• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.10a
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• pp.175-175
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• 2003

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.10a
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• pp.137-137
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• 2003

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.10a
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• pp.99-99
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• 2003

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.74-78
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• 2002

Ultra-Precision CNC polishing system including on-machine measurement system, a corrective polishing algorithm is developed. The unit removal profiles for various polishing tools and analyzed and tested and dwell time distributions and residual errors for a target removal shape are calculated. The corrective polishing algorithm is tested with various workpieces. This result will be used for the software development of the CNC polishing system.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.915-919
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• 2003

This paper presents a fuzzy-motion-control based tracking algorithm of mobile robots, which uses the geometrical information derived from the active stereo-vision system mounted on the mobile robot. The active stereo-vision system consists of two color cameras that rotates in two angular dimensions. With the stereo-vision system, the center position and depth information of the target object can be calculated. The proposed fuzzy motion controller is used to calculate the tracking velocity and angular position of the mobile robot, which makes the mobile robot keep following the object with a constant distance and orientation.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.12
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• pp.62-68
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• 2009

In this paper, we investigate a new method to measure the thickness of thin transparent objects utilizing a step index multi-mode optical fiber sensor. The method mainly depends on the refraction rate of transparent target, the diameter of optical fibers and the distance to reflector. We confirmed the effects of these parameters through the experimental verification tests. The comparison between the theoretical vs. analytical results shows good agreements with each other. The proposed model also enables users to measure the thickness of thin transparent objects without considering the reflection from the target. This approach provides simple, cost-effective and non-contact solutions to measure the thickness.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.208-211
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• 2005

The volumetric interferometer, which uses the interference of wavefronts emitted from two single mode fibers, measures the target position in 3-D. In this paper, we suggest a new calculation method which doesn't need a non-linear optimization and an initial guess. We find the relationship between the coefficients of the Zernike polynomials for a spherical wavefront and its center and reconstruct a spherical wavefront by using the Zernike polynomials from two interference fringes like a lateral shearing interferometer. The target position can be obtained from the coefficients of the Zernike polynomials of the reconstructed wavefront. We can get the target position in 3-D with $sub-{\mu}m$ errors in a simulation.

• Journal of Korea Multimedia Society
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• v.25 no.2
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• pp.247-256
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• 2022

Visual tracking of selected target objects is fundamental challenging problems in computer vision. Object tracking localize the region of target object with bounding box in the video. We propose a Siam-FPN based custom fully CNN to solve visual tracking problems by regressing the target area in an end-to-end manner. A method of preserving the feature information flow using a feature map connection structure was applied. In this way, information is preserved and emphasized across the network. To regress object region and to classify object, the region proposal network was connected with the Siamese network. The performance of the tracking algorithm was evaluated using the OTB-100 dataset. Success Plot and Precision Plot were used as evaluation matrix. As a result of the experiment, 0.621 in Success Plot and 0.838 in Precision Plot were achieved.

• Journal of Computational Design and Engineering
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• v.1 no.2
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• pp.88-95
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• 2014

Because the cost of performance testing using actual products is expensive, manufacturers use lower-cost computer-aided design simulations for this function. In this paper, we propose using hexahedral meshes, which are more accurate than tetrahedral meshes, for finite element analysis. We propose automatic hexahedral mesh generation with sharp features to precisely represent the corresponding features of a target shape. Our hexahedral mesh is generated using a voxel-based algorithm. In our previous works, we fit the surface of the voxels to the target surface using Laplacian energy minimization. We used normal vectors in the fitting to preserve sharp features. However, this method could not represent concave sharp features precisely. In this proposal, we improve our previous Laplacian energy minimization by adding a term that depends on multi-normal vectors instead of using normal vectors. Furthermore, we accentuate a convex/concave surface subset to represent concave sharp features.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.950-955
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• 2001

For the development of an ultra-precision CNC polishing system including on-machine measurement system, we study a corrective polishing algorithm. We analyze and test the unit removal profiles for a ball type polishing tool. Using these results we calculate dwell time distributions and residual errors for a target removal shape. We use the polishing simulation method and feed rate calculation method for the dwell time calculation. We test corrective polishing algorithm with an optical glass. The target removal shape is a sine wave that has amplitude 0.3 micro meters. We find this polishing process has a machining resolution of nanometer order and is effective for sub-micrometer order machining. This result will be used for the software development of the CNC polishing system.