Author name cluster

Wolfgang Sepp

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7 papers

1 author row

IROS Conference 2011 Conference Paper

Particle filter based monocular human tracking with a 3D cardbox model and a novel deterministic resampling strategy

Ziyuan Liu
Dongheui Lee
Wolfgang Sepp

The challenge of markerless human motion tracking is the high dimensionality of the search space. Thus, efficient exploration in the search space is of great significance. In this paper, a motion capturing algorithm is proposed for upper body motion tracking. The proposed system tracks human motion based on monocular silhouette-matching, and it is built on the top of a hierarchical particle filter, within which a novel deterministic resampling strategy (DRS) is applied. The proposed system is evaluated quantitatively with the ground truth data measured by an inertial sensor system. In addition, we compare the DRS with the stratified resampling strategy (SRS). It is shown in experiments that DRS outperforms SRS with the same amount of particles. Moreover, a new 3D articulated human upper body model with the name 3D cardbox model is created and is proven to work successfully for motion tracking. Experiments show that the proposed system can robustly track upper body motion without self-occlusion. Motions towards the camera can also be well tracked.

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IROS Conference 2009 Conference Paper

On the issue of camera calibration with narrow angular field of view

Klaus H. Strobl
Wolfgang Sepp
Gerhard Hirzinger

This paper considers the issue of calibrating a camera with narrow angular field of view using standard, perspective methods in computer vision. In doing so, the significance of perspective distortion both for camera calibration and for pose estimation is revealed. Since narrow angular field of view cameras make it difficult to obtain rich images in terms of perspectivity, the accuracy of the calibration results is expectedly low. From this, we propose an alternative method that compensates for this loss by utilizing the pose readings of a robotic manipulator. It facilitates accurate pose estimation by nonlinear optimization, minimizing reprojection errors and errors in the manipulator transformations at the same time. Accurate pose estimation in turn enables accurate parametrization of a perspective camera.

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ICRA Conference 2009 Conference Paper

Rollin' Justin - Mobile platform with variable base

Christoph Borst 0001
Thomas Wimböck
Florian Schmidt 0001
Matthias Fuchs
Bernhard Brunner
Franziska Zacharias
Paolo Robuffo Giordano
Rainer Konietschke

Research on humanoid robots for use in servicing tasks, e. g. fetching and delivery, attracts steadily more interest. With “Rollin' Justin” a mobile robotic system and research platform is presented that allows sophisticated control algorithms and dexterous manipulation. This video gives an overview of the mobile humanoid robotic system “Rollin' Justin” with special emphasis on mechanical design features, control issues and high-level system capabilities such as human robot interaction.

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IROS Conference 2009 Conference Paper

The self-referenced DLR 3D-modeler

Klaus H. Strobl
Elmar Mair
Tim Bodenmüller
Simon Kielhöfer
Wolfgang Sepp
Michael Suppa
Darius Burschka
Gerhard Hirzinger

In the context of 3-D scene modeling, this work aims at the accurate estimation of the pose of a close-range 3-D modeling device, in real-time and passively from its own images. This novel development makes it possible to abandon using inconvenient, expensive external positioning systems. The approach comprises an ego-motion algorithm tracking natural, distinctive features, concurrently with customary 3-D modeling of the scene. The use of stereo vision, an inertial measurement unit, and robust cost functions for pose estimation further increases performance. Demonstrations and abundant video material validate the approach.

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IROS Conference 2007 Conference Paper

Tackling multi-sensory 3D data acquisition and fusion

Tim Bodenmüller
Wolfgang Sepp
Michael Suppa
Gerhard Hirzinger

The development of applications for multi-sensor data fusion typically faces heterogeneous hardware components, a variety of sensing principles and limited computational resources. We present a concept for synchronization and communication which tackles these challenges in multi-sensor systems in a unified manner. Here, a combination of hardware synchronization and deterministic software signals is promoted for global synchronization. Patterns of event-driven communication ensure that sensor data processing and evaluation are not bound to runtime constraints induced by data acquisition anymore. The combination of unified range and pose data description, event-driven communication, and global synchronization allows to build 3D sensing applications for various tasks. The proposed concept is implemented and evaluated for a variety of applications based on the DLR multisensory 3D-modeller. Extendability to other range and pose sensors is straightforward.

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IROS Conference 2006 Conference Paper

Hierarchical Featureless Tracking for Position-Based 6-DoF Visual Servoing

Wolfgang Sepp
Stefan Fuchs
Gerhard Hirzinger

Classical position-based visual servoing approaches rely on the presence of distinctive features in the image such as corners and edges. In this contribution we exploit a hierarchical approach for object detection, initial-pose estimation, and real-time tracking based first on colour distribution and subsequently on the shape and texture information. The shape model of the object is not limited to surface primitives but allow for any free-form surface not subject to self-occlusion. We evaluate the approach as part of a handshake scenario where a 7-DoF robot takes a free moving object over from a human

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ICRA Conference 2004 Conference Paper

The DLR Multisensory Hand-Guided Device: the Laser Stripe Profiler

Klaus H. Strobl
Wolfgang Sepp
Eric Wahl
Tim Bodenmüller
Michael Suppa
Javier F. Seara
Gerhard Hirzinger

This paper presents the DLR Laser Stripe Profiler as a component of the DLR multisensory Hand-Guided Device for 3D modeling. After modeling the reconstruction process, we propose a novel method for laser plane self-calibration based on the assessment of the deformations the miscalibration leads to. In addition, the requirement for absence of optical filtering implies the development of a robust stripe segmentation algorithm. Experiments demonstrate the validity and applicability of the approaches.

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