Mirrors in Computer Graphics, Computer Vision and Time-of-Flight Imaging

Abstract

Mirroring is one of the fundamental light/surface interactions occurring in the real world. Surfaces often cause specular reflection, making it necessary to design robust geometry recovery algorithms for many practical situations. In these applications the specular nature of the surface is a challenge. On the other side, mirrors, with their unique reflective properties, can be used to improve our sensing modalities, enabling applications such as surround, stereo and light field imaging. In these scenarios the specular interactions are highly desirable. Both of these aspects, the utilization and circumvention of mirrors are present in a significant amount of publications in different scientific areas. These publications are covering a large number of different problem statements as well as many different approaches to solutions. In the chapter we will focus on a collection and classification of the work in this area.

Use of High-Quality and Common Commercial Mirrors for Scanning Close-Range Surfaces Using 3D Laser Scanners: A Laboratory Experiment

“…Due to the specular reflection, the law of reflection states that the obtained image is symmetrical to the original. Due to this, a transformation is required [28] in order to enable the comparison of the different point clouds. As it is a planar transformation, it is addressed by changing the sign of one coordinates; in our particular case the coordinate changed was x.…”

A Linear Extrinsic Calibration of Kaleidoscopic Imaging System from Single 3D Point

“…In the context of kaleidoscopic imaging, Ihrke et al [10] and Reshetouski and Ihrke [19,20] have proposed a theory on modeling the chamber detection, segmentation, bounce tracing, shape-from-silhouette, etc. In these studies, however, the geometric calibration of the mirrors is simply achieved by detecting chessboards first [29], and then by estimating the mirror normals and the distances from chessboard 3D positions in the camera frame.…”

“…While their original motivation is to estimate the 3D structure from its indirect views via mirrors, they can be used for calibrating the kaleidoscopic system by supposing the direct view were not available. For example, the orthogonality constraint on mirrored 3D points proposed by [27] can be considered as another approach for kaleidoscopic system calibration in [10,20].…”

3D Structured Light Scanner on the Smartphone

“…Interestingly, Samsung (including other manufactures as well) have not considered the use of a cameraprojector pair for SL scanning, since apparently smartphone's camera and pico projector typically do not share a common field of view (FOV). To redirect light rays, complex configurations of mirrors have been extensively used in all kinds of imaging systems [13]. As an additional contribution we propose the use of a simple adapter with a first surface mirror which, as will be shown, neatly resolves the FOV issue.…”