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

Measuring BRDFs of Immersed Materials

Kai Berger, Ilya Reshetouski, Marcus Magnor, Ivo Ihrke
In: Proceedings of VMV 2011.



Abstract

We investigate the effect of immersing real-world materials into media of different refractive indices. We show, that only some materials follow the Fresnel-governed behaviour. In reality, many materials exhibit unexpected effects such as stronger localized highlights or a significant increase in the glossy reflection due to microgeometry. In this paper, we propose a new measurement technique that allows for measuring the BRDFs of materials that are immersed into different media.

Bibtex

@InProceedings{Berger11,
author = {Kai Berger and Ilya Reshetouski and Marcus A. Magnor and Ivo Ihrke},
title = "{Measuring BRDFs of Immersed Materials}",
booktitle = {Proceedings of VMV},
pages = "325--330",
year = {2011},
}
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