Mejora de la captura y reproducción de imágenes integrales mediante la implementación de técnicas ópticas. Aplicaciones industriales

Las imágenes tridimensionales proporcionan una visión realista del mundo que nos rodea, de ahí el interés por reproducirlas de ese modo. Esto no solo es atractivo desde una perspectiva visual y recreativa, sino que aporta un gran valor al estudio en ciencias y medicina, y al análisis y detección en los procesos industriales. De entre las técnicas que hay para capturar y reproducir imágenes 3D reales, la de imagen integral es la única capaz de hacerlo con luz natural, de forma autoestereoscópica, con paralaje continuo vertical y horizontal, en tiempo real y con tecnología de consumo. Sin embargo, y aunque se han producido grandes avances en los últimos veinte años, la técnica aún presenta ciertos problemas que frenan su uso masivo. Entre ellos destacan su baja resolución lateral, la reducida profundidad de campo, un ángulo de visión muchas veces insuficiente y la aparición de imágenes fantasma más allá de ese ángulo de visión. En esta tesis revisamos los parámetros fundamentales en imagen integral y los comparamos con sus homólogos de imagen convencional. Sobre esta base, identificamos los problemas citados y presentamos dos métodos puramente ópticos para, uno, aumentar la profundidad de campo durante el proceso de captura; el otro, para evitar la aparición de imágenes fantasma durante la visualización y aumentar el rango de paralaje de las imágenes 3D

The Lightfield microscope eyepiece

Lightfield microscopy has raised growing interest in the last few years. Its ability to get three-dimensional information about the sample in a single shot makes it suitable for many applications in which time resolution is fundamental. In this paper we present a novel device, which is capable of converting any conventional microscope into a lightfield microscope. Based on the Fourier integral microscope concept, we designed the lightfield microscope eyepiece. This is coupled to the eyepiece port, to let the user exploit all the host microscope's components (objective turret, illumination systems, translation stage, etc.) and get a 3D reconstruction of the sample. After the optical design, a proof-of-concept device was built with off-the-shelf optomechanical components. Here, its optical performances are demonstrated, which show good matching with the theoretical ones. Then, the pictures of different samples taken with the lightfield eyepiece are shown, along with the corresponding reconstructions. We demonstrated the functioning of the lightfield eyepiece and lay the foundation for the development of a commercial device that works with any microscope

Fast and robust wave optics-based reconstruction protocol for Fourier lightfield microscopy

Fourier lightfield microscopy (FLMic) is a powerful technique to record 3D images of thick dynamic samples. Belonging FLMic to the general class of computational imaging techniques, its efficiency is determined by several factors, like the optical system, the calibration process, the reconstruction algorithm, or the computation architecture. In the case of FLMic the calibration and the reconstruction algorithm should be fully adapted to the singular features of the technique. To this end, and concerning the reconstruction, we discard the use of experimental PSFs, and propose the use of a synthetic one, which is calculated on the basis of paraxial optics and taking into account the equal influence of diffraction and pixelation. Using this quite simple PSF, performing the adequate calibration and finally implementing the algorithm in GPU, we demonstrate here the possibility of obtaining 3D images with good results in terms of resolution and strong improvement in terms of computation time. In summary, and aiming to accelerate the widespread of FLMic among microscopy users and researchers, we are proposing a fast protocol fully adapted to FLMic and that is very flexible and robust against any slight misalignment or against the change of any optical element

Enhanced field-of-view integral imaging display using multi-Köhler illumination

A common drawback in 3D integral imaging displays is the appearance of pseudoimages beyond the viewing angle. These pseudoimages appear when the light rays coming from each elemental image are not passing through the corresponding microlens, and a set of barriers must be used to avoid this flipping effect. We present a pure optical arrangement based on Köhler illumination to generate these barriers thus avoiding the pseudoimages. The proposed system does not use additional lenses to project the elemental images, so no optical aberrations are introduced. As an added benefit, Köhler illumination provides a higher contrast 3D display.This work was supported in part by the Plan Nacional I + D + I, under Grants DPI2012-32994 and ENE2013-48565-C2-2-P, Ministerio de Economía y Competitividad (Spain), and also by the Generalitat Valenciana (Spain) under Grant PROMETEOII/2014/072. The work of Ángel Tolosa was supported by the Generalitat Valenciana under IVACE Grant PROMECE 2014

Examining the utility of pinhole-type screens for lightfield display

The use of microlens arrays for lightfield display has the drawback of providing images with strong chromatic aliasing. To overcome this problem, pinhole-type lightfield monitors are proposed. This paper is devoted to evaluating the capability for such lightfield monitors to offer the user a convincing 3D experience with images with enough brightness and continuous aspect. Thus, we have designed a psychophysical test specifically adapted for lightfield monitors, which allowed us to confirm the usability of pinhole-type monitors

