New method of microimages generation for 3D display

In this paper, we propose a new method for the generation of microimages, which processes real 3D scenes captured with any method that permits the extraction of its depth information. The depth map of the scene, together with its color information, is used to create a point cloud. A set of elemental images of this point cloud is captured synthetically and from it the microimages are computed. The main feature of this method is that the reference plane of displayed images can be set at will, while the empty pixels are avoided. Another advantage of the method is that the center point of displayed images and also their scale and field of view can be set. To show the final results, a 3D InI display prototype is implemented through a tablet and a microlens array. We demonstrate that this new technique overcomes the drawbacks of previous similar ones and provides more flexibility setting the characteristics of the final image

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

Machine Learning-Based View Synthesis in Fourier Lightfield Microscopy

Current interest in Fourier lightfield microscopy is increasing, due to its ability to acquire 3D images of thick dynamic samples. This technique is based on simultaneously capturing, in a single shot, and with a monocular setup, a number of orthographic perspective views of 3D microscopic samples. An essential feature of Fourier lightfield microscopy is that the number of acquired views is low, due to the trade-off relationship existing between the number of views and their corresponding lateral resolution. Therefore, it is important to have a tool for the generation of a high number of synthesized view images, without compromising their lateral resolution. In this context we investigate here the use of a neural radiance field view synthesis method, originally developed for its use with macroscopic scenes acquired with a moving (or an array of static) digital camera(s), for its application to the images acquired with a Fourier lightfield microscope. The results obtained and presented in this paper are analyzed in terms of lateral resolution and of continuous and realistic parallax. We show that, in terms of these requirements, the proposed technique works efficiently in the case of the epi-illumination microscopy mode

GPU-accelerated integral imaging and full-parallax 3D display using stereo-plenoptic camera system

In this paper, we propose a novel approach to produce integral images ready to be displayed onto an integral- imaging monitor. Our main contribution is the use of commercial plenoptic camera, which is arranged in a stereo configuration. Our proposed set-up is able to record the radiance, spatial and angular, information simultaneously in each different stereo position. We illustrate our contribution by composing the point cloud from a pair of captured plenoptic images, and generate an integral image from the properly registered 3D information. We have exploited the graphics processing unit (GPU) acceleration in order to enhance the integral-image computation speed and efficiency. We present our approach with imaging experiments that demonstrate the improved quality of integral image. After the projection of such integral image onto the proposed monitor, 3D scenes are displayed with full-parallax

3D Integral Microscopy based in far-field detection

Lately, Integral-Imaging systems have shown very promising capabilities of capturing the 3D structure of microscopic and macroscopic scenes. The aim of this work is to provide an optimal design for 3D-integral microscopy with extended depth of eld and enhanced lateral resolution. By placing an array of microlenses at the aperture stop of the objective, this setup provides a set of orthographic views of the 3D sample. Adopting well known integral imaging reconstruction algorithms it can be shown that the depth of eld as well as spatial resolution are improved with respect to conventional integral microscopy imaging. Our claims are supported on theoretical basis and experimental images of a resolution test target, and biological samples

Capture and visualization of biological 3D samples through lightfield imaging and display techniques

