Search results for "òptica"
showing 10 items of 205 documents
Full parallax 3D display from Kinect v1 and v2
2017
We exploit the two different versions of Kinect, v1 and v2, for the calculation of microimages projected onto integral-imaging displays. Our approach is based on composing a three-dimensional (3-D) point cloud from a captured depth map and RGB information. These fused 3-D maps permit to generate an integral image after projecting the information through a virtual pinhole array. In our analysis, we take into account that each of the Kinect devices has its own inherent capacities and individualities. We illustrate our analysis with some imaging experiments, provide the distinctive differences between the two Kinect devices, and finally conclude that Kinect v2 allows the display of 3-D images …
Vitellionis mathematici ... Perì òptikês id est de natura ratione & proiectione radiorum visus luminum colorum atque formarum quam vulgo perspectiuam…
1535
Sign.: +4, a-z4, A-Z4, 2a-2z4, 3a-3d4, 3e5 Perì òptikês en grec en la port Port. a 2 tintes amb grav. - Capll. orn
Influencia del error refractivo en la presión intraocular y en el espesor corneal central en una población de 6 a 17 años
2013
La presión intraocular (PIO) es la manifestación del contenido de humor acuoso en circulación en el ojo, siendo fundamental que la producción y drenaje estén dentro de un equilibrio adecuado para mantener en un estado óptimo de funcionamiento las estructuras oculares. Se considera que, dependiendo de cada persona, hay unos valores críticos, a partir de los cuales se produce una alteración microvascular, con un sufrimiento sobre todo de los tejidos nutridos en la zona del nervio óptico. Si persiste en el tiempo ocasiona una neuropatía óptica crónica y progresiva llamada glaucoma.
Valores de normalidad en parámetros oculares en niños caucásicos españoles
2015
<p align="justify"><em>Objetivo</em>: cuantificar los parámetros biométricos oculares, las propiedades biomecánicas corneales, la configuración anatómica del nervio óptico y la capa de fibras nerviosas de la retina (CFNR) en un grupo de niños, mediante técnicas no invasivas. <em>Material y métodos</em>: se realizó un estudio transversal, descriptivo y no aleatorio en 293 niños sanos caucásicos con edades entre 6 y 17 años. <em>Resultados</em>: se encontró una correlación estadísticamente significativa entre la longitud axial (LA) y la histéresis corneal (CH) (p &lt; 0,001). También se encontró disminución de la CH con el incremento de la miopía …
Strain and temperature measurement discrimination with forward Brillouin scattering in optical fibers
2022
A novel method that enables simultaneous and discriminative measurement of strain and temperature using one single optical fiber is presented. The method is based on the properties of transverse acoustic mode resonances (TAMRs) of the optical fiber. In particular, it is based on the different sensitivity to temperature and strain that exhibit the radial modes R0,m and a family of torsional-radial modes denoted as T R 2 , m ( 1 ) . We show that the resonance frequencies of both types of resonances shift linearly with temperature and strain, but at different rates. By the combined use of the different sensitivities of the two families of TAMRs, we experimentally demonstrate discriminative mea…
Focus issue introduction: 3D image acquisition and display: technology, perception and applications.
2022
This Feature Issue of Optics Express is organized in conjunction with the 2021 Optica (OSA) conference on 3D Image Acquisition and Display: Technology, Perception and Applications which was held virtually from 19 to 23, July 2021 as part of the Imaging and Sensing Congress 2021. This Feature Issue presents 29 articles which cover the topics and scope of the 2021 3D conference. This Introduction provides a summary of these articles.
Experimental study of MMI structures in a switchable continuous-wave thulium-doped all-fiber laser
2022
Switchable multi-wavelength laser emission from a thulium-doped all-fiber laser is reported by implementing a tapered and a non-tapered multi-modal interference (MMI) filters. The MMI structure relies on a coreless optical fiber spliced in between two single-mode optical fibers. For the non-tapered case, a minimum insertion loss of 12.60 dB is achieved around the 2-μm region, from which stable generation of commutable dual-wavelength emission at 1986.34 nm and 2017.38 nm is obtained. On the other hand, the tapered MMI structure performs a minimum insertion loss of 8.74 dB at the 2-μm region, allowing a stable triple-wavelength emission at 1995.4 nm, 2013.3 nm, and 2038.3 nm. In addition, co…
Recent Advances in Forward Brillouin Scattering: Sensor Applications
2022
In-fiber opto-mechanics based on forward Brillouin scattering has received increasing attention because it enables sensing the surrounding of the optical fiber. Optical fiber transverse acoustic resonances are sensitive to both the inner properties of the optical fiber and the external medium. A particularly efficient pump and probe technique—assisted by a fiber grating—can be exploited for the development of point sensors of only a few centimeters in length. When measuring the acoustic resonances, this technique provides the narrowest reported linewidths and a signal-to-noise ratio better than 40 dB. The longitudinal and transverse acoustic velocities—normalized with the fiber radius—can b…
Narrowband Monolithic Perovskite-Perovskite Tandem Photodetectors
2022
Narrowband photodetectors (PDs) are sought after for many applications requiring selective spectral response. The most common systems combine optical bandpass filters with broadband photodiodes. This work reports a method to obtain a narrowband response in a perovskite PD by the monolithic integration of a perovskite photoconductor and a perovskite photodiode. The spectral response of the tandem PD is determined by the bandgap energy difference of the two perovskites, and exhibits a full width at half maximum below 85 nm, an external quantum efficiency up to 68% and a high specific detectivity of ≈1012 Jones in reverse bias, enabling the device to detect weak light signals. The absorption p…
Los ópticos-optometristas y la COVID-19
2020
Ante la declaración del estado de alarma en España por la extensión de la pandemia de SARS-Cov-2 y para saber, como profesionales sanitarios, cómo han vivido esta situación los ópticos-optometristas, se ha realizado una encuesta representativa del 60% del colectivo colegial sobre la disponibilidad de mantener los servicios de urgencia en los establecimientos sanitarios de óptica y de su voluntad para colaborar como voluntarios sanitarios en esta crisis.