An area of increasing interest in Al Robotics and computervision is integrating techniques from these fields to the problem of controlling autonomous systems. Space-based systems such as NASA''s robotic assem...
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ISBN:
(纸本)0819404543
An area of increasing interest in Al Robotics and computervision is integrating techniques from these fields to the problem of controlling autonomous systems. Space-based systems such as NASA''s robotic assembly of Orbital Replacement Units (ORU''s) provide a complex realistic domain for this integration research. In this paper we report on current MITRE research in the use of situated control for autonomous robotic assembly of ORUs. A wrist-mounted camera is used to acquire the pose of ORU''s. An on-line control module uses the pose data to refine the on-going robot actions so that the planned task can be executed both safely and robustly. Experimental results on a Cincinnati Milacron T3 Industrial robot at Goddard Space Right Center (GSFC) intelligent Robotic Laboratory will be included.
There is growing interest in using the complex logarithmic mapping for depth determination in motion stereo applications. This has lead to a need for a comprehensive error analysis. Rather than just giving an analytic...
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There is growing interest in using the complex logarithmic mapping for depth determination in motion stereo applications. This has lead to a need for a comprehensive error analysis. Rather than just giving an analytic description of the errors inherent in the approach, an attempt will be made to characterize the errors that occur when using the mapping with real images. techniques to reduce the impact of these errors will also be discussed.
This paper considers the control of two robotic manipulators jointly grasping-with no slippage-a rigid object. Two conflicting control problems are addressed: Adaptively apportioning the object load between the manipu...
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This paper considers the control of two robotic manipulators jointly grasping-with no slippage-a rigid object. Two conflicting control problems are addressed: Adaptively apportioning the object load between the manipulators and application of commanded interactive forces (or bias forces) to the object. By controlling the interactive forces, damage to the manipulators and/or the object can be prevented. Additionally, desired tension, torsion, or compression can be applied to the object. Adaptive load apportioning (sharing) increases the carrying capacity of the system by using possible mechanical advantage. The Hopfield net is used to minimize a quadratic energy function in the joint torques. The results are the optimal joint torques required to drive the load and supply the commanded bias force. Simulations are presented that show effective control of interactive forces while sharing the load in an optimal fashion.
Arranging the photosensitive elements of an imaging sensor in a log-polar grid automatically samples an image in a log-polar space. The Retina project is a chip with such a spatially varying layout that can produce th...
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Arranging the photosensitive elements of an imaging sensor in a log-polar grid automatically samples an image in a log-polar space. The Retina project is a chip with such a spatially varying layout that can produce the advantages of image processing in the new space at real-time speeds. The actual chip is a small part of a complete imaging system. The system is part of a class of imagers called foveal sensors, and these sensors have distinct and significant computational savings over conventional imagers, as many as 3-10 orders of magnitude improvement in processing time and memory. The design maintains a large region of high-resolution data, although it is still only a fraction of the total photosensitive area.
We explore the idea that the visual system uses specialized processes to extract critical information about 3-D motion and structure for visually-guided navigation. We first consider the computation of three essential...
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We explore the idea that the visual system uses specialized processes to extract critical information about 3-D motion and structure for visually-guided navigation. We first consider the computation of three essential properties: the relative 3-D direction of heading of the observer, the time-to-collision with approaching object surfaces, and the locations of object boundaries defined by motion discontinuities. We then focus on the heading computation, relating current algorithms to the perception of heading direction.
A recognition system, which represents object categories by properties which can be deduced by analysis of 3-D shape, has been implemented and tested using the category 'chair' for case study. Functional descr...
