Generalized Image Acquisition and Analysis

From Capture to Simulation - Connecting Forward and Inverse Problems in Fluids

We explore the connection between fluid capture, simulation and proximal methods, a class of algorithms commonly used for inverse problems in image processing and computer vision. Our key finding is that the proximal operator constraining fluid velocities to be divergence-free is directly equivalent to the pressure-projection methods commonly used in incompressible flow solvers. This observation lets us treat the inverse problem of fluid tracking as a constrained flow problem all while working in an efficient, modular framework. In addition it lets us tightly couple fluid simulation into flow tracking, providing a global prior that significantly increases tracking accuracy and temporal coherence as compared to previous techniques. We demonstrate how we can use these improved results for a variety of applications, such as re-simulation, detail enhancement, and domain modification. We furthermore give an outlook of the applications beyond fluid tracking that our proximal operator framework could enable by exploring the connection of deblurring and fluid guiding.


Measuring BRDFs of Immersed Materials

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


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.


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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