Browsing by Author "Stoeter, Sascha A."

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    Closed Dynamic Contours that Split and Merge
    (2003-02-05) Stoeter, Sascha A.
    Classical dynamic contours suffer from their inability to properly address the crossover problem. In the closed contour case, a part of the snake inverts and expands without bounds. This report proposes a novel approach to handle inversions by splitting the contour at the points of self-intersection. Separated parts that are inverted aredestroyed while the remaining parts are used to seed newsnakes. Collisions of snakes cause them to merge. The probability of crossovers is further reduced by an efficient reparameterization procedure. The method is successfully applied to track the globule in a motion lamp.
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    Performance of a Distributed Robotic System Using Shared Communications Channels
    (2001-07-26) Rybski, Paul E.; Stoeter, Sascha A.; Gini, Maria; Hougen, Dean
    We have designed and built a set of miniature robots, called Scouts. In addition, we have developed a distributed software system to control them. This paper addresses the fundamental choices we made in the design of the control software, describes experimental results in a surveillance task,and analyzes the factors that affect robot performance. Space and power limitations on the Scouts severely restrict the computational power of their on-board computer, which can only handle low-level control operations and data communication on an RF data link. We use a proxy-processing scheme, in which the robots are dependent on remote computers for their computing needs. While this allows the distributed robotics system to be autonomous, the fact that the robots behaviors are executed on remote computers introduces an additional complication -- the behavior controller has to receive sensor data and send commands to the robots using RF communication channels. Because the capacity of the communication system is limited, the robots must share bandwidth. We have developed a process management/scheduling system that is capable of handling high demand when controlling a group of robots. The resource allocation system dynamically assigns resources to each robot in an attempt to maximize the utilization of the available resources while still maintaining a priori behavior priorities. We present experimental results on a surveillance task in which multiple robots patrol an area and watch for motion. We discuss how the limited communication bandwidth affects robot performance in accomplishing the task and analyze how performance depends on the number of robots that share the bandwidth.
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    Visual Servoing of a Miniature Robot Toward a Marked Target
    (2002-01-31) Rößler, Patrick; Stoeter, Sascha A.; Rybski, Paul E.
    The paper describes a system that servos a miniature robot toward a marked target based on visual information from the robot's own camera. This task is divided into two subtasks: recognition of the target and driving toward the target while updating the estimation of its position. This system deals with the problems introduced by noisy camera images and unstructured non-static backgrounds. A description of the control software is given and experimental results arediscussed.