The design of a special-purpose systolic image convolution processor for use in a robot vision system is described. It presents a high-speed two-dimensional hardware convolution architecture based on VSLI systolic arr...
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The design of a special-purpose systolic image convolution processor for use in a robot vision system is described. It presents a high-speed two-dimensional hardware convolution architecture based on VSLI systolic arrays for image processing applications. An architecture for the parallel processing of the generalized two-dimensional convolution is summarized. A VLSI convolution chip was designed to accommodate various convolution window sizes. The number of coefficients being handled is directly proportional to the number of systolic computing elements (processors) used. In the present design three such processors are configured on one VLSI chip. Signed coefficients and unsigned data of eight bits are supported. All processing and interprocessor communications are performed bit-serially. The chip design incorporates error detection during convolution, and overflow avoidance techniques are possible for maximum system autonomy. The chip is estimated to operate at a maximum frequency of 16 MHz.< >
A representation and a computational model for deriving three-dimensional articulated volumetric descriptions of objects from laser range-finder data are described. What differentiates this work from other approaches ...
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A representation and a computational model for deriving three-dimensional articulated volumetric descriptions of objects from laser range-finder data are described. What differentiates this work from other approaches is that it is purely bottom up, relying on general assumptions cast in terms of differential geometry. Darboux frames, snakes, and superquadrics form the basis of this representation, and curvature consistency provides the computational framework. The organization is hierarchical. Darboux frames are used to describe the local surface, while snakes are used to interpolate between features, particularly those that serve to partition a surface into its constituent parts. Superquadrics are subsequently used to characterize the 3-D shape of each surface partition. The result is a set of connected volumetric primitives which serve to describe the overall shape of an object. A set of examples showing how the approach performs on data acquired with a laser range finder is included.< >
A fast adaptive Hough transform (FAHT) approach is developed for detecting shapes which can be characterized by two parameters. This class of shapes includes both linear and circular image features. The method is base...
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A fast adaptive Hough transform (FAHT) approach is developed for detecting shapes which can be characterized by two parameters. This class of shapes includes both linear and circular image features. The method is based on identifying linear and circular segments in images by searching for clusters of evidence in two-dimensional parameter spaces. The FAHT differs from HT in the degree of freedom allowed in the placement and choice of shape of the window which defines the range of parameters under study at each resolution. This method is superior to that of HT implementation in both storage and computational requirements. The ideas of the FAHT are illustrated by tackling the problem of identifying linear segments in images by searching for clusters of evidence in two-dimensional parameter spaces. It is shown that the method is robust to the addition of extraneous noise and can be used to analyze complex images containing more than one shape.< >
A joint-trajectory-generation scheme for redundant robots is proposed which uses the redundancy to improve motion performance according to certain objective functions. The objective function can be either analytical o...
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A joint-trajectory-generation scheme for redundant robots is proposed which uses the redundancy to improve motion performance according to certain objective functions. The objective function can be either analytical or nonanalytical. For nonanalytical objective functions, a least-squares scheme is proposed to estimate the gradient vector. In addition, an approximation scheme is developed to compute the pseudoinverse of the Jacobian. Application of the scheme to a 4-link revolute planar robot manipulator is demonstrated through simulation. Several motion performance criteria are considered and their results analyzed.< >
The authors discuss the utility of a truth maintenance system (TMS) in action representation and plan modification. They present a way of representing actions and their effects in a TMS that is useful as a step toward...
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The authors discuss the utility of a truth maintenance system (TMS) in action representation and plan modification. They present a way of representing actions and their effects in a TMS that is useful as a step towards a planner using TMS dependency structures. An action is represented as a TMS node. Action preconditions are explicitly represented. The authors represent effects of actions by modifying justifications. A way to construct a partial temporal order of actions is suggested. They also give a partial solution to the culprit identification problem.< >
An approach to the problem of finding the minimum number of inertial parameters of the robot manipulator dynamic equations of motion is presented. Based on the energy difference equation, it is equally applicable to s...
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An approach to the problem of finding the minimum number of inertial parameters of the robot manipulator dynamic equations of motion is presented. Based on the energy difference equation, it is equally applicable to serial-link graph-structured manipulators. The authors prove that the minimum number of parameters can be obtained directly from an energy difference equation rather than the dynamic equations of motion. They present a method for the identification of the minimum number of basis vectors which span the vector space containing the components of inertial parameters present in the equations of motion. Simulations are presented and the method is evaluated. The method is conceptually simple, computationally efficient and easy to implement. In particular, the manipulator kinematics and the joint positions and velocities are the only inputs to the algorithm.< >
The problem of automatically generating the possible 3-D sensor locations for observing a scene is defined, and an approach to its solution is presented. The approach taken assumes that the sensor characteristics are ...
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The problem of automatically generating the possible 3-D sensor locations for observing a scene is defined, and an approach to its solution is presented. The approach taken assumes that the sensor characteristics are well understood and that objects expected in the scene are known and modeled. Then, given a set of constraints, a set of actions is specified directing a robot arm to position itself in such a manner that an attached 3-D sensor located in the robot gripper yields the maximum information content with minimum effort with respect to the constraints. Techniques that yield solutions for placement of a triangulation-type 3-D laser range finder are presented.< >
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