Browsing by Author "Yeh, YM"

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A digital camcorder image stabilizer based on gray coded bit-plane block matching
(2000)
Yeh, YM
;
Wang, SJ
;
Chiang, HC
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
In this paper, we proposed an efficient algorithm to do image stabilization for digital camcorder. This approach is based on gray-coded bit-plane block matching to eliminate the unpleasing effect caused by involuntary movement of camera holders. To improve moving object detection and stabilization performance, a frame is divided into several blocks to do localized motion estimation. Based on our architecture, the temporal correlation is used at the motion unit to efficiently detect moving objects and panning conditions. To compensate for camera rotation, an energy minimization is also applied to calculate the coefficients of affine transform without many complicated computations. Having considered both programming flexibility and hardware efficiency, the motion decision and motion compensation units are coded in a microprocessor that interconnects with the stabilization hardware. The proposed stabilizer is now implemented on FPGA 10K 100.
Digital camcorder image stabilizer based on gray-coded bit-plane block matching
(2001-10-01)
Yeh, YM
;
Chiang, HC
;
Wang, SJ
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
We propose an efficient algorithm to eliminate the nonpleasing effect caused by involuntary hand movement of camera holders. In our approach, 1-bit gray-coded bit-plane block matching, instead of 8-bit gray-level block matching, is used to greatly simplify the computation of motion estimation. This computation saving makes possible a finer division of image frame and thus facilitates the employment of a much more robust procedure for motion decision. To deal with various interfering factors in motion estimation, the temporal information of each local motion vector is also used to efficiently distinguish random-like movement from temporally correlated movement. To compensate for camera rotation, an affine model is used in the motion compensation unit without adding too much computation load. Having considered both programming flexibility and hardware efficiency, the motion decision unit and the motion compensation unit are coded in a microprocessor that interconnects with the stabilization hardware, which consists of the motion estimation unit and the digital zooming unit. A slightly simplified version of the proposed stabilizer is implemented on a field programmable gate array (FPGA) board. (C) 2001 Society of Photo-Optical Instrumentation Engineers.
Nanomechanical properties of nanocrystalline Ni-Fe mold insert
(2004-06-09)
Yeh, YM
;
Tu, GC
;
Fang, TH
;
材料科學與工程學系
;
Department of Materials Science and Engineering
Nanocrystalline Ni-Fe alloy micro-mold inserts were fabricated by UV lithographic technology and pulse current electroforming process. The structure, surface and mechanical properties of Ni-Fe alloys were evaluated under different pulse current electroforming processes via X-ray diffraction (XRD), scanning probe microscope (SPM), nanoindentation, and scanning transmission electron microscope (STEM). The results show that when Fe content of the alloys increase by over 10% the grain size of Ni-Fe alloys was < 20 nm. The finer the grain of Ni-Fe alloys the higher the hardness, which is above 9 GPa. By controlling the variation of current density and duty cycle, the surface roughness of Ni-Fe alloys is < 10 nm and the surface friction coefficient is about 0.2. The results of the microelectroforming process revealed that the Fe contents was able to suppress grain growth and induced the formation of dense Ni-Fe alloys and improved the mechanical properties of the Ni-Fe alloys. (C) 2003 Elsevier B.V. All rights reserved.
Simulation analysis and experimental verification of LIGA-like process for Ni-Fe micromold insert with taper angle
(2004-11-01)
Fu, MN
;
Yeh, YM
;
Tu, GC
;
材料科學與工程學系
;
Department of Materials Science and Engineering
The LIGA (a German acronym for lithographic, gavanoformung, abformung) (or LIGA-like) process involving lithography, electroforming, and molding is one of the most important microfabrication technologies for fabricating high-aspect-ratio 3-D microstructures. In this study we use CFX software to simulate the flow field in the micromold insert electroforming process and investigate the mass transfer effect, as well as the flow field and mass transfer for different taper angles and aspect ratios for a microtemplate under different flow speeds, in order to understand the effect of the geometrical shape of the template on the electroforming process, thus to obtain the optimum physical electroforming model. In this study, we will also perform a practical electroforming process at different aspect ratios and different taper angles of the microtemplate, in order to verify the results of the simulation. From the results of the simulation, it is found that the taper angle increases the speed of the plating solution at the vent, and a good equilibrium is achieved at a taper angle of 30degrees-45degrees. Since taper angle significantly affects the mass transfer effect, it can be used to increase the mass transfer effect in high-aspect-ratio and small holes. This result has been verified using a practical electroforming Ni-Fe micromold insert.
Simulation analysis and experimental verification of UV-LIGA process for high-aspect-ratio Ni-Fe micro-mold insert
(2003-10-01)
Yeh, YM
;
Tu, GC
;
Fu, MN
;
材料科學與工程學系
;
Department of Materials Science and Engineering
UV (ultra violet)-LIGA (a German acronym for lithographic, gavanoformung, abformung), a low-cost microcomponent manufacturing technology for micro-electromechanical systems (MEMS), combines the UV patterning of thick photoresist layers with the molding of the resulting patterns by electroforming. It enables mass production of microcomponents using microinjection molding or hot embossing technology. This paper addresses the characteristics of the flow field and the mass transfer effect during micro-electroforming processes. A micro-electroforming experiment is conducted and a simulation is performed to determine optimal conditions for fine surface forming by micro-electroforming. Results show that a smaller diameter of a hole corresponds to poorer plating bath transfer. Plating bath can be replenished by increasing the rotation speed of the electrodes. However, mass transfer is still limited in holes with a high aspect ratio. The theoretical results of simulation analysis were verified by conducting practical electroforming experiments.