Search results for "rendering"
showing 10 items of 138 documents
Regularized multiresolution spatial unmixing for ENVISAT/MERIS and landsat/TM image fusion
2011
Earth observation satellites currently provide a large volume of images at different scales. Most of these satellites provide global coverage with a revisit time that usually depends on the instrument characteristics and performance. Typically, medium-spatial-resolution instruments provide better spectral and temporal resolutions than mapping-oriented high-spatial-resolution multispectral sensors. However, in order to monitor a given area of interest, users demand images with the best resolution available, which cannot be reached using a single sensor. In this context, image fusion may be effective to merge information from different data sources. In this letter, an image fusion approach ba…
The impact of irreversible image data compression on post-processing algorithms in computed tomography
2020
PURPOSE: We aimed to evaluate the influence of irreversible image compression at varying levels on image post-processing algorithms (3D volume rendering of angiographs, computer-assisted detection of lung nodules, segmentation and volumetry of liver lesions, and automated evaluation of functional cardiac imaging) in computed tomography (CT). METHODS: Uncompressed CT image data (30 angiographs of the lower limbs, 38 lung exams, 20 liver exams and 30 cardiac exams) were anonymized and subsequently compressed using the JPEG2000 algorithm with compression ratios of 8:1, 10:1, and 15:1. Volume renderings of CT angiographies obtained from compressed and uncompressed data were compared using objec…
Studies of methods and tools for the really mixed visual coherence applied to the patrimony
2013
The work described in this report has as a target the mixed reality device ray-on, developed by the on-situ company. This device, dedicated to cultural heritage and specifically architectural heritage, is meant to be installed on-site and shows the user an uchronic view of its surroundings. As the chosen stance is to display photo-realistic images, two trails were followed: the improvement of the real-virtual merging by reproducing accurately the real lighting on the virtual objects, and the development of a real-time segmentation method which is resilient to lighting changes.Regarding lighting reproduction, an image-based rendering method is used in addition to a high dynamic range capture…
Depth rendering of large incoherent scenes from integral images
2016
Integral imaging is a technique that provides the spatial and angular information of three-dimensional (3D) scenes through a single shot. Taking advantage of this capability, different applications have been developed. Some of these applications are the 3D display and digital post-processing, in particular depth-reconstruction from integral images.
Acoustic rendering of particle-based simulation of liquids in motion
2009
In interaction and interface design, the representation of continuous processes often uses liquid metaphors, such as dripping or streaming. When an auditory display of such processes is required, an approach to sound-synthesis based on the physics of liquids in motion would be the most convincing, especially when real-time interaction is into play. In order to bridge the complexity of fluid-dynamic simulations with the needs of interactive sonification, we propose a multi-rate sound synthesis of liquid phenomena. Low-rate smoothed-particle hydrodynamics is used to model liquids in motion and to trigger sound-emitting events. Such events, such as solid-liquid collision, or bubble formation, …
Capabilities and Affordances of Virtual Worlds for People with Lifelong Disability
2013
Using technology is of great value for people with lifelong disability (PWLD). The Internet can help PWLD to be more independent, to be socially active, and to participate in a range of activities. Virtual worlds (VWs) offer an environment with technology capabilities for interaction, rendering, and communication. The ability to take advantage of these capabilities may depend on the technology and the ability of the person utilizing it. Using a qualitative study we aimed to explore the differences of ability required to use these capabilities and make capabilities into affordances for PWLD. We found there were differences in PWLD’s ability to utilize the capabilities offered and conclude th…
Architecture-Driven Level Set Optimization: From Clustering to Sub-pixel Image Segmentation
2016
Thanks to their effectiveness, active contour models (ACMs) are of great interest for computer vision scientists. The level set methods (LSMs) refer to the class of geometric active contours. Comparing with the other ACMs, in addition to subpixel accuracy, it has the intrinsic ability to automatically handle topological changes. Nevertheless, the LSMs are computationally expensive. A solution for their time consumption problem can be hardware acceleration using some massively parallel devices such as graphics processing units (GPUs). But the question is: which accuracy can we reach while still maintaining an adequate algorithm to massively parallel architecture? In this paper, we attempt to…
SEMI-AUTOMATIC VOLUMETRIC SEGMENTATION OF THE UPPER AIRWAYS IN PATIENTS WITH PIERRE ROBIN SEQUENCE
2014
Pierre Robin malformation is a rare craniofacial dysmorphism whose pathogenesis is multifactorial. Although there is some agreement in non-invasive treatment in less severe cases, the dispute is still open on cases with severe respiratory impairment. We present a semi-automatic novel diagnostic tool for calculating upper airway volume, in order to eventually address surgery in patients with Pierre Robin Sequence (PRS). Multidetector CT datasets of two patients and two controls were tested to assess the proposed method for ROI segmentation, upper airway volume computation and three-dimensional reconstructions. The experimental results show an irregular pattern and a severely reduced cross-s…
Imaging processing for CT angiography of the cervicocranial arteries: evaluation of reformatting technique.
2007
Purpose. The aim of this study was to compare computed tomography angiography (CTA) sliding-thin-slab (STS) multiplanar reformatting (MPR), STS maximum intensity projection (MIP) and three-dimensional (3D) volume rendering (VR) reformatting techniques in the evaluation of cervicocranial arteries. Materials and methods. Twenty patients examined with multislice CT were included in this study. CTA images were reformatted as STS-MIP, STS-MPR and 3DVR in orthogonal planes and in the oblique-coronal plane. Images were evaluated in consensus by two radiologists, with a third radiologist to resolve discordances in grading image quality parameters. The Spearman correlation analysis was performed to …
Frequency-Downconversion Stability of PMMA Coatings in Hybrid White Light-Emitting Diodes
2015
We report on the properties of a poly(methyl methacrylate)-based coating used as a host for an organic dye in hybrid white light-emitting diodes. The device is composed by a pump source, which is a standard inorganic GaN/InGaN blue light-emitting diode (LED) emitting at around 450 nm, and a spin-coated conversion layer making use of Lumogen® F Yellow 083. Under prolonged irradiation, the coating exhibits significant bleaching, thus degrading the color rendering performance of the LED. We present experimental results that confirm that the local temperature rise of the operating diode does not affect the conversion layer. It is also proven that, during the test, the photostability of the orga…