando la funcion objetivo a minimizar. Para la validacion del metodo incorporamos una metrica que nos permitio cuantificar distancias entre soluciones de dos imagenes de microscopia adquiridas en las mismas condiciones y en las que no se conocia la estructura real subyacente (ground truth). Finalmente, aprovechando la paralelizacion del algoritmo, implementamos el mismo en una GPU y mostramos que el desempeno tiene una mejora de tiempo de hasta 80 veces respecto a su implementacion en CPU.
TL;DR: Las crisis epilepticas son inusuales como manifestacion inicial, pero aun mas infrecuente es su presentacion como status epilepticus no convulsivo de la enfermedad.
Abstract: Resumen La arteriopatia autosomica dominante cerebral con infartos subcorticales y leucoencefalopatia es una enfermedad autosomica dominante de pequenos vasos causada por mutaciones del gen NOTCH3. Tipicamente se presenta con migrana, eventos isquemicos cerebrales recurrentes y trastornos cognitivos. Las crisis epilepticas son inusuales como manifestacion inicial, pero aun mas infrecuente es su presentacion como status epilepticus no convulsivo 1 . Se presenta una serie familiar de 3 casos con esta arteriopatia, entre los cuales 2 de ellos tuvieron status epilepticus como manifestacion de la enfermedad.
TL;DR: In this article, the authors presented a computational method for super-resolution edge detection in single standard images that opens the possibility of detecting shapes of objects with features much smaller than the microscope's point spread function.
Abstract: Edge detection in images is a key problem in quantitative cell biology, nanophotonics and other areas, but the edge-detection algorithms that have been developed suffer from serious limitations in precision. This year, we presented a computational method for super-resolution edge detection in single standard images that opens the possibility of detecting shapes of objects with features much smaller than the microscope’s point spread function.