Search results for "dolo"
showing 10 items of 4274 documents
Registration of Surfaces Minimizing Error Propagation for a One-Shot Multi-Slit Hand-Held Scanner
2008
We propose an algorithm for the on-line automatic registration of multiple 3D surfaces acquired in a sequence by a new hand-held laser scanner. The laser emitter is coupled with an optical lens that spreads the light forming 19 parallel slits that are projected to the scene and acquired with subpixel accuracy by a camera. Splines are used to interpolate the acquired profiles to increase the sample of points and Delaunay triangulation is used to obtain the normal vectors at every point. A point-to-plane pair-wise registration method is proposed to align the surfaces in pairs while they are acquired, conforming paths and eventually cycles that are minimized once detected. The algorithm is spe…
Scale invariant line matching on the sphere
2013
International audience; This paper proposes a novel approach of line matching across images captured by different types of cameras, from perspective to omnidirectional ones. Based on the spherical mapping, this method utilizes spherical SIFT point features to boost line matching and searches line correspondences using an affine invariant measure of similarity. It permits to unify the commonest cameras and to process heterogeneous images with the least distortion of visual information.
Collision detection for 3D rigid body motion planning with narrow passages
2017
In sampling-based 3D rigid body motion planning one of the major subroutines is collision detection. Especially for problems with narrow passages many samples have to be checked by a collision detection algorithm. In this application, the runtime of the motion planning algorithm is dominated by collision detection and the samples have the very specific characteristic that many of them are in collision and have small penetration volumes. In our work, we introduce a data structure and an algorithm that makes use of this characteristic by combining well-known data structures like a distance field and an octree with the swap algorithm by Llanas et al. For 3D rigid body motion planning with narr…
Gradient-based time to contact on paracatadioptric camera
2013
International audience; The problem of time to contact or time to collision (TTC) estimation is largely discussed in perspective images. However, a few works have dealt with images of catadioptric sensors despite of their utility in robotics applications. The objective of this paper is to develop a novel model for estimating TTC with catadioptric images relative to a planar surface, and to demonstrate that TTC can be estimated only with derivative brightness and image coordinates. This model, called "gradient based time to contact", does not need high processing such as explicit estimation of optical flow and feature detection/or tracking. The proposed method allows to estimate TTC and give…
Addressing the Occlusion Problem in Augmented Reality Environments with Phantom Hollow Objects
2018
Occlusion handling is essential to provide a seamless integration of virtual and real objects in AR applications. Different approaches have been presented with a variety of technologies, environment conditions and methods. Among these methods, 3D model-based occlusion approaches have been extensively used. However, these solutions could be too time-consuming in certain situations, since they must render all the occlusion objects even though they are invisible. For this reason, we propose an inverse 3D model-based solution for handling occlusions, designed for those AR applications in which virtual objects are placed inside a real object with holes or windows. With this restriction, the occl…
Visual saliency detection in colour images based on density estimation
2017
International audience; A simple and effective method for visual saliency detection in colour images is presented. The method is based on the common observation that local salient regions exhibit distinct geometric and and texture patterns from neighbouring regions. We model the colour distribution of local image patches with a Gaussian density and measure the saliency of each patch as the statistical distance from that density. Experimental results with public datasets and comparison with other state-of-the-art methods show the effectiveness of our method.
Tracking Moving Objects With a Catadioptric Sensor Using Particle Filter
2011
International audience; Visual tracking in video sequences is a widely developed topic in computer vision applications. However, the emergence of panoramic vision using catadioptric sensors has created the need for new approaches in order to track an object in this type of images. Indeed the non-linear resolution and the geometric distortions due to the insertion of the mirror, make tracking in catadioptric images a very challenging task. This paper describes particle filter for tracking moving object over time using a catadioptric sensor. In this work different problems due to the specificities of the catadioptric systems such as geometry are considered. The obtained results demonstrate an…
Design and Calibration of a Specialized Polydioptric Camera Rig
2017
International audience; It has been observed in the nature that all creatures have evolved highly exclusive sensory organs depending on their habitat and the form of resources availability for their survival. In this project, a novel omnidirectional camera rig, inspired from natural vision sensors, is proposed. It is exclusively designed to operate for highly specified tasks in the field of mobile robotics. Navigation problems on uneven terrains and detection of the moving objects while the robot is itself in motion are the core problems that omnidirectional systems tackle. The proposed omnidirectional system is a compact and a rigid vision system with dioptric cameras that provide a 360° f…
El ?Alivio de las Indias?. la Real Hacienda Filipina, 1565-1800
2019
Previo al estudio de la Real Hacienda filipina, el trabajo se centrará en la definición del marco territorial, la función del archipiélago en la estrategia imperial y la gran transformación de finales del siglo xVIII que afectó a su situación en el conjunto colonial. En segundo lugar, se expondrá el estado de la cuestión y las principales hipótesis sobre la evolución del Tesoro filipino y los problemas que planteaba su viabilidad, así como las fuentes y la metodología empleadas. A continuación se examinarán las grandes tendencias de la Hacienda en el largo plazo y los componentes del ingreso y el gasto, para finalizar con algunas conclusiones, en especial la respuesta a la siguiente pregunt…
Creating a questionnaire for a scientific study
2016
Using questionnaires has become a permanent part of collecting data in scientific studies within the sphere of human sciences as well as other disciplines. It has been utilized already for nearly a century in collecting data. The first questionnaires were carried out on paper but nowadays there are e-questionnaires alongside it which can be carried out through e-mail or published on a social media platform (for example, Facebook). An often used method is also a survey which is carried out with a research project's own web page, association or company etc. A questionnaire has been considered as an actual scientific method of data collection since 1930s. However, it was already used a little …