Browsing by Author "Wang, SJ"

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A coarse-to-fine approach for the generation and tracking of mesh objects from a natural image sequence
(2000)
Ko, JT
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Wang, SJ
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電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
In this paper, a new scheme, which automatically generates a hierarchical mesh from a real image, is proposed. First, three distinct meshes are generated according to a three-layer image pyramid. By eliminating the duplicated mesh nodes between these three meshes, a hierarchical mesh is formed. Because each hierarchy represents the image in different resolutions, this hierarchical structure can achieve progressive coding. Furthermore, to generate a dynamic mesh for an image sequence, this hierarchical structure can help to reduce the computation complexity through the tracking of mesh nodes in the sequence. A method is also proposed to predict the moving direction of mesh nodes and to facilitate the motion estimation.
A digital camcorder image stabilizer based on gray coded bit-plane block matching
(2000)
Yeh, YM
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Wang, SJ
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Chiang, HC
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電子工程學系及電子研究所
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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.
A feature-based scalable codec for image compression
(2005)
Kuo, LC
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Wang, SJ
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電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
This paper presents a feature-based scheme for image compression. In the proposed method, the features in an image are recorded by three-dimensional verge points, which are defined as high curvature points on the image surface. The verge point representation can be further condensed using B-spline control point approximation. By encoding and transmitting these control points, the features in an image could be revealed at the decoder side. Furthermore, by selecting different coding modes, the proposed method can offer diversified scalabilities, including SNR scalability, spatial scalability, and shape scalability. In addition, this coding technique is suitable for region of interest selection and transmission. Experimental results are provided to present the scalability and interactivity of the proposed method.
A flexible architecture for feature-based image editing
(2005)
Kuo, LC
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Wang, SJ
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交大名義發表
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National Chiao Tung University
This paper presents a scheme for feature-based image editing. In the proposed method, an image is decomposed into a skeleton component and a residual component. The skeleton component is obtained by performing iterative linear interpolation based on high-curvature points, which are extracted from the image surface using Hessian tensor. The residual component is obtained by subtracting the skeleton component from the original image. By manipulating the skeleton component and the residual component, several applications, such as adaptive contrast enhancement, sharpness enhancement, and shape editing, can be achieved. Experimental results are provided to verify the versatility and flexibility of this proposed architecture.
A histogram-based moment-preserving clustering algorithm for video segmentation
(2003-10-01)
Lo, CC
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Wang, SJ
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資訊管理與財務金融系註：原資管所+財金所
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Department of Information Management and Finance
Video segmentation is the first step of creating video indices for a video retrieval system. A segmentation algorithm is used to identify shots from video data. In this paper, we propose a histogram-based moment-preserving (HBMP) clustering algorithm for segmenting video data. This algorithm is a hybrid of the shot change detection approach and the clustering approach. The computational results indicate that the proposed algorithm is both effective and efficient with respect to various types of video sequence. (C) 2003 Elsevier B.V. All rights reserved.
A quantum trap MONOS memory device using AlN
(2006)
Lai, CH
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Wu, CH
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Chin, A
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Wang, SJ
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McAlister, SP
We report a IrO2-HfAlO-AlN-SiO2-Si MONOS device that displays excellent characteristics in terms of speed (100 mu s at +/- 13 V for program/erase) and memory window (3.7 V) at 85 degrees C operation. This device also shows good 10-year extrapolated data retention with a large 1.9 V window at 85 degrees C. The achieved performance compares well with the best reported memory device data. (c) 2006 The Electrochemical Society.
A systolic architecture for elliptic curve cryptosystems
(2000)
Tsai, WC
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Wang, SJ
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電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
This article presents a new systolic architecture for the main operation in an elliptic curve cryptosystem over the finite field GF(2(m)). This proposed architecture is actually a finite field multiplier and is used to implement the addition operation in the elliptic curs-e cryptosystem. We apply partitioning scheme and parallelize the main operation in a straightforward systolic architecture to speed up the operation and then apply merging and re-timing schemes in the partitioned architecture to future improve the performance of this architecture. We compare this architecture with some previously proposed systolic architectures for the finite field arithmetics. The comparison shows that our architecture offers the lowest hardware complexity. This architectures can be easily adopted to build a low-complexity elliptic curve cryptosystem.
An automatic pin identification method for a three-phase DC brushless motor
(2005-10-01)
Wang, SJ
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Cheng, CC
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Lin, SK
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Ju, JJ
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Huang, DR
The pin identification is to find the definition of each connecting pin of a three-phase brushless motor. The 11 pins of the motor can be distinguished into three groups by a simple resistance measurement method. An automatic method has two steps. In the first step, the motor is in an open-circuited mode; and the individual pins of the windings are identified by comparing back electromotive forces. A special integral is defined and used to match Hall signal pins with the Hall sensors. The polarity of each pair of the Hall signal pins is determined by the second step of a standstill method. The proposed method is illustrated and verified by an experiment.
