Search results for " pattern"
showing 10 items of 2245 documents
SAMSLAM: Simulated Annealing Monocular SLAM
2013
This paper proposes a novel monocular SLAM approach. For a triplet of successive keyframes, the approach inteleaves the registration of the three 3D maps associated to each image pair in the triplet and the refinement of the corresponding poses, by progressively limiting the allowable reprojection error according to a simulated annealing scheme. This approach computes only local overlapping maps of almost constant size, thus avoiding problems of 3D map growth. It does not require global optimization, loop closure and back-correction of the poses.
Designing the 5G network infrastructure: a flexible and reconfigurable architecture based on context and content information
2018
5G networks will have to offer extremely high volumes of content, compared to those of today’s. Moreover, they will have to support heterogeneous traffics, including machine-to-machine, generated by a massive volume of Internet-of-Things devices. Traffic demands will be variable in time and space. In this work, we argue that all this can be achieved in a cost-effective way if the network is flexible and reconfigurable. We present the Flex5Gware network architecture, designed to meet the above requirements. Moreover, we discuss the links between flexibility and reconfigurability, on the one side, and context awareness and content awareness, on the other; we show how two of the building…
Video Viewing Patterns Using Different Teaching Treatments: A Case Study Using YouTube Analytics
2019
Aquest estudi explora els patrons de visualització de 17 vídeos en un context tradicional daprenentatge i en un context de classe invertida per 723 estudiants de negocis cursant un mòdul relacionat amb . Mentre recerques anteriors s?han centrat principalment en resultats (per exemple, satisfacció/resultats dels alumnes), en aquest estudi l?enfocament recau en com la natura de les interaccions del estudiants amb el vídeos por determinar-se mitjançant un anàlisi profund de les dades analítiques. Els nostres resultats mostren menys interacció amb els vídeos en el context de la classe invertida que en el de la classe tradicional. De la mateixa manera, mostren un ús més elevat dels vídeos com a …
Effects of Long-Term Habitat Protection on Montane Small Mammals: Are Sorex araneus and S. minutus More Sensitive Than Previously Considered?
2022
Protection of natural areas by restricting human activities aims to preserve plant and animal populations and whole communities, ensuring the conservation of biological diversity and enhancement of ecosystem services. Therefore, it is expected that the longer the protection, the stronger the desired effects. We evaluated the responses of small mammals at the population and community levels under protection in the southern Carpathian Mountains. We surveyed small mammals for five years in sites with long- and short-term protection and non-protected. Besides protection status, we included elevation, habitat heterogeneity, and the month of survey as predictors in our models. As response variabl…
3D reconstruction of hot metallic surfaces for industrial part characterization
2009
During industrial forging of big hot metallic shells, it is necessary to regularly measure the dimensions of the parts, especially the inner and outer diameters and the thickness of the walls, in order to decide when to stop the forging process. The inner and outer diameters of the shells range from 4 to 6 meters and to measure them a large ruler is placed horizontally at the end of the shell. Two blacksmiths standing on each side of the ruler at about ten meters from it visually reads the graduations on the ruler in order to determine the inner and outer diameters from which the thickness of the wall is determined. This operation is carried out several times during a forging process and it…
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…
Archetypal analysis: an alternative to clustering for unsupervised texture segmentation
2019
Texture segmentation is one of the main tasks in image applications, specifically in remote sensing, where the objective is to segment high-resolution images of natural landscapes into different cover types. Often the focus is on the selection of discriminant textural features, and although these are really fundamental, there is another part of the process that is also influential, partitioning different homogeneous textures into groups. A methodology based on archetype analysis (AA) of the local textural measurements is proposed. AA seeks the purest textures in the image and it can find the borders between pure textures, as those regions composed of mixtures of several archetypes. The prop…
Automatic detection and classification of retinal vascular landmarks
2014
The main contribution of this paper is introducing a method to distinguish between different landmarks of the retina: bifurcations and crossings. The methodology may help in differentiating between arteries and veins and is useful in identifying diseases and other special pathologies, too. The method does not need any special skills, thus it can be assimilated to an automatic way for pinpointing landmarks; moreover it gives good responses for very small vessels. A skeletonized representation, taken out from the segmented binary image (obtained through a preprocessing step), is used to identify pixels with three or more neighbors. Then, the junction points are classified into bifurcations or…
Estimation of fibre orientation from digital images
2001
In this paper, estimation of fibre orientation is studied for fibre systems observable as a blurred greyscale image. The estimation method is based on scaled variograms observed along a set of sampling lines in different directions. The parameters of the orientation distribution are obtained numerically. Simulated data are used to study the statistical properties of the method.
An Augmented Reality System for the Treatment of Acrophobia: The Sense of Presence Using Immersive Photography
2006
This paper describes an augmented reality (AR) system for the treatment of acrophobia. First, the technical characteristics of the original prototype are described. Second, the capacity of the immersive photography used in the AR system to provoke sense of presence in users is tested. Forty-one participants without fear of heights walked around a staircase in both a real environment and an immersive photography environment. Immediately after their experience, participants were given the SUS questionnaire to assess their subjective sense of presence. The users' scores in the immersive photography were very high. Results indicate that the acrophobic context can be useful for the treatment of…