The condition that allows the principles of projection to be applied to photography comes from the identity relationship between photographic images and central projection. In fact, the process of forming central projection can be seen in the ideal bundle of projection rays, with their centre in the objective lens, which hit the points of the object and fix the relative image in the photographic plane. According to this identity relationship, the centre of the objective lens is the point of view of central projection; the photographic image plane is the perspective plane on which the image forms; and the focus of the objective lens is the principal distance. If each photo is considered as a perspective, it is possible to render the geometric configuration of the subject photographed if the elements defining the perspective system—i.e., the principal point, the horizon, and the distance circle—are known or can be defined. It is also possible to obtain measurements (and not just proportions) if the photography conditions or at least one real measurement relative to either the subject is known.
Published in Chapter:
Digital Photogrammetry and Structure from Motion for Architectural Heritage: Comparison and Integration between Procedures
Elena Ippoliti (Sapienza University of Rome, Italy), Alessandra Meschini (University of Camerino, Italy), and Filippo Sicuranza (Sapienza University of Rome, Italy)
Copyright: © 2015
|Pages: 58
DOI: 10.4018/978-1-4666-8379-2.ch004
Abstract
The goal of this paper is to focus on multi-image monoscopic digital photogrammetry, illustrating several types of applications used in a single case study chosen for its unique characteristics: Palazzo dei Capitani del Popolo in the main square in the old town centre of Ascoli Piceno. The description of this experimentation will be illustrated in the paper not only to assess the potential and limits of these systems, but also to place them in a scientific context and recall the theoretical fundamentals of this method, since we believe these in-depth studies to be increasingly necessary in order for these digital technologies to be used properly.