La microscopía óptica convencional proporciona imágenes de alta resolución de muestras microscópicas. Sin embargo, su escasa profundidad de campo y su falta de seccionado óptico hacen que sea inadecuada para la observación de especímenes tridimensionales. Para solucionar este problema, se han propuesto varias técnicas de microscopía 3D, la mayoría de ellas basadas en procedimientos de escaneo. La microscopía lightfield, en cambio, es una técnica de reciente desarrollo, que es capaz de capturar información 3D de muestras gruesas en una sola toma. Esto se consigue registrando de forma simultánea la información espacial y angular de los rayos procedentes de cada punto del objeto. Esta característica hace que los sistemas lightfield sean aptos para la observación de muestras biológicas vivas, que son generalmente gruesas y dinámicas. La microscopía lightfield es una aplicación de la fotografía integral, una técnica inventada en la primera década del siglo XX, que estaba basada en capturar múltiples perspectivas de una escena 3D y proyectarlas para obtener una reconstrucción 3D de la misma. Gracias a los extraordinarios avances en las tecnologías optoelectrónicas, la fotografía integral ha despertado un interés creciente en los últimos veinte años. Una prueba de ello es el hecho que se han fundado varias empresas que comercializan cámaras fotográficas basadas en el concepto de fotografía integral. Respecto a la microscopía lightfield, diferentes grupos de investigación de óptica e informática trabajan en investigar mejoras en el sistema óptico y en los algoritmos para la extracción de la imagen 3D a partir del mapa espacio-angular capturado. Sin embargo, a menudo el uso de la microscopía lightfield está limitado al ámbito académico. La motivación del trabajo que se presenta en esta tesis ha sido la de aprovechar el potencial de la microscopía lightfield y extender su uso fuera del ámbito académico, entre los usuarios generales de microscopio. El objetivo es el de estandarizar el uso de la tecnología lightfield en aquellas aplicaciones en las que tanto la información 3D como la resolución temporal son imprescindibles. En estos casos, la microscopía lightfield representa una solución perfecta. En esta tesis, se analiza el estado del arte de la microscopía lightfield, para evaluar sus prestaciones y limitaciones intrínsecas. Basándose en este análisis, se presenta el ocular plenóptico, un dispositivo capaz de convertir cualquier microscopio óptico convencional en un microscopio lightfield de Fourier. El ocular plenóptico desarrollado es un dispositivo comercial de propósito general, que puede demostrar la viabilidad de la técnica para la observación de muestras tridimensionales dinámicas en distintos campos. A continuación, se presenta un protocolo para la reconstrucción 3D de las muestras capturadas con el ocular plenóptico, que proporciona seccionado óptico computacional y optimiza los tiempos de computación de la imagen 3D. Finalmente, se demuestra la aplicación del concepto de fotografía integral a la visualización 3D de las muestras con un monitor lightfield. En particular, se presenta un algoritmo para la generación de imágenes para este tipo de monitores, que se puede aplicar tanto para muestras microscópicas como para escenas macroscópicas. Con el trabajo presentado en esta tesis, hemos sentado las bases para una difusión masiva de la microscopía lightfield, implementando un dispositivo compacto y desarrollando los algoritmos óptimos en términos de prestaciones, flexibilidad y robustez

Robust Depth Estimation for Light Field Microscopy

Light field technologies have seen a rise in recent years and microscopy is a field where such technology has had a deep impact. The possibility to provide spatial and angular information at the same time and in a single shot brings several advantages and allows for new applications. A common goal in these applications is the calculation of a depth map to reconstruct the three-dimensional geometry of the scene. Many approaches are applicable, but most of them cannot achieve high accuracy because of the nature of such images: biological samples are usually poor in features and do not exhibit sharp colors like natural scene. Due to such conditions, standard approaches result in noisy depth maps. In this work, a robust approach is proposed where accurate depth maps can be produced exploiting the information recorded in the light field, in particular, images produced with Fourier integral Microscope. The proposed approach can be divided into three main parts. Initially, it creates two cost volumes using different focal cues, namely correspondences and defocus. Secondly, it applies filtering methods that exploit multi-scale and super-pixels cost aggregation to reduce noise and enhance the accuracy. Finally, it merges the two cost volumes and extracts a depth map through multi-label optimization

Some reflections on neuroscience and civil law

This chapter is about some prospects opened up by neurosciences for the current civil law. Just think about the discovery of the mirror-neurons and the possible use of it in the negotiation (it imposes the protection of self-determination and consensus of the contracting party); or about the consequences deriving from neuro-scientific knowledge for the notion of legal capacity (or actual abilities) of natural persons. This provides a good guess of how valuable the neuro-scientific knowledge could be for the more effective and efficient protection of the human dignity

Chasing Gravitational Waves with the Chereknov Telescope Array

Presented at the 38th International Cosmic Ray Conference (ICRC 2023), 2023 (arXiv:2309.08219)2310.07413International audienceThe detection of gravitational waves from a binary neutron star merger by Advanced LIGO and Advanced Virgo (GW170817), along with the discovery of the electromagnetic counterparts of this gravitational wave event, ushered in a new era of multimessenger astronomy, providing the first direct evidence that BNS mergers are progenitors of short gamma-ray bursts (GRBs). Such events may also produce very-high-energy (VHE, > 100GeV) photons which have yet to be detected in coincidence with a gravitational wave signal. The Cherenkov Telescope Array (CTA) is a next-generation VHE observatory which aims to be indispensable in this search, with an unparalleled sensitivity and ability to slew anywhere on the sky within a few tens of seconds. New observing modes and follow-up strategies are being developed for CTA to rapidly cover localization areas of gravitational wave events that are typically larger than the CTA field of view. This work will evaluate and provide estimations on the expected number of of gravitational wave events that will be observable with CTA, considering both on- and off-axis emission. In addition, we will present and discuss the prospects of potential follow-up strategies with CTA