As is known, human vision is capable of perceiving differences in distances to points in space. That is, human vision can perceive relief—it is stereoscopic. In fact, in seeing two different points, observers cannot evaluate the real distances between themselves and the points; rather, they perceive the difference between the two distances, i.e., they can assess which of two points is closer and which is further away. The physiological process of vision is very complex, but for our purposes it is important to recall that the perception of each individual point is realised by forming two separate retinal images, one in each eye. Using the principles of natural binocular vision, it is therefore possible to artificially reproduce stereoscopic vision. When simultaneously observing two photographic images of the same subject taken from two different points of view, instead of perceiving two distinct images, the observer sees a three-dimensional image of the subject. However, the appropriate optical tricks are necessary. In particular, the right-hand image should be seen only by the right eye and the left image only by the left eye. Under these conditions, two different retinal images are formed and sent simultaneously to the brain, which processes them and combines them to form a single virtual three-dimensional model. In theory, it is possible that whatever the photography conditions are, the two images always constitute a virtual three-dimensional model. While this is true of geometrical projection, to produce the effect in reality, the images should be made by simulating the conditions of natural binocular vision, thus taking into account the parameters of the inter-pupil distance and the object distance, with the associated reciprocal variations.
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.