Search results for "photography"
showing 10 items of 292 documents
3-Dimensional Hydrodynamic Interaction of a Supernova Remnant Shock with an Isolated Cloud
2006
We report on a computational key-project in astrophysics. The project is aimed at studying the interaction of a supernova shock wave with interstellar clouds. We describe the numerical code used, namely FLASH, a multi-dimensional astrophysical hydrodynamics code for parallel computers developed at the FLASH center (The University of Chicago); our team collaborates with, and contributes to, the FLASH project. We discuss the resources required for the whole project, the I/O management, the performance and the scalability of the code on IBM/Sp4 at CINECA. Finally, we present a selection of results. © 2005 IEEE.
Mapping Leaf Area Index with a Smartphone and Gaussian Processes
2020
Leaf area index (LAI) is a key biophysical parameter used to determine foliage cover and crop growth in environmental studies. Smartphones are nowadays ubiquitous sensor devices with high computational power, moderate cost, and high-quality sensors. A smartphone app, which is called PocketLAI, was recently presented and tested for acquiring ground LAI estimates. In this letter, we explore the use of state-of-the-art nonlinear Gaussian process regression (GPR) to derive spatially explicit LAI estimates over rice using ground data from PocketLAI and Landsat 8 imagery. GPR has gained popularity in recent years because of its solid Bayesian foundations that offer not only high accuracy but also…
Phase error analysis of clipped waveforms in surface topography measurement using projected fringes
2021
Abstract When working with the method of projected fringes outside the optical laboratory one often encounters the problem of uncontrollable ambient light. This might cause saturation of the camera which in turn results in clipping of the fringes. Since standard theories describing phase-shifting techniques assume the projected fringes to be purely sinusoidal, such clipping will result in measurement error. In this paper a detailed analysis of this problem is given, and relations between phase errors, the amount of fringe clipping and the number of phase steps are found. Moreover, the phase difference between the clipped and the unclipped fringes is described. This investigation is based on…
Dall’altra parte dello spazio. Immaginazioni surmoderne nell’iconografia di Di Donato
2017
L’articolo propone l’analisi del portfolio Nonluoghi di Michele Di Donato. Con il suo lavoro, l’artista ha proposto il suo punto di vista sui Nonluoghi descritti negli anni Novanta dall’antropologo francese Marc Augé. I nonluoghi (piazze, sala d’attesa di stazioni o aeroporti, treni o aerei, centri storici, centri commerciali, hall di alberghi e musei) sono tutti quegli spazi della contemporaneità che per il fatto di essere transitori e non identitari acquistano una dimensione altra, fondamentalmente accessibile eppure sempre labile e temporanea. Di Donato si concentra, così, sul nonluogo in quanto teoria dell’assenza, un’antropologia della solitudine, dell’impersonalità e del rimando a un …
Shaded-Mask Filtering for Extended Depth-of-Field Microscopy
2013
This paper proposes a new spatial filtering approach for increasing the depth-of-field (DOF) of imaging systems, which is very useful for obtaining sharp images for a wide range of axial positions of the object. Many different techniques have been reported to increase the depth of field. However the main advantage in our method is its simplicity, since we propose the use of purely absorbing beam-shaping elements, which allows a high focal depth with a minimum modification of the optical architecture. In the filter design, we have used the analogy between the axial behavior of a system with spherical aberration and the transverse impulse response of a 1D defocused system. This allowed us the…
Displacements measurement in a building model using the speckle photography technique
2005
The use of reduced scale models in civil engineering has made it possible to study large structures such as buildings. Using non-destructive optical techniques such as double-exposure speckle photography, extremely valuable results can be obtained, where mathematical methods are often not very exact. This work studies the model of an eighteen-storey building in which displacements can be measured at each storey of each view. It also presents a comparison of the displacement field, which was obtained with the Finite Element Method.
Determination of the object surface function by structured light: application to the study of spinal deformities.
1999
The projection of structured light is a technique frequently used to determine the surface shape of an object. In this paper, a new procedure is described that efficiently resolves the correspondence between the knots of the projected grid and those obtained on the object when the projection is made. The method is based on the use of three images of the projected grid. In two of them the grid is projected over a flat surface placed, respectively, before and behind the object; both images are used for calibration. In the third image the grid is projected over the object. It is not reliant on accurate determination of the camera and projector pair relative to the grid and object. Once the met…
Docentes paseando por las letras de la ciudad
2013
En el presente artículo planteamos una nueva mirada hacia la ciudad y tanteamos geografías aptas para crear escenarios de aprendizaje. Las letras urbanas constituyen un argumento cultural que puede ayudarnos a reinterpretar el tejido patrimonial. Con la tipografía los educadores y las educadoras disponen de un poderoso referente gráfico capaz de articular el complejo entramado comunicativo de lo urbano. Reivindicamos aquí el andar como práctica estética, y el paseo por la ciudad como resorte cultural muy adecuado para motivar a nuestro alumnado. Siguiendo la ruta de las letras encontramos trayectorias que nos conducen al arte, al patrimonio, a la literatura, a la fotografía, y muy especialm…
Enhancing visual literacy through interpretation of photo-genres: toward a genre typology of journalistic photographs
2016
ABSTRACTAlthough genre is one of the most extensively employed concepts in various disciplines, only a few attempts have been made to classify images in the press, providing either a palette of thematic categories similar to those of photography competitions or theory-based classifications, which often ignore certain types of photographs. In addition, no studies have suggested the genre typology as a tool for the interpretation of journalistic photographs. Based on a literature review and visual material analysis from the Polish daily Gazeta Wyborcza, this study compiles a typology that sets out four photo-genres: news photography, reportage photography, portrait photography and illustrativ…
Protocolo técnico para la fotografía de fuentes filológicas primarias
2014
con fines documentales, proyectado para garantizar la máxima fidelidad posible al motivo original representado. Tras una descripción detallada del material necesario, seleccionado específicamente en función de las necesidades particulares de la fotografía de textos manuscritos o impresos, se desarrolla un procedimiento adaptado a las nuevas circunstancias de la fotografía digital, concebido en dos fases: la captación de la imagen en formato RAW, y su posterior edición. En este estudio se trata la primera parte, describiendo sistemáticamente, paso a paso, las decisiones técnicas relativas a los ajustes fotográficos de la toma en diferentes situaciones lumínicas, encaminadas a maximizar la ca…