Generalized Image Acquisition and Analysis

A Kaleidoscopic Approach to Surround Geometry and Reflectance Acquisition

We describe a system for acquiring reflectance fields of objects without moving parts and without a massively parallel hardware setup. Our system consists of a set of planar mirrors which serve to multiply a single camera and a single projector into a multitude of virtual counterparts. Using this arrangement, we can acquire reflectance fields with an average angular sampling rate of about 120+ view/light pairs per surface point. The mirror system allows for freely programmable illumination with full directional coverage. We employ this setup to realize a 3D acquisition system that employs structured illumination to capture the unknown object geometry, in addition to dense reflectance sampling. On the software side, we combine state-of-the-art 3D reconstruction algorithms with a reflectance sharing technique based on non-negative matrix factorization in order to reconstruct a joint model of geometry and reflectance. We demonstrate for a number of test scenes that the kaleidoscopic approach can acquire complex reflectance properties faithfully. The main limitation is that the multiplexing approach limits the attainable spatial resolution, trading it off for improved directional coverage.

Projects

A Mathematical Model and Calibration Procedure for Galvanometric Laser Scanning Systems

Alkhazur Manakov, Hans-Peter Seidel, Ivo Ihrke
In: Vision, Modeling, and Visualization (VMV 2011)



Abstract

Laser galvanometric scanning systems are commonly used in various fields such as three dimensional scanning, medical imaging, material processing, measurement devices and laser display systems. The systems of such kind suffer from distortions. On top of that they do not have a center of projection, which makes it impossible to use common projector calibration procedures. The paper presents a novel mathematical model to predict the image distortions caused by galvanometric mirror scanning systems. In addition, we describe a calibration procedure for recovering its intrinsic and extrinsic parameters.

Bibtex

@InProceedings{Manakov11,
author = {Alkhazur Manakov and Hans-Peter Seidel and Ivo Ihrke},
title = "{A Mathematical Model and Calibration Procedure for Galvanometric Laser Scanning Systems}",
booktitle = {Proceedings of VMV},
pages = "207--214",
year = {2011},
}
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