Search results for "SCANNER"
showing 10 items of 170 documents
Online dimensional control of rolled steel profiles using projected fringes
2020
AbstractFringe projection is a versatile method for mapping the topography of surfaces. In this paper, it is used to measure the defects on the head of railroad rails while the rails are moving. Railroad rails are made by hot rolling. The quality of the finished product is generally good, but surface texture will deteriorate with increasing temperature. A method for online inspection therefore is very desirable. In the present experiment, dimensional inspection of the railroad rails was made online while moving at a speed of 1–2 m/s. Therefore, it is important to minimize the registration time. To achieve this, we apply a method of fringe location with sub-pixel accuracy that requires only …
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…
Simple Large Scale 3D scanner
2019
Abstract A new 3D measuring device for large dimensions is proposed. It is based on the combination of a simple system consisting of a smartphone that measures in stereo a near field with a robotic total station that tracks the position of the camera on a far field. The calibration method is described and the metrological properties obtained make it possible to measure objects of several tens or even hundreds of meters long with errors of the order of a millimeter. This makes it possible to consider the use of the system for many industrial applications
Fast Inertia-Free Volumetric Light-Sheet Microscope
2017
Fast noninvasive three-dimensional (3D) imag-ing is crucial for quantitatively studying highly dynamic events ranging from flow cytometry to developmental biology. Light-sheet microscopy has emerged as the tool-of-choice for 3D characterization of rapidly evolving systems. However, to obtain a 3D image, either the sample or parts of the microscope are moved, limiting the acquisition speed. Here, we propose a novel inertia-free light-sheet-based scheme for volumetric imaging at high temporal resolution. Our approach comprises a novel combination of an acousto-optic scanner to produce tailored illumination and an acoustic-optofluidic lens, placed in the detection path to provide extended dept…
Influence of the metaphysis positioning in a new reverse shoulder prosthesis
2016
Aim of this work is to investigate the behaviour of a new reverse shoulder prosthesis, characterized by a humeral metaphysis with a variable offset, designed to increase the range of movements and to reduce the impingement. In particular, by means of virtual prototypes of the prosthesis, different offset values of the humeral metaphysis have been analysed in order to find the best positioning able to maximize the range of movements of the shoulder joint. The abduction force of the deltoid, at different offset values, has been also estimated. The study has been organized as follows. In the first step, the point clouds of the surfaces of the different components of the prosthesis have been ac…
A coarse to fine 3D acquisition system
2015
International audience; The 3D chain (acquisition-processing-compression) is , most of the time , sequenced into several steps. Such approaches result into an one-dense acquisition of 3D points. In large scope of applications , the first processing step consists in simplifying the data. In this paper , we propose a coarse to fine acquisition system which permits to obtain simplified data directly from the acquisition. By calculating some complementary information from 2D images , such as 3D normals , multiple homogeneous regions will be segmented and affected to a given primitive class. Contrary to other studies , the whole process is not based on a mesh. The obtained model is simplified di…
La Cappella Palatina di Palermo: Misura, Interpretazione, Rappresentazione
2012
Lo studio che segue è incentrato sull'analisi delle vicende costruttive della Cappella Palatina nel Palazzo Reale di Palermo, costruita per volontà di Ruggero II nella prima metà del XII secolo. La peculiarità della Cappella è quella di aver mantenuto pressoché inalterato i caratteri spaziali dell’interno attraverso i secoli; tale peculiarità ha fatto si che la Cappella sia stata oggetto di studi molto approfonditi condotti da storici dell’arte a partire dalla del XIX secolo fino ai nostri giorni. Lo studio intende porsi come contributo alla conoscenza della Cappella, alla interpretazione di alcune questioni rimaste irrisolte, come stimolo ausiliare per successivi studi, attraverso gli stru…
GEOMATIC TECHNIQUES FOR THE COLONNADE STRUCTURAL ANALYSIS OF THE HISTORICAL “ CHIARAMONTE STERI” BUILDING
2019
The monitoring of building structures has an increasingly important role in the engineering field, above all because they are concerned with the impact that such structures have in the area where they were built. Often, when walking through the old town centres, we realize just how obsolete and dangerous some buildings (even historic-cultural ones) are. The interest of some local governments in this problem has led, in the last few years, to the study and the trying out of measuring and monitoring methods which, quickly and at low cost, allow to define the extent of the deformation and the degrade in an accurate and reliable way. The Courtyard of “Palazzo Steri - Chiaramonte” is composed of…
TECNOLOGIE DI RILIEVO 3D PER LA DOCUMENTAZIONE, L’INTERPRETAZIONE E LA VALORIZZAZIONE DEL PATRIMONIO ARCHEOLOGICO: IL CASO STUDIO DEL PARCO ARCHEOLOG…
2020
In recent decades, the application of geomatics technologies and methodologies to archaeological studies has led to a substantial change in onsite survey techniques and allowed an interdisciplinary approach between archaeology and digital technologies. The employment of these techniques aims to reduce the time of research and documentation, to acquire large amounts of data and to manage, in a more efficiently and quickly way, different datasets. Moreover, these new approaches provide non-invasive, flexible, low-cost methodologies to improve archaeological documentation from a quantitative and qualitative point of view. Nowadays, archaeologists can take advantage of various recording techniq…
Study of a High-Resolution PET System Using a Silicon Detector Probe
2015
253 páginas. Tesis Doctoral del Departamento de Física Atómica, Molecular y Nuclear de la Universidad de Valencia y del Instituto de Física Corpuscular (IFIC).