Search results for "Computer Graphics"
showing 10 items of 530 documents
Accurate estimation of retinal vessel width using bagged decision trees and an extended multiresolution Hermite model.
2012
We present an algorithm estimating the width of retinal vessels in fundus camera images. The algorithm uses a novel parametric surface model of the cross-sectional intensities of vessels, and ensembles of bagged decision trees to estimate the local width from the parameters of the best-fit surface. We report comparative tests with REVIEW, currently the public database of reference for retinal width estimation, containing 16 images with 193 annotated vessel segments and 5066 profile points annotated manually by three independent experts. Comparative tests are reported also with our own set of 378 vessel widths selected sparsely in 38 images from the Tayside Scotland diabetic retinopathy scre…
Air-Coupled Imaging Method Applied to the Study and Conservation of Paintings
2007
An air-coupled acoustical imaging method for the study of wooden panel paintings is presented. After a brief overview of the state of the art, an introduction is given regarding the production technique of the art object under investigation. The technology employed is described in detail, as well as the proposed method. After a feasibility campaign of experiments, real ancient paintings have been investigated by means of a through-transmission and a single-sided lay-out. Defects were imaged in all the objects examined and in both the configurations adopted
Virtual reality treatment of flying phobia.
2002
Flying phobia (FP) might become a very incapacitating and disturbing problem in a person's social, working, and private areas. Psychological interventions based on exposure therapy have proved to be effective, but given the particular nature of this disorder they bear important limitations. Exposure therapy for FP might be excessively costly in terms of time, money, and efforts. Virtual reality (VR) overcomes these difficulties as different significant environments might be created, where the patient can interact with what he or she fears while in a totally safe and protected environment, the therapist's consulting room. This paper intends, on one hand, to show the different scenarios desig…
Using Augmented Reality to Treat Phobias
2005
Virtual reality (VR) is useful for treating several psychological problems, including phobias such as fear of flying, agoraphobia, claustrophobia, and phobia to insects and small animals. We believe that augmented reality (AR) could also be used to treat some psychological disorders. AR and VR share some advantages over traditional treatments. However, AR gives a greater feeling of presence (the sensation of being there) and reality judgment (judging an experience as real) than VR because the environment and the elements the patient uses to interact with the application are real. Moreover, in AR users see their own hands, feet, and so on, whereas VR only simulates this experience. With thes…
Mono-stereo-autostereo: the evolution of 3-dimensional neurosurgical planning.
2012
BACKGROUND: In the past decade, surgery planning has changed significantly. The main reason is the improvements in computer graphical rendering power and display technology, which turned the plain graphics of the mid-1990s into interactive stereoscopic objects. OBJECTIVE: To report our experiences with 2 virtual reality systems used for planning neurosurgical operations. METHODS: A series of 208 operations were planned with the Dextroscope (Bracco AMT, Singapore) requiring the use of liquid crystal display shutter glasses. The participating neurosurgeons answered a questionnaire after the planning procedure and postoperatively. In a second prospective series of 33 patients, we used an autos…
Scratches Removal in Digitised Aerial Photos Concerning Sicilian Territory
2007
In this paper we propose a fast and effective method to detect and restore scratches in aerial photos from a photographic archive concerning Sicilian territory. Scratch removal is a typical problem for old movie films but similar defects can be seen in still images. Our solution is based on a semiautomatic detection process and an unsupervised restoration algorithm. Results are comparable with those obtained with commercial restoration tools.
New observations on a pottery fragment with incised deer from the Cova de lâOr (Beniarés, Alacant)
2007
The red external surface of a vessel, decorated with an incised group of deer from Cova de l’Or, has been long considered characteristic of the application of the almagra technique. However, the results of the elemental analysis of this fragment, compared with the results of another vessel with almagra decoration from the same site, call into question the application of this technique in the first vessel. In addition, searching for parallels for the schematic incised motifs of the vessel, in both ceramic decorations and rock art, we have concluded that rather than deer the represented animals are hinds.
Documenting carved stones from 3D models. Part II - Ambient occlusion to reveal carved parts.
2021
10 pages; International audience; Revealing carved parts in rock art is of primary importance and remains a major challenge for archaeological documentation. Computational geometry applied to 3D imaging provides a unique opportunity to document rock art. This study evaluates five algorithms and derivatives used to compute ambient occlusion and sky visibility on 3D models of Mongolian stelae, also known as deer stones. By contrast with the previous companion work, models are processed directly in 3D, without preliminary projection. Volumetric obscurance gives the best results for the identification of carved figures. The effects of model resolution and parameters specific to ambient occlusio…
Digital Mosaic Frameworks - an overview
2007
Art often provides valuable hints for technological innovations especially in the field of Image Processing and Computer Graphics. In this paper we survey in a unified framework several methods to transform raster input images into good quality mosaics. For each of the major different approaches in literature the paper reports a short description and a discussion of the most relevant issues. To complete the survey comparisons among the different techniques both in terms of visual quality and computational complexity are provided.
<title>Real-time face tracking and recognition for video conferencing</title>
2001
This paper describes a system of vision in real time, allowing to detect automatically the faces presence, to localize and to follow them in video sequences. We verify also the faces identities. These processes are based by combining technique of image processing and methods of neural networks. The tracking is realized with a strategy of prediction-verification using the dynamic information of the detection. The system has been evaluated quantitatively on 8 video sequences. The robustness of the method has been tested on various lightings images. We present also the analysis of complexity of this algorithm in order to realize an implementation in real time on a FPGA based architecture.