3D Shape Analysis

33D Acquisition and Preprocessing

3.1 Introduction

Before we can elaborate in detail on 3D shape analysis techniques, we need to understand the process that underpins the creation of 3D models. This is often referred to as 3D reconstruction. It involves the acquisition of 3D data followed by preprocessing steps, which clean, smooth, and optimize the 3D data to facilitate their analysis and usage in various applications. In this chapter, we will review in Section 3.2 the existing 3D acquisition techniques and systems. We will particularly discuss the different characteristics that can influence decision making when it comes to selecting a system or a technique that would best suit a given application.

In general, 3D acquisition systems produce raw 3D data that are not necessarily clean and in a representation that does not suit shape analysis tasks. Section 3.3 introduces some of the basic techniques used for smoothing, cleaning, and repairing 3D data. It also discusses parameterization techniques, which convert discrete representations of 3D shapes into a continuous one.

The material covered in this chapter is a brief summary of a very rich and deep set of topics, traditionally covered in a number of separate books. A more thorough introduction to 3D reconstruction techniques can be found in textbooks on multiview geometry 23. Preprocessing techniques are usually covered in textbooks on 3D geometry processing such as 1.

3.2 3D Acquisition

The goal of the 3D acquisition task ...