Browsing by Author "Chao, TY"

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Comparative study of Ni-P-diamond and Ni-P-CNT nanocomposite films
(2006)
Chao, TY
;
Shen, GR
;
Cheng, YT
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
Ni-P-diamond and Ni-P carbon nanotube (CNT) nanocomposite films have been synthesized and compared in this paper. Because diamond has different shapes and sizes than CNTs, the nanocomposite films exhibit distinct characteristics. Nanoindentation measurements show that the Young's modulus and hardness of the Ni-P-CNT nanocomposite film electroplated in a bath with 0.028 g/L CNTs increase to 665.9 +/- 29.5 GPa and 28.9 +/- 4.22 GPa, respectively, which is about four times larger than that of pure nickel. On the contrary, the modulus and hardness of the Ni-P-diamond nanocomposite films decrease with the incorporation of the nanodiamond powders due to the formation of voids and cracks, even though both diamond and CNTs have similar Young's modulus and hardness. For the Ni-P-diamond film plated in the bath with 2.0 g/ L nanodiamonds, the values are reduced to 110.5 +/- 4.3 and 2.3 +/- 0.1 GPa. Nevertheless, the electrothermal actuators made of both Ni-P-CNT and Ni-P-diamond composites can provide four times the maximum elongation, larger than that made of pure nickel. With the same displacement, the input power of the nanocomposite actuators is much less than that of the pure Ni one. This study reveals potential applications for nano/microelectromechanical systems fabrication using both Ni-P-diamond and Ni-P-CNT nanocomposites due to their distinctive physical properties and compatibility with contemporary complementary metal oxide semiconductor manufacturing processes. (c) 2005 The Electrochemical Society. [DOI: 10.1149/ 1.2133324] All rights reserved.
Ni-P-CNTs nanocomposite film for MEMS applications
(2004)
Shen, GR
;
Tsai, LN
;
Chao, TY
;
Cheng, YT
;
Lin, TK
A Ni-P-CNTs (electroless phosphorus nickel-carbon nanotubes) nanocomposite film synthesis and related processes for MEMS device fabrication have been successfully developed and presented in this paper. With a special acid oxidative method, a well-dispersed nickel-CNTs colloidal solution has been produced without any aggregation, very suitable for microstructure fabrication. The nano-indentation measurement indicates that the Young's modulus and hardness of the Ni-P-CNTs nanocomposite film plated in the bath with 0.028g/L CNTs can greatly increase up to 666Pa and 29GPa, respectively, which is four times larger than that of pure nickel: The performance improvement of the electro-thermal microactuator made of the nanocomposite, including device strength and power efficient, have been proved similar to the Ni-diamond composites [1]. With the same power input, the device can provide 4 times elongation longer than that made of pure nickel. The mechanical strength of the actuator can also be enhanced to sustain the input power with two times larger than the pure one.
Stereoscopic correspondence by applying physical constraints and statisitical observations to dissimilarity map
(2000)
Chao, TY
;
Wang, SJ
;
Hang, HM
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
To deal with the correspondence problem in stereo imaging, a new approach is presented to find the disparity information on a newly defined dissimilarity map (DSMP). Based on an image formation model of stereo images and some statistical observations, two constraints and four assumptions are adopted. In addition, a few heuristic criteria are developed to define a unique solution. All these constraints, assumptions and criteria are applied to the DSMP to find the correspondence. At first, the Epipolar Constraint, the Valid Pairing Constraint and the Lambertian Surface Assumption are applied to DSMP to locate the Low Dissimilarity Zones (LDZs). Then, the Opaque Assumption and the Minimum Occlusion Assumption are applied to LDZs to obtain the admissible LDZ sets. Finally, the Depth Smoothness Assumption and some other criteria are applied to the admissible LDZ sets to produce the final answer. The focus of this paper is to find the constraints and assumptions in the stereo correspondence problem and then properly convert these constraints and assumptions into executable procedures on the DSMP. In addition to its ability in estimating occlusion accurately, this approach works well even when the commonly used monotonic ordering assumption is violated. The simulation results show that occlusions can be properly handled and the disparity map can be calculated with a fairly high degree of accuracy.
Synthesizing new views from a pair of stereo images
(1998)
Chao, TY
;
Hang, HM
;
Wang, SJ
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
Our goal in this study is to construct a 3-D model from a pair of(stereo) images and then project this 3-D model to image planes at new locations and orientations. me first compute the disparity map from a pair of stereo images. Although the disparity map may contain defects, we can still calculate the depth map of the entire scene by filling in the missing (occluded) pixels using bilinear interpolation. One step further, we synthesize new stereo images at different camera locations using the 3-D information obtained from the given stereo pair. The disparity map used to generate depth information is one key step in constructing 3-D scenes. Therefore, in this paper we investigate various types of occlusion to help analyzing the disparity map errors and methods that can provide consistent disparity estimates. The edge-directed Modified Dynamic Programming scheme with Adaptive Window (MDPAW), which significant improves the disparity map estimates, is thus proposed. Our preliminary simulations show quite promising results.