Simulation of the Effect of Different Presbyopia-Correcting Intraocular Lenses With Eyes With Previous Laser Refractive Surgery

PURPOSE: To simulate the optical performance of three presbyopia-correcting intraocular lenses (IOLs) implanted in eyes with previous laser refractive surgery. METHODS: A simulation of the through-focus modulation transfer function (MTF) was performed for three presbyopia-correcting IOLs (Mplus, Oculentis GmbH, Berlin, Germany; Symfony, Johnson & Johnson Vision, Santa Ana, CA; and Mini Well, SIFI S.p.A., Lavinaio, Italy) in one eye with previous myopic LASIK and another with hyperopic LASIK. Real topographic data and the wavefront aberration profile of each IOL obtained with a Hartmann–Shack sensor were used. RESULTS: In the eye with myopic LASIK, all IOLs lost optical quality at near and intermediate distances for 4- and 4.7-mm pupil size. For 3-mm pupil size, the Mini Well IOL showed the best intermediate and near MTF and maintained the far focus independently of the pupil. In the eye with hyperopic LASIK, the Mini Well IOL showed an intermediate, distance, and −4.00-diopter (D) foci for all pupils. The Symfony IOL showed a depth of focus at far and intermediate distance for 3-mm and a focus at −2.50 D in the rest. The Mplus showed a focus of −4.50 and −3.00 D for the 3- and 4-mm pupil, respectively. CONCLUSIONS: The Mini Well and Symfony IOLs seem to work better than the Mplus IOL in eyes with previous myopic LASIK. With previous hyperopic LASIK, the Mini Well IOL seems to be able to provide acceptable near, intermediate, and far foci for all pupil sizes. These findings should be confirmed in future clinical studies

Dos esgrafiados y dos estampillas procedentes del yacimiento Dehesa Cintruénigo III (Tarazona, Zaragoza)

El yacimiento Dehesa Cintruénigo III (Tarazona, Zaragoza) está siendo excavado por el Centro de Estudios Turiasonenses y se corresponde con un antiguo lagar que comprende una zona de pisado sobre un lacus de tipo trullo, los restos de una prensa de viga manual de tipología heroniana y un espacio de almacenaje o cella vinaria, junto con dos salas más, también destinadas al almacenaje, anexo a lo cual se vislumbra un área dedicada posiblemente a vivienda que todavía queda por investigar. En este artículo se presenta un esgrafiado paleohispánico sobre cerámica Campaniense A, dos estampillas celtibéricas sobre tinaja y un esgrafiado latino en una vasija celtibérica hallados en las dependencias de este sitio arqueológico

In Vitro Aberrometric Assessment of a Multifocal Intraocular Lens and Two Extended Depth of Focus IOLs

Purpose. To analyze the “in vitro” aberrometric pattern of a refractive IOL and two extended depth of focus IOLs. Methods. A special optical bench with a Shack-Hartmann wavefront sensor (SH) was designed for the measurement. Three presbyopia correction IOLs were analyzed: Mini WELL (MW), TECNIS Symfony ZXR00 (SYM), and Lentis Mplus X LS-313 MF30 (MP). Three different pupil sizes were used for the comparison: 3, 4, and 4.7 mm. Results. MW generated negative primary and positive secondary spherical aberrations (SA) for the apertures of 3 mm (−0.13 and +0.12 μm), 4 mm (−0.12 and +0.08 μm), and 4.7 mm (−0.11 and +0.08 μm), while the SYM only generated negative primary SA for 4 and 4.7 mm apertures (−0.12 μm and −0.20 μm, resp.). The MP induced coma and trefoil for all pupils and showed significant HOAs for apertures of 4 and 4.7 mm. Conclusions. In an optical bench, the MW induces negative primary and positive secondary SA for all pupils. The SYM aberrations seem to be pupil dependent; it does not produce negative primary SA for 3 mm but increases for higher pupils. Meanwhile, the HOAs for the MW and SYM were not significant. The MP showed in all cases the highest HOAs.This study has been partially funded by SIFI Medtech

Diseño de un curso SPOC sobre modelización matemática

Memoria ID-029. Ayudas de la Universidad de Salamanca para la innovación docente, curso 2019-2020

Monedas vivas y monedas muertas. Genealogía del dinero en la cárcel

El artículo pretende dar cuenta de la circulación de mercancías y de monedas en el ámbito carcelario, donde supuestamente el comercio y el dinero están prohibidos. A través de un trabajo etnográfico colectivo, se presentan las lógicas sociales de jerarquización de personas y de cosas que el dinero viene a objetivar. El análisis de las formas monetarias revela la dinámica social en el ámbito carcelario y las posiciones relativas que ocupan los “chorros” y lo “transas”, lo que permite ahondar en las hipótesis teóricas sobre la naturaleza de la moneda.