Browsing by Author "Kao, JH"

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A potential-based path planning of articulated robots with 2-DOF joints
(2005)
Chuang, JH
;
Lin, CC
;
Kao, JH
;
Hsieh, CT
;
資訊工程學系
This paper proposes a potential-based path planning algorithm of articulated robots with 2-DOF joints. The algorithm is an extension of a previous algorithm developed for 3-DOF joints. While 3-DOF joints result in a very straightforward potential minimization algorithm, 2-DOF joints are obviously more practical for active operations. The proposed approach computes repulsive force and torque between charged objects by using generalized potential model. A collision-free path can be obtained by locally adjusting the robot configuration to search for minimum potential configurations using these force and torque. The optimization of path safeness, through the innovative potential minimization algorithm, makes the proposed approach unique. In order to speedup the computation, a sequential planning strategy is adopted. Simulation results show that the proposed algorithm works well compared with the algorithm for 3-DOF joints, in terms of collision avoidance and computation efficiency.
Automatic chromosome classification using medial axis approximation and band profile similarity
(2006)
Kao, JH
;
Chuang, JH
;
Wang, TP
;
資訊工程學系
;
Department of Computer Science
Automated chromosome classification is an essential task in cytogenetics and has been an important pattern recognition problem. Numerous attempts were made in the past to characterize chromosome to perform clinical and cancer cytogenetics research. It is important to determine optimum features and develop feature extraction schemes for chromosome classification. In this paper we propose novel approaches for medial axis determination and profile matching of human chromosome. The medial axis determination plays a critical role for precise and complete extraction of band patterns of chromosomes. The features of the band profile obtained along the axis are then used in the classification process. In particular, the medial axis is obtained by simple cross-section analysis and the classification is accomplished through iterative pairing of band profiles. According to the experimental results, the developed automatic system can efficiently extract band profiles of the chromosomes along their medial axes, and satisfactory chromosome classification results can be obtained.
Identity verification by relative 3-D structure using multiple facial images
(2005-07-01)
Kao, JH
;
Chen, YH
;
Chuang, JH
;
資訊工程學系
;
Department of Computer Science
Identity verification is one of the critical issues in the sector of security and has been emerging as an active research area. In recent years, technologies using biological features to address problems of identity verification have attracted numerous research interests. For examples, fingerprint recognition, voice recognition and pattern of blood vessels in the retina have spanned many commercial applications. However, special and expensive equipments such as fingerprint readers and iris scanners are often required and people have to be in unpleasant poses occasionally. This paper presents a study on computer vision technique and its application in face recognition to achieve identity verification. With multiple facial images taken from different view angles, relative affine structures are computed and are used as measurements. To that end, the explicit relationship between relative affine structure and the cross ratio which is a view-invariant under perspective projection is also addressed. The proposed method neither requires camera calibration nor reconstructs 3