Search results for "Segno"
showing 10 items of 1358 documents
La ricostruzione da immagini con tecniche di restituzione prospettica
2018
Il contributo è incentrato sulla ricostruzione di opere di architettura perdute da fotografie attraverso l’uso di tecniche di restituzione prospettica. Una breve introduzione illustra le ragioni che relegano la restituzione prospettica a un ruolo secondario nel contesto delle ricostruzioni virtuali; il paragrafo successivo illustra i risultati di un test sul confronto fra restituzione prospettica da singolo fotogramma e restituzione SfM. Il paragrafo conclusivo descrive la ricostruzione virtuale di una chiesa di Palermo, demolita nella prima metà del XX secolo e documentata da poche foto d’epoca. The paper focuses the 3D reconstruction of buildings that were destroyed during the World War I…
A 3D reworking of the urban transformations of Palermo in recent history for a hypothesis of a "City Museum" based on digital visualizations
2021
The objective that drives this research is given by a multitude of information which, in addition to the contribution of technology, allows us to study, analyze, verify and remodel the sites, monuments and evolutions of the city through graphic processes of perspective restitution that start from the analysis of historical photos. The drawing methods, the digital graphic rendering and through the aid of geometric techniques, contribute to the reconstruction of projects and architectures that are now lost, this is possible thanks to the methods of perspective, axonometry and three-dimensional restitution. This remarkable photographic heritage belonging to Palermo, but also to any other city …
PERSPECTIVE RESTITUTION FROM VIEW CAMERAS PHOTOS
2022
Abstract. The paper aims at discussing the accuracy of perspective restitution from view camera photos; view cameras are non-standard cameras frequently used in the past century for on field shooting of buildings and urban sites; this is why the reconstruction of lost buildings often deals with photos taken with a view camera. The case study chosen for the proposed experiment is an urban complex built in Palermo in the ‘50s. The site features a very regular layout with surfaces at right angle, that supports the graphic reconstruction of photos’ inner and outer orientation. The site has been surveyed with a laser scanner; the point cloud provided the metric information needed for the evaluat…
Dalla Fotografia alla ricostruzione: Porta Maqueda a Palermo
2022
The reconstruction of gone, or never built buildings has ever been one of the preferred subjects of digital representation. Many researches have focused the reconstruction of buildings that were modified by human actions, as wars or demolitions, or by natural causes as earthquakes or decay. Many buildings, destroyed or reshaped from the second half of the 19th century have been photographed before they vanished; when no drawing or document are available, the memory of the architecture layout of these buildings is entrusted to few period photos. Digital representation makes the reconstruction of gone buildings from period photos possible. Descriptive Geometry provides the conceptual and oper…
Review of RGB photoelasticity
2015
Abstract Automatic methods of photoelasticity have had a significant progress with the development of automatic acquisition and image processing methods. This article concerns RGB photoelasticity, which allows the determination of the photoelastic retardation using, usually, a single acquisition of the isochromatic fringes in white light by a colour camera. In particular, the article presents an overview of the main characteristics of RGB photoelasticity that is influence of the quarter-wave plate error, number of acquisitions, type of light source, determination of low and high fringe orders, methods for searching the retardation, scanning procedures, calibration on a material different fr…
Phase shifting photoelasticity in white light
2007
The availability of image acquisition systems has led to the development of digital photoelasticity both in monochromatic and white light. In particular white light has been used mainly with the following methods: Spectral Content Analysis, RGB photoelasticity and phase shifting photoelasticity. Phase shifting photoelasticity in the colour domain has been used effectively for the determination of the isoclinic parameter in order to reduce the influence of the isochromatic fringes. The method has been also proposed for the determination of the isochromatic fringe order. This paper concerns the general characteristics of phase shifting photoelasticity in the colour domain. Special attention i…
RGB photoelasticity applied to the analysis of membrane residual stress in glass
2011
The measurement of residual stresses is of great relevance in the glass industry. The analysis of residual stress in glass is usually made by photoelastic methods because glass is a photoelastic material. This paper considers the determination of membrane residual stresses in glass plates by automatic digital photoelasticity in white light (RGB photoelasticity). The proposed method is applied to the analysis of membrane residual stresses in some tempered glass. The proposed method can effectively replace manual methods based on the use of white light, which are currently provided by some technical standards.
Photoelastic Analysis of Edge Residual Stresses in Glass by the Automated Tint Plate Method
2013
The analysis of residual stress in glass is usually carried out by means of photoelastic methods. This article considers the automation of the white light photoelastic method based on the use of a full-wave plate placed behind the glass plate. In particular, the method in based on the use of RGB photoelasticity in white light in conjunction with a full wave plate. The proposed method have been applied to the analysis of membrane residual stresses in tempered glass, showing that it can effectively replace manual methods of photoelastic analysis of residual stresses in glass when a low photoelastic retardation is present.
Un’esperienza di rilevamento architettonico con tecniche integrate
2004
Lo studio esposto riguarda la sperimentazione sulle tecniche per il rilevamento e la rappresentazione di manufatti architettonici caratterizzati dalla presenza di una ricca decorazione scultorea. In particolare, è stata condotta una applicazione sulla parete di ingresso dell’Oratorio del SS. Rosario presso la chiesa di Santa Cita, nel centro storico di Palermo. Nel corso dello studio sono stati messi a confronto ed integrati i dati provenienti dal rilevamento diretto, topografico, fotogrammetrico, e da acquisizioni eseguite con laser a scansione. This paper is addressed to test suitable techniques for surveying and restitution of architectural surfaces decorated with free-form masses (i.e. …
Monoscopic Photogrammetry to Investigate the Buildings in the Period of Modernism in Salerno: The Case Study of Torquato Tasso High School
2021
The city of Salerno and the expansion that underwent in the 1920s in order to respond to the urban expansion following the demographic increase that occurred at the beginning of the century will be the topics discussed in this paper. Transformations that created a face to the city that, in its forms, although not linked to the most advanced avant-garde, represent a testimony of the new characteristics of the “modern” city. Within this evolutionary process of the province of Salerno there is the 1928 project of two engineers, Michele and his son Luigi De Angelis for the construction of the “Regio” School. In a first moment, several projects found in the archives refer mainly to the various l…