Search results for " Cameras"
showing 10 items of 30 documents
Extract information of polarization imaging from local matching stereo
2010
Since polarization of light was used in the field of computer vision, the research of polarization vision is rapidly growing. Polarization vision has been shown to simplify some important image understanding tasks that can be more difficult to be performed with intensity vision. Furthermore, it has computational efficiency because it only needs grayscale images and can be easily applied by a simple optical setup. Nowadays, we can find various types of polarization cameras in the market. However, they are very expensive. In our work, we will study and develop a low price polarization camera setup with parallel acquisition using a stereo system. This system requires only two general cameras e…
Camera-based measurement of relative image contrast in projection displays
2013
International audience; This research investigated the measured contrast of projection displays based on pictures taken by un-calibrated digital cameras under typical viewing conditions. A high-end radiometer was employed as a reference to the physical response of projection luminance. Checkerboard, gray scale and color complex test images with a range of the projector's brightness and contrast settings were projected. Two local and two global contrast metrics were evaluated on the acquired pictures. We used contrast surface plots and Pearson correlation to investigate the measured contrast versus the projector's brightness and contrast settings. The results suggested, as expected, the proj…
Compressive holography with a single-pixel detector.
2013
This Letter develops a framework for digital holography at optical wavelengths by merging phase-shifting interferometry with single-pixel optical imaging based on compressive sensing. The field diffracted by an input object is sampled by Hadamard patterns with a liquid crystal spatial light modulator. The concept of a single-pixel camera is then adapted to perform interferometric imaging of the sampled diffraction pattern by using a Mach-Zehnder interferometer. Phase-shifting techniques together with the application of a backward light propagation algorithm allow the complex amplitude of the object under scrutiny to be resolved. A proof-of-concept experiment evaluating the phase distributio…
Everyday Appropriations of Information Technology: A Study of Creative Uses of Digital Cameras
2011
Repurposive appropriation is a creative everyday act in which a user invents a novel use for information technology (IT) and adopts it. This study is the first to address its prevalence and predictability in the consumer IT context. In all, 2,379 respondents filled in an online questionnaire on creative uses of digital cameras, such as using them as scanners, periscopes, and storage media. The data reveal that such creative uses are adopted by about half of the users, on average, across different demographic backgrounds. Discovery of a creative use on one's own is slightly more common than is learning it from others. Most users discover the creative uses either completely on their own or wh…
Enabling Technologies on Hybrid Camera Networks for Behavioral Analysis of Unattended Indoor Environments and Their Surroundings
2008
This paper presents a layered network architecture and the enabling technologies for accomplishing vision-based behavioral analysis of unattended environments. Specifically the vision network covers both the attended environment and its surroundings by means of multi-modal cameras. The layer overlooking at the surroundings is laid outdoor and tracks people, monitoring entrance/exit points. It recovers the geometry of the site under surveillance and communicates people positions to a higher level layer. The layer monitoring the unattended environment undertakes similar goals, with the addition of maintaining a global mosaic of the observed scene for further understanding. Moreover, it merges …
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…
Ash-plume dynamics and eruption source parameters by infrasound and thermal imagery: The 2010 Eyjafjallajökull eruption
2013
During operational ash-cloud forecasting, prediction of ash concentration and total erupted mass directly depends on the determination of mass eruption rate (MER), which is typically inferred from plume height. Uncertainties for plume heights are large, especially for bent-over plumes in which the ascent dynamics are strongly affected by the surrounding wind field. Here we show how uncertainties can be reduced if MER is derived directly from geophysical observations of source dynamics. The combination of infrasound measurements and thermal camera imagery allows for the infrasonic type of source to be constrained (a dipole in this case) and for the plume exit velocity to be calculated (54–14…
Visual Control of a Robotic Hand
2004
The paper deals with the design and implementation of a visual control of a robotic system composed of a dexterous hand and stereo cameras. The aim of the proposed system is to reproduce the movements of a human hand in order to learn complex manipulation tasks. A novelty algorithm for a robust and fast fingertips localization and tracking is presented. Moreover, a simulator is integrated in the system to give useful feedbacks to the users during operations, and provide robust testing framework for real experiments (see video).
Improving Image Quality in a multi-plane Compton Telescope for Hadron Therapy Monitoring
2023
Esta disertación explora diferentes técnicas para mejorar la calidad de las imágenes obtenidas con cámaras Compton. Tal mejora es una de las necesidades principales que obstaculizan la aplicación de cámaras Compton como herramientas para la verificación en tiempo real de terapia hadrónica, a través de la obtención de imágenes de distribuciones espaciales de emisión rápida de rayos gamma emitidos como subproductos de las interacciones de estos hadrones en el paciente. Esta aplicación presenta importantes dificultades, pues requiere medir rayos gamma de energías relativamente altas emitidos en un rango de energías amplio y junto a otras partículas no deseadas. Además, la cámara Compton debe s…
3-D shape reconstruction in an active stereo vision system using genetic algorithms
2003
Abstract The recovery of 3-D shape information (depth) using stereo vision analysis is one of the major areas in computer vision and has given rise to a great deal of literature in the recent past. The widely known stereo vision methods are the passive stereo vision approaches that use two cameras. Obtaining 3-D information involves the identification of the corresponding 2-D points between left and right images. Most existing methods tackle this matching task from singular points, i.e. finding points in both image planes with more or less the same neighborhood characteristics. One key problem we have to solve is that we are on the first instance unable to know a priori whether a point in t…