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A recognition system, which represents object categories by properties which can be deduced by analysis of 3-D shape, has been implemented and tested using the category 'chair' for case study. Functional description is used to recognize classes and identify subclasses of known categories of objects, even if the specific object has never been encountered previously. Interpretation of the functionality of an object is accomplished through qualitative reasoning about its shape. This is, to our knowledge, the first implemented system to explore the use of purely function-based representation (that is, no geometric or structural object model) to recognize 3-D objects. During the recognition process, evidence is gathered as to how well the functional requirements are met by the input structure. This paper is concerned with choosing the type of operators that will be used in the combination or accrual of the functional evidence. Three pairs of conjunctive and disjunctive operators are evaluated. Each pair is used in the recognition process of the 100 + test objects. The results of all tests run are compared and differences are discussed.
We investigate the use of chromatic information in dense stereo correspondence. Specifically, the chromatic photometric constraint, which is used to specify a mathematical optimality criterion for solving the dense st...
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We investigate the use of chromatic information in dense stereo correspondence. Specifically, the chromatic photometric constraint, which is used to specify a mathematical optimality criterion for solving the dense stereo correspondence problem, is developed. The result is a theoretical construction for developing dense stereo correspondence algorithms which use chromatic information. The efficacy of using chromatic information via this construction is tested by implementing single-and multi-resolution versions of a stereo correspondence algorithm which uses simulated annealing as a means of solving the optimization problem. Results demonstrate that the use of chromatic information can significantly improve the performance of dense stereo correspondence.
There is a growing need for progress in the technology for the management of knowledge derived from sensory data. In this paper we address the structure and operations of a cellular 'Experiential Knowledge Base - ...
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There is a growing need for progress in the technology for the management of knowledge derived from sensory data. In this paper we address the structure and operations of a cellular 'Experiential Knowledge Base - E*KB' system, which acts as a cognitive prosthesis to the decision maker. We concern ourselves with the experiential knowledge representation techniques, and with the methods and tools required for the extraction (relevance filtering), the contextual abstraction (data compression and generalization), the classification and storage of real time sensory knowledge in the cellular architecture of the E*KB.
Range images incorporate 3-D surface coordinates of a scene and are well suited for a variety of vision applications. For tasks, such as 3-D object recognition, a representation of the object(s) present in the image i...
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Range images incorporate 3-D surface coordinates of a scene and are well suited for a variety of vision applications. For tasks, such as 3-D object recognition, a representation of the object(s) present in the image is derived and then matched with stored models to determine the object(s) identity. Surface based representation is the most widely used representation in range image analysis. To generate surface based representation of an object, a segmentation of the object into a number of surfaces is needed. In this paper we present an approach for the segmentation of range images into a number of surfaces that, in turn, can be used to generate surface based representation. The approach integrates both edge detection and region growing techniques to achieve the segmentation. We start by detecting jump edges. Jump edge map is processed and regions surrounded by jump edges are isolated. Next, fold edges are detected iteratively using normals and residual. Fold edge map is processed to obtain the final segmented image. Jump and fold edge maps are processed using a Bayesian approach. The apriori knowledge is modeled using Markov Random Field. For jump edges we have used a coupled line and depth process. For fold edges we have combined line, residuals and normals to process the fold edge map. The performance of the algorithm on a number of range images is presented.
algorithms for robotic real-time visual tracking of arbitrary 3-D objects traveling at unknown velocities in a 2-D space are presented. The problem of visual tracking is formulated as a problem of combining control wi...
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ISBN:
(纸本)081862163X
algorithms for robotic real-time visual tracking of arbitrary 3-D objects traveling at unknown velocities in a 2-D space are presented. The problem of visual tracking is formulated as a problem of combining control with computervision. A mathematical formulation that is general enough to be extended to the problem of tracking 3-D objects in 3-D space is presented. The authors propose the use of sum-of-squared differences (SSD) optical flow for the computation of the vector of discrete displacements each instant of time. These displacements can be fed either directly to a PI controller, a pole assignment controller, or a discrete steady-state Kalman filter. In the latter case, the Kalman filter calculates the estimated values of the system's states and exogenous disturbances, and a discrete LQG controller computes the desired motion of the robotic system. The outputs of the controllers are sent to a Cartesian robotic controller that drives the robot.
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