Peter Protzel

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Current SLAM back-ends are based on least squares optimization and thus are not robust against outliers like data association errors and false positive loop closure detections. Our paper presents and evaluates a robust back-end formulation for SLAM using switchable constraints. Instead of proposing yet another appearance-based data association technique,(More)
The ability to recognize known places is an essential competence of any intelligent system that operates autonomously over longer periods of time. Approaches that rely on the visual appearance of distinct scenes have recently been developed and applied to large scale SLAM scenarios. FAB-Map is maybe the most successful of these systems. Our paper proposes(More)
Superpixel segmentation showed to be a useful preprocessing step in many computer vision applications. This led to a variety of algorithms to compute superpixel segmentations, each with individual strengths and weaknesses. We discuss the need for a standardized evaluation scheme of such algorithms and propose a benchmark including data sets, error metrics,(More)
Current state of the art solutions of the SLAM problem are based on efficient sparse optimization techniques and represent the problem as probabilistic constraint graphs. For example in pose graphs the nodes represent poses and the edges between them express spatial information (e.g. obtained from odometry) and information on loop closures. The task of(More)
When operating over extended periods of time, an autonomous system will inevitably be faced with severe changes in the appearance of its environment. Coping with such changes is more and more in the focus of current robotics research. In this paper, we foster the development of robust place recognition algorithms in changing environments by describing a new(More)
We describe our work on multirotor UAVs and focus on our method for autonomous landing and position control. The paper describes the design of our landing pad and the vision based detection algorithm that estimates the 3D-position of the UAV relative to the landing pad. A cascaded controller structure stabilizes velocity and position in the absence of GPS(More)
Detecting, identifying, and recognizing salient regions or feature points in images is a very important and fundamental problem to the computer vision and robotics community. Tasks like landmark detection and visual odometry, but also object recognition benefit from stable and repeatable salient features that are invariant to a variety of effects like(More)
SLAM algorithms that can infer a correct map despite the presence of outliers have recently attracted increasing attention. In the context of SLAM, outlier constraints are typically caused by a failed place recognition due to perceptional aliasing. If not handled correctly, they can have catastrophic effects on the inferred map. Since robust robotic mapping(More)
Changing environments pose a serious problem to current robotic systems aiming at long term operation. While place recognition systems perform reasonably well in static or low-dynamic environments, severe appearance changes that occur between day and night, between different seasons or different local weather conditions remain a challenge. In this paper we(More)