ETH Zurich - D-INFK - IVC - CVG - Research

Research


Localization Localization | 3D Reconstruction | Optimization Methods | Motion Analysis | Micro Areal Vehicles

Visual Image Localization in Mountainous Areas

We address the problem of localizing any given photograph (of a mountainous landscape) using vision techniques only. We propose an automated approach for very large scale visual localization that can efficiently exploit visual information and geometric constraints at the same time. We validate the system on the scale of a whole country (Switzerland, 40'000 km²) using a new dataset of more than 200 landscape query pictures with ground truth.

Urban Location Recognition on Mobile Device

We address the problem of large scale place-of-interest recognition in cell phone images of urban scenarios. Here, we go beyond what has been shown in earlier approaches by exploiting the nowadays often available 3D building information (e.g. from extruded floor plans) and massive street-view like image data for database creation.

3D Reconstruction Localization | 3D Reconstruction | Optimization Methods | Motion Analysis | Micro Areal Vehicles

Distortion in Multiple View Geometry

Multiple view geometry is well-understood for the case of ideal pinhole cameras and many algorithms exist to estimate epipolar geometry, trifocal tensors or homographies. In this research we focus on the problem of multiple view relations between images with radial distortion. One important case is e.g. in sequential approaches where one registers an unknown image (potentially with radial distortion) to a set of previously calibrated images. Here, we introduce the single-sided radial fundamental matrix as well as algorithms for estimating and decomposing it.

Dense Reconstruction from Symmetry

A system is presented that takes a single image as an input (e.g. showing the interior of St.Peter's Basilica) and automatically detects an arbitrarily oriented symmetry plane in 3D space. Given this symmetry plane a second camera is hallucinated that serves as a virtual second image for dense 3D reconstruction, where the point of view for reconstruction can be chosen on the symmetry plane. This naturally creates a symmetry in the matching costs for dense stereo. Alternatively, we also show how to enforce the 3D symmetry in dense depth estimation for the original image. The two representations are qualitatively compared on several real world images, that also validate our fully automatic approach for dense single image reconstruction.

Discovering and Exploiting 3D Symmetries in Structure from Motion

We propose a new approach for structure from motion, where symmetry relations in the 3D structure are automatically recovered from multiple images and then imposed within a new constrained bundle adjustment formulation that incorporates robust priors on the expected model shape. Our approach significantly reduces drift through "structural" loop closures and improves the accuracy of reconstructions in urban scenes. We also use the discovered symmetries to estimate a natural coordinate system and complete the 3D model.

Optimization Methods Localization | 3D Reconstruction | Optimization Methods | Motion Analysis | Micro Areal Vehicles

Tight Convex Labeling

In this work we present a unified view on Markov random fields and recently proposed continuous tight convex relaxations for multi-label assignment in the image plane. These relaxations are far less biased towards the grid geometry than Markov random fields. It turns out that the continuous methods are non-linear extensions of the local polytope MRF relaxation. In view of this result a better understanding of these tight convex relaxations in the discrete setting is obtained. Further, a wider range of optimization methods is now applicable to find a minimizer of the tight formulation. We propose two methods to improve the efficiency of minimization. One uses a weaker, but more efficient continuously inspired approach as initialization and gradually refines the energy where it is necessary. The other one reformulates the dual energy enabling smooth approximations to be used for efficient optimization. We demonstrate the utility of our proposed minimization schemes in numerical experiments.

Motion Analysis Localization | 3D Reconstruction | Optimization Methods | Motion Analysis | Micro Areal Vehicles

Unstructured VBR

We present an algorithm designed for navigating around a performance that was filmed as a "casual" multi-view video collection: real-world footage captured on hand held cameras by a few audience members. The objective is to easily navigate in 3D, generating a video-based rendering (VBR) of a performance filmed with widely separated cameras. Casually filmed events are especially challenging because they yield footage with complicated backgrounds and camera motion. Such challenging conditions preclude the use of most algorithms that depend on correlation-based stereo or 3D shape-from-silhouettes.

Marker-less Motion Capture of Interacting People

The project aims to infer the poses of a character acting in a environment filmed by a set of video cameras. Once his poses are estimated, a free-viewpoint video of the entire action can be genertated.

Micro Areal Vehicles Localization | 3D Reconstruction | Optimization Methods | Motion Analysis | Micro Areal Vehicles

Vision Controlled MAV

This is a multi-year, student-driven project to create autonomous flying systems using pure onboard processing. We are focused on computer vision on Micro Air Vehicles, which allowed us to win the EMAV 2009 Indoor Autonomy Competition.

sFly: Swarm of Micro Flying Robots!

The obective of the sFly project is to develop several small and safe helicopters which can fly autonomously in city-like enviroments and which can be used to assist humans in tasks like rescue and monitoring.


© CVG, ETH Zürich lm@inf.ethz.ch