Structured-light 3D reconstruction and applications

Abstract

An increasing number of modern Computer Vision applications rely on the usage of depth data, allowing the accomplishment of several tasks otherwise being complex or impractical. As a consequence, a large amount of 3D acquisition methods have been proposed in literature, each one designed for a specific objective. In particular, structured-light approaches employ a projector to cast additional information over the scene to compute correspondences between two views and obtain a dense reconstruction. This thesis presents two main contributions in the field of 3D reconstruction: first, some improvements over a state-of-the-art structured light technique called fringe projection are presented. We start from a theoretical characterization of the acquired signal and formulate a novel phase unwrapping technique offering high resilience to noise and outliers. Additionally, we propose a code recovering technique and a phase correcting method to further improve the final reconstruction accuracy. The second main contribution involves some real-world applications exploiting 3D reconstruction techniques in heterogeneous fields. In particular, we present a cylinder extraction technique designed to work in industrial settings where non-oriented, noisy point clouds are acquired from the scene and a structured-light approach for micrometric surface reconstruction. Another application involves the employment of the described techniques in the field of cultural heritage, where the final outcome yields to a reverse engineering process in addiction to the main preservation purpose.