Browsing by Author "WANG, LL"

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CAMERA CALIBRATION BY VANISHING LINES FOR 3-D COMPUTER VISION
(1991-04-01)
WANG, LL
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TSAI, WH
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資訊科學與工程研究所
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Institute of Computer Science and Engineering
A new approach to camera calibration by vanishing lines is proposed. Calibrated parameters include the orientation, the position, and the focal length of a camera. A hexagon is employed as the calibration target to generate a vanishing line of the ground plane from its projected image. It is shown that the vanishing line includes useful geometric hints about the camera orientation parameters and the focal length, from which the orientation parameters can be solved easily and analytically. And the camera position parameters can be calibrated by the use of related geometric projective relationships. The simplicity of the target eliminates the complexity of the environment setup and simplifies the feature extraction in relevant image processing. The calibration formulas are also simple to compute. Experimental results show the feasibility of the proposed approach.
COLLISION AVOIDANCE BY A MODIFIED LEAST-MEAN-SQUARE-ERROR CLASSIFICATION SCHEME FOR INDOOR AUTONOMOUS LAND VEHICLE NAVIGATION
(1991-10-01)
WANG, LL
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TSAI, WH
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資訊工程學系
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Department of Computer Science
In this article, a new collision-avoidance scheme is proposed for autonomous land vehicle (ALV) navigation in indoor corridors. The goal is to conduct indoor collision-free navigation of a three-wheel ALV among static obstacles with no a priori position information as well as moving obstacles with unknown trajectories. Based on the predicted positions of obstacles, a local collision-free path is computed by the use of a modified version of the least-mean-square-error (LMSE) classifier in pattern recognition. Wall and obstacle boundaries are sampled as a set of 2D coordinates, which are then viewed as feature points. Different weights are assigned to different feature points according to the distances of the feature points to the ALV location to reflect the locality of path planning. The trajectory of each obstacle is predicted by a real-time LMSE estimation method. And the maneuvering board technique used for nautical navigation is employed to determine the speed of the ALV for each navigation cycle. Smooth collision-free paths found in the simulation results are presented to show the feasibility of the proposed approach.
COLLISION-AVOIDANCE BY FUZZY-LOGIC CONTROL FOR AUTOMATED GUIDED VEHICLE NAVIGATION
(1994-12-01)
LEE, PS
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WANG, LL
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資訊工程學系
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Department of Computer Science
A fuzzy approach to collision avoidance for automated guided vehicle (AGV) navigation is proposed. Static obstacles with no a priori position information as well as moving obstacles with unknown trajectories are considered in this study. Intuitive and subjective human ideas of collision avoidance are modeled into fuzzy rules. Fuzzy logic is applied in the inference procedure for AGV navigation, such that the AGV is guided from the starting point toward the target without colliding with obstacles. Furthermore, the proposed method can also be used for the navigation of multiple AGVs, where each AGV must avoid other AGVs as well as obstacles in the environment. Simulation results are presented to show the feasibility of the proposed fuzzy. approach. (C) 1994 John Wiley & Sons, Inc.
OPTIMAL ASSIGNMENT OF TASK MODULES WITH PRECEDENCE FOR DISTRIBUTED-PROCESSING BY GRAPH MATCHING AND STATE-SPACE SEARCH
(1988)
WANG, LL
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TSAI, WH
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資訊工程學系
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Department of Computer Science