3.1. Introduction

There exist intricate geometric relations between multiple views of a 3D scene. These relations are related to the camera motion and calibration as well as to the scene structure. In this chapter, we introduce these concepts and discuss how they can be applied to recover 3D models from images.

In Section 3.2, a rather thorough description of projective geometry is given. Section 3.3 gives a short introduction to tensor calculus, and Section 3.4 describes in detail the camera model used. In Section 3.5, a modern approach to multiple view geometry is presented and in Section 3.6 simple structure and motion algorithms are presented. In Section 3.7, more advanced algorithms are presented that are suited for automatic processing on real image data. Section 3.8 discusses the possibility of calibrating the camera from images. Section 3.9 describes how the depth can be computed for most image pixels, and Section 3.10 presents how the results of the previous sections can be combined to yield 3D models, render novel views, or combine real and virtual elements in video.