• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.410-413
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• 2001

This paper is to model a 3D-shape product applying mathematically the data acquired from a 3D scanner and using an Automatic Design Program. The research studied in the reverse engineering up to now has been developed continuously and surprisingly. However, forming 3D-shape solid models in CAE and CAM, based on the research, the study leaves much to be desired. Especially, analyses and studies reverse-designing automatically using measured data after manufacturing. Consequently, we are going to acquire geometric data using an 3D scanner in this study with which we will open a new field of reverse engineering by a program whic hcan design a 3D-shape solid model in a CAD-based program automatically.

• ETRI Journal
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• v.45 no.6
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• pp.1035-1045
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• 2023

We propose a novel graphics processing unit (GPU) algorithm that can handle a large-scale 3D fast Fourier transform (i.e., 3D-FFT) problem whose data size is larger than the GPU's memory. A 1D FFT-based 3D-FFT computational approach is used to solve the limited device memory issue. Moreover, to reduce the communication overhead between the CPU and GPU, we propose a 3D data-transposition method that converts the target 1D vector into a contiguous memory layout and improves data transfer efficiency. The transposed data are communicated between the host and device memories efficiently through the pinned buffer and multiple streams. We apply our method to various large-scale benchmarks and compare its performance with the state-of-the-art multicore CPU FFT library (i.e., fastest Fourier transform in the West [FFTW]) and a prior GPU-based 3D-FFT algorithm. Our method achieves a higher performance (up to 2.89 times) than FFTW; it yields more performance gaps as the data size increases. The performance of the prior GPU algorithm decreases considerably in massive-scale problems, whereas our method's performance is stable.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.40 no.6
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• pp.31-40
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• 2003

Most face recognition systems are based on 2D images and applied in many applications. However, it is difficult to recognize a face when the pose varies severely. Therefore, head pose estimation is an inevitable procedure to improve recognition rate when a face is not frontal. In this paper, we propose a novel head pose estimation algorithm for 3D face recognition. Given the 3D range image of an unknown face as an input, we automatically extract facial feature points based on the face curvature. We propose an Error Compensated Singular Value Decomposition (EC-SVD) method based on the extracted facial feature points. We obtain the initial rotation angle based on the SVD method, and perform a refinement procedure to compensate for remained errors. The proposed algorithm is performed by exploiting the extracted facial features in the normaized 3D face space. In addition, we propose a 3D nearest neighbor classifier in order to select face candidates for 3D face recognition. From simulation results, we proved the efficiency and validity of the proposed algorithm.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.8
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• pp.38-45
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• 2016

The objective of this research is to develop a method of improving MEP facility management based on 3D reverse engineering. Recently, 3D image scanning-based reverse engineering has been implemented in the fields of architecture, construction and (manufacturing). In the case where there are many objects and the MEP system is complicated, 3D reverse engineering is applied in semiconductor factories, because facility maintenance works cause the 2D drawing to be different from the original one. The 3D point cloud data obtained from 3D image scanning contains accurate data and can increase the efficiency of complicated MEP facility maintenance works. For this purpose, the present research studied the technology trends and analyzed the process of 3D reverse engineering. Based on the results, a method of improving MEP facility management is established and its effects described.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.10
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• pp.1944-1949
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• 2007

In this paper, a new plane-based computational reconstruction technique for three-dimensional (3D) objects in 3D internal imaging based on a lens model is proposed. For the proposed technique, computational experiments have been carried out for various test images. Resolution of the reconstructed images is analyzed and compared with that obtained by the conventional technique. From experiments, it is shown that the resolution of a 3-D reconstructed image was improved by using the proposed technique.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.9
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• pp.1632-1652
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• 2011

This paper considers the object tracking problem in three dimensional (3-D) space when the azimuth and elevation of the object are available from the passive acoustic sensor. The particle filtering technique can be directly applied to estimate the 3-D object location, but we propose to decompose the 3-D particle filter into the three planes' particle filters, which are individually designed for the 2-D bearings-only tracking problems. 2-D bearing information is derived from the azimuth and elevation of the object to be used for the 2-D particle filter. Two estimates of three planes' particle filters are selected based on the characterization of the acoustic sensor operation in a noisy environment. The Cramer-Rao Lower Bound of the proposed 2-D particle filter-based algorithm is derived and compared against the algorithm that is based on the direct 3-D particle filter.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.1318-1321
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• 2006

We describe the 3D/2D convertible color display based on modified integral imaging. In the proposed method a color liquid crystal display panel is used as a transmission-type display panel and enables a color 3D/2D convertible display system. The principle of the proposed method will be explained and methods to overcome the color dispersion problem will be discussed also.

• 전자공학회논문지 IE
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• v.43 no.4
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• pp.105-114
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• 2006

In this paper, 3D input and output systems for a web-based real-time 3D video communication system using IEEE 1394 digital cameras, Intel Xeon Server system and Microsoft Directshow library is proposed. And some conditions for optimizing the operations of the stereo camera, 3D display and signal processing system are analyzed. Input & output systems are carefully selected, which can satisfy the required optimization conditions and the final 3D video communication system is implemented by using three optimized devices. The overall control system is developed with Microsoft Visual C++.Net and Microsoft DirectX 9.1 SDK. Some experimental results show that the observer can feel the natural presence from multi-view(4-view) 3D video of server system in real-time and also can feel the natural presence from 3D video of client system and finally suggest an application possibility of the proposed web-based real-time 3D video communication in real fields.

• Proceedings of the KSME Conference
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• 2001.11b
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• pp.394-399
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• 2001

A new stereoscopic PIV is introduced. The system works with CCD cameras, stereoscopic photogrammetry, and a 3D-PTV principle. Virtual images are produced for the construction of a benchmark testing tool of PIV techniques. The arrangement of the two cameras is based on angular position. The calibration of cameras and the pair-matching of the three-dimensional velocity vectors are based on 3D-PTV technique.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.12
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• pp.1071-1076
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• 2003

The nonlinear properties and their stability of ZPCCD- based varistors, which are composed of ZnO P $r_{6}$ $O_{ll}$ - CoO-C $r_2$ $O_3$-D $y_2$ $O_3$-based ceramics, were investigated in the D $y_2$ $O_3$ content range of 0.0∼2.0 mol%. The incorporation of D $y_2$ $O_3$ greatly affected the nonlinear properties and the best nonlinearity was obtained from 0.5 mol% D $y_2$ $O_3$ with nonlinear exponent of 66.6 and leakage current of 1.2 $\mu$A. Further addition of D $y_2$ $O_3$ deteriorated the nonlinear properties. In stability against DC accelerated aging stress state: 0.95 $V_{1mA}$/15$0^{\circ}C$/24 h, the 0.5 mol％ D $y_2$ $O_3$-doped varistor exhibited the highest stability, in which the variation rate of varistor voltage and nonlinear exponent are -1.9% and 10.5%, respectively. The remainder varistors resulted in thermal runaway due to low density of ceramics.s.s.