Analytical prediction of the cogging torque and torque constant of a hybrid stepping motor
(2002-02-01)
Wang, SJ
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Lin, SK
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電控工程研究所
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Institute of Electrical and Control Engineering
We present an analytic method to efficiently calculate the torque constant and cogging torque of a hybrid stepping motor. The feature of the proposed method is its computational efficiency in that it is a useful tool for the motor design which is aimed at reducing the level of cogging torque or increasing the torque constant. This method is verified by comparing with the 3D finite element method and some experiments. (C) 2002 Elsevier Science B.V. All rights reserved.
Analytical prediction of the incremental inductance of the permanent magnet synchronous motors
(2004-07-01)
Wang, SJ
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Lin, SK
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電控工程研究所
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Institute of Electrical and Control Engineering
An analytical method for calculating the incremental line inductance of a permanent-magnet synchronous motor is proposed in this paper. First, the incremental inductance is simplified as a linear combination of the slot inductance and the air-gap inductance, which are both estimated by the equivalent magnetic circuits. The reluctance of the rotor back irons and the stator back irons are ignored when the slot inductance is calculated. However, for the calculation of the air-gap inductance, the iron saturations and the perturbations of the permanent magnet are considered. The proposed method is verified by a finite-element method.
Autoadjusting the photodetector in an optical head system for optimum focus
(2004-07-01)
Wang, SJ
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Lin, SK
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電控工程研究所
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Institute of Electrical and Control Engineering
In the assembly of an optical head system, it is required to mount the photodetector integrated chip (PDIC) in the correct position so that the astigmatism phenomenon can be achieved. The conventional means of adjustment requires an experienced engineer to shift the PDIC in the three dimension (3D) space until the S-word profile is obtained. This paper proposes an automatic method for replacing an experienced engineer, which can be formulated as an optimization problem with parameters trained by a neural network method. During the training process, a convex cost function of the 3D position is established and the minimum of this function indicates the correct position of the PDIC. In the mounting stage, the steepest descent method is then applied to search for the optimum of the trained function, so that the PDIC is automatically mounted at the optimal position.
Automatic mura detection system for liquid crystal display panels
(2006-01-01)
Fang, LT
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Chen, HC
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Yin, IC
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Wang, SJ
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Wen, CH
In this paper, we propose an automatic inspection system, which can automatically detect four types of muras on an LCD panel: cluster mura, v-band mura, rubbing mura, and light leakage mura. To detect cluster muras, the Laplacian of Gaussian (LOG) filter is used. A multi-resolution approach is proposed to detect cluster muras of different scales. To speed up the processing speed, this multi-resolution approach is actually implemented in the frequency domain. To detect v-band muras, we check the variation tendency of the projected I-D intensity profile. Then, v-band muras are detected by identifying these portions of the I-D profile where a large deviation occurs. To detect rubbing muras, we designed a frequency mask to detect distinct components in the frequency domain. To detect light leak muras, we apply image mirroring over the boundary parts and adopt the same LOG filter that has been used in detecting cluster muras. All four types of mura detection are integrated together in an efficient way and simulation results demonstrate that this system is indeed very helpful in detecting mura defects.
Automatic mura detection system for liquid crystal display panels - art. no. 60700G
(2006)
Fang, LT
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Chen, HC
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Yin, IC
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Wang, SJ
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Wen, CH
In this paper, we propose an automatic inspection system, which can automatically detect four types of muras on an LCD panel: cluster mura, v-band mura, rubbing mura, and light leakage mura. To detect cluster muras, the Laplacian of Gaussian (LOG) filter is used. A multi-resolution approach is proposed to detect cluster muras of different scales. To speed up the processing speed, this multi-resolution approach is actually implemented in the frequency domain. To detect v-band muras, we check the variation tendency of the projected I-D intensity profile. Then, v-band muras are detected by identifying these portions of the I-D profile where a large deviation occurs. To detect rubbing muras, we designed a frequency mask to detect distinct components in the frequency domain. To detect light leak muras, we apply image mirroring over the boundary parts and adopt the same LOG filter that has been used in detecting cluster muras. All four types of mura detection are integrated together in an efficient way and simulation results demonstrate that this system is indeed very helpful in detecting mura defects.
Combinational AE-AF system with fuzzy climbing search servo
(2006-01-01)
Chen, CY
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Tseng, CY
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Hung, CH
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Yin, IC
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Wang, SJ
This paper presents a combinational system, which can perform the functionalities of Auto Focus (AF) and Auto Exposure (A-E) at the same time in a very efficient manner. At the first step, this system uses a DOG (Difference of Gaussian) filter to measure image's contrast and sharpness simultaneously. Then, a fuzzy logic-based scheme is proposed for the adjustment of focus and exposure. This system can be easily implemented with low hardware complexity.
