• The Journal of the Acoustical Society of Korea
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• v.16 no.5
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• pp.26-35
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• 1997

This paper deals with establishing correspondent points of feature pints and sampling period when we estimate object motion parameters from image information of freely moving objects in space of gravity-free state. Replacing the inertial coordinate system with the camera coordinate system which is equipped within a space robot, it is investigated to be able to analyze a problem of correspond points from image information, and to obtain sequence of angular velocity $\omega$ which determine a motion of object by means of computer simulation. And if a sampling period ${\Delta}t$ is shortened, the relative errors of angular velocity are increased because the relative errors against moving distance of feature points are increased by quantization. In reverse, if a sampling period ${\Delta}t$ is lengthened too much, the relative error are likewise increased because a sampling period is long for angular velocity to be approximated, and we confirmed the precision that grows according to ascending of resolution.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.11
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• pp.995-1004
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• 2011

Object X-ray method commonly used for hole search in overset grids requires huge amount of time due to complicated vector calculations to search the cross-points as well as time-consuming hole search algorithm with respect to background grids. Especially, when the grid system is in motion relative to the background, hole points should be searched at every time step, leading to hung computational burden. To cope with this difficulties, this study presents an efficient hole search algorithm mainly designed to reduce hole searching time. To this end, virtual surface with reduced grid points is suggested and logical operators are employed as a classification algorithm instead of complicated vector calculations. In addition, the searching process is further accelerated by designating hole points in a row rather than discriminating hole points with respect to each background grid points. If there exists a relative motion, the present algorithm requires much less time because only the virtual surface needs to be moved at every time step. The hole searching time has been systematically compared for a few selected geometries.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.7
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• pp.1340-1345
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• 2001

In this paper, we proposed the method computing the optimal solution of Optical Flow(OF) representing the moving information of moving object and improving the operating speed. In order to do that, we computed the optimal solution of OF using the Combinatorial Hough Transform(CHT) and Voting accumulation and simply searched the moving object compared to conventional method.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.925-926
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• 2008

This paper presents an object tracking method using motion vectors generated in the MPEG4 encoding process and the snake algorithm for active contours. This paper shows the possibility of realtime object tracking during MPEG4 encoding process in a conventional surveillance system. The experiments is performed on a PC platform to prove the effectiveness of the method.

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.1091-1094
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• 1999

In this paper, we propose new algorithms to construct video object planes(VOP’s) for MPEG-4. VOP’s allow the new video standard MPEG-4 to enable content-based funtionalities. A comprehensive review summarizes some of the most important VOP’s generation techniques that have been proposed. The proposed algorithm use segmentation technique as labeling and motion estimation as three-step search algorithm(TSS). It is improved by a labeling technique that distinguishes background and object from a frame.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.57-57
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• 2000

The purpose of this paper is show that an chip mounter can be modeled by stochastic petri nets, and that the simulator to verify a fitness of the program to assemble. The chip mounter can be constructed by using the petri net class (CPetriNet) based on the object-oriented programming. By using this simulator, we can get the information about the description of motion of the chip mounter, and moreover, we can evaluate the productivity.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.2033-2036
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• 2004

A novel approach to estimate the real time moving trajectory of an object is proposed in this paper. The object position is obtained from the image data of a CCD camera, while a state estimator predicts the linear and angular velocities of the moving object. To overcome the uncertainties and noises residing in the input data, a Kalman filter and neural networks are utilized. Since the Kalman filter needs to approximate a non-linear system into a linear model to estimate the states, there always exist errors as well as uncertainties again. To resolve this problem, the neural networks are adopted in this approach, which have high adaptability with the memory of the input-output relationship. Kohonen Network(Self-Organized Map) is selected to learn the motion trajectory since it is spatially oriented. The superiority of the proposed algorithm is demonstrated through the real experiments.

• Proceedings of the IEEK Conference
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• 2001.06d
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• pp.89-92
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• 2001

In this paper, we propose a new approach for tracking a moving object in moving image sequences using active contour models and optical flow. In our approach object segmentation is achieved by active contours, and object tracking is done by motion estimation based on optical flow. To get more dynamic characteristics, Lagrangian dynamics combined to the active contour models. For the optical flow computation, a method, which is based on Spatiotempo-ral Energy Models, is employed to perform robust tracking under poor environments. A prototype real tracking system has been developed and applied to a contents-based video retrieval systems.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.302-305
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• 1996

This paper presents a visual servoing combined by Neural Network with optimal structure and predictive control for robotic manipulators to tracking or grasping of the moving object. Using the four feature image information from CCD camera attached to end-effector of RV-M2 robot manipulator having 5 dof, we want to predict the updated position of the object. The Kalman filter is used to estimate the motion parameters, namely the state vector of the moving object in successive image frames, and using the multi layer feedforward neural network that permits the connection of other layers, evolutionary programming(EP) that search the structure and weight of the neural network, and evolution strategies(ES) which training the weight of neuron, we optimized the net structure of control scheme. The validity and effectiveness of the proposed control scheme and predictive control of moving object will be verified by computer simulation.

• Journal of Mechanical Science and Technology
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• v.17 no.12
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• pp.1876-1885
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• 2003

The artificial potential field (APF) methods provide simple and efficient motion planners for practical purposes. However, these methods have a local minimum problem, which can trap an object before reaching its goal. The local minimum problem is sometimes inevitable when an object moves in unknown environments, because the object cannot predict local minima before it detects obstacles forming the local minima. The avoidance of local minima has been an active research topic in the potential field based path planing. In this study, we propose a new concept using a virtual obstacle to escape local minima that occur in local path planning. A virtual obstacle is located around local minima to repel an object from local minima. We also propose the discrete modeling method for the modeling of arbitrary shaped objects used in this approach. This modeling method is adaptable for real-time path planning because it is reliable and provides lower complexity.