Generalized Image Acquisition and Analysis

Discovering the Structure of a Planar Mirror System from Multiple Observations of a Single Point

We investigate the problem of identifying the position of a viewer inside a room of planar mirrors with unknown geometry in conjunction with the room’s shape parameters. We consider the observations to consist of angularly resolved depth measurements of a single scene point that is being observed via many multi-bounce interactions with the specular room geometry. Applications of this problem statement include areas such as calibration, acoustic echo cancelation and time-of-flight imaging. We theoretically analyze the problem and derive sufficient conditions for a combination of convex room geometry, observer, and scene point to be reconstructable. The resulting constructive algorithm is exponential in nature and, therefore, not directly applicable to practical scenarios. To counter the situation, we propose theoretically devised geo- metric constraints that enable an efficient pruning of the solution space and develop a heuristic randomized search algorithm that uses these constraints to obtain an effective solution. We demon- strate the effectiveness of our algorithm on extensive simulations as well as in a challenging real-world calibration scenario.


Interactive Geometry-Aware Segmentation for the Decomposition of Kaleidoscopic Images

Oliver Klehm, Ilya Reshetouski, Elmar Eisemann, Hans-Peter Seidel, Ivo Ihrke
VMV 2012


Mirror systems have recently emerged as an alternative low-cost multi-view imaging solution. The use of these systems critically depends on the ability to compute the background of a multiply mirrored object. The images taken in such systems show a fractured, patterned view, making edge-guided segmentation difficult. Further, global illumination and light attenuation due to the mirrors make standard segmentation techniques fail. We therefore propose a system that allows a user to do the segmentation manually. We provide convenient tools that enable an interactive segmentation of kaleidoscopic images containing three-dimensional objects. Hereby, we explore suitable interaction and visualization schemes to guide the user. To achieve interactivity, we employ the GPU in all stages of the application, such as 2D/3D rendering as well as segmentation.
Video Demo Data Set


author = {Oliver Klehm, Ilya Reshetouski, Elmar Eisemann, Hans-Peter Seidel, and Ivo Ihrke},
title = "{Interactive Geometry-Aware Segmentation for the Decomposition of Kaleidoscopic Images }",
booktitle = {Proceedings of VMV},
pages = "xx--yy",
year = {2012},
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