Combinational AE-AF system with fuzzy climbing search servo - art. no. 60690B
(2006)
Chen, CY
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Tseng, CY
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Hung, CH
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Yin, IC
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Wang, SJ
This paper presents a combinational system, which can perform the functionalities of Auto Focus (AF) and Auto Exposure (A-E) at the same time in a very efficient manner. At the first step, this system uses a DOG (Difference of Gaussian) filter to measure image's contrast and sharpness simultaneously. Then, a fuzzy logic-based scheme is proposed for the adjustment of focus and exposure. This system can be easily implemented with low hardware complexity.
Constrast based color segmentation with adaptive thresholds
(2002)
Chen, HC
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Chien, WJ
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Wang, SJ
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電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
In this paper, we propose a color segmentation algorithm based on contrast information and adaptive thresholds. Given a color image, instead of the commonly used achromatic difference and chromatic difference, we use achromatic contrast and chromatic contrast to represent the significance of boundary. To fit for human's visual perception, adaptive thresholds are applied to suppress perceptually faint boundaries. A complete segmentation scheme is proposed and the simulation results demonstrate the superiority of this approach in providing reasonable and reliable color segmentation.
Contrast-based color image segmentation
(2004-07-01)
Chen, HC
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Chien, WJ
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Wang, SJ
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電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
In this letter, we propose a color image segmentation algorithm based on contrast information. Given a color image, we use contrast information, instead of the commonly used derivative information, to detect edges. To fit for human's visual perception, the CIE L*a*b* color space is used and the DeltaE(ab) color difference is adopted as the measure of color contrast. A subjective experiment is made to demonstrate the weak correlation between the perceived color contrast and the levels of (L*, a*, b*). This experiment implies the feasibility of using a single-threshold scheme to suppress perceptually, faint boundaries. A complete segmentation scheme is proposed and the simulation results demonstrate the superiority of this approach in providing reasonable and reliable color image segmentation.
Critical current anisotropy and pinning in (103)YBCO superconducting thin films on SrTiO3(110) substrates
(1996)
Wu, KH
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Huang, SJ
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Wang, SJ
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Chen, SP
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Juang, JY
High quality (103) oriented YBCO superconducting thin films with T-c approximate to 89 K have been prepared by pulsed laser deposition on SrTiO3 (110) substrates. The grain morphology of the films, as revealed by both scanning electron microscopy and atomic force microscopy, shows distinct brick wall structure. The critical current densities measured along (001) direction of the substrates are about an order of magnitude higher than that measured on the other in-plane direction with no apparent weak-link behavior observed. The critical current densities in both directions, however, show a similar linear temperature dependence over a wide temperature range, indicative of a flux-creep limited mechanism. The creep rate in both cases, as fit to the Anderson-Kim creep model, is of order of 1 which is about an order of magnitude higher than that of conventional type-II superconductors. Samples co-ablated with silver were also studied. Detail mechanisms of pinning as wall as grain morphology evolutions are discussed.
Design of a voice coil motor used in the focusing system of a digital video camera
(2005-10-01)
Yu, HC
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Lee, TY
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Wang, SJ
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Lai, ML
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Ju, JJ
This paper raises a valid method to design a voice coil motor (VCM) used in the focusing system of a digital video camera (DVC). A better VCM performance, such as lower battery consumption, higher efficiency, and shorter focusing time, can be achieved by turning the diameter of a winding coil, the thickness of the magnet, and the winding spaces in a VCM.
Development of micromagnetic bearing motors with suppressed magnetic coupling effect for small form factor optical drives
(2006-04-15)
Wang, CC
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Yao, YD
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Wang, SJ
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材料科學與工程學系
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Department of Materials Science and Engineering
The aim of this paper was to design a micromagnetic bearing (MMB) motor for small form factor optical drives. A MMB motor was developed with inner and outer magnetic-ring stack structure of high permeability. These rings were arranged on the shaft above the permanent magnet of the rotor and the stator. The magnetic force between the MMB, the permanent magnet, and the stator induced the magnetic coupling effect that generated the demon friction torque loss. However, the loss was controlled well under 1.93x10(-4) N m by the proposed approach, so that the good stable system was achieved. After suppressing the loss caused by the magnetic coupling effect, the shaft can be rotated without any frictional contacts in radial direction, the running current was around 0.18 A, and the maximum speed was around 1850 rpm. It shows that the MMB demonstrates the lower friction torque loss in comparison with the conventional microball bearing (MBB). Moreover, the radial vibration of our device is 21% lower than the conventional MBB type. To verify the performance of the provided system, both the computer simulation and the experiment were performed. (C) 2006 American Institute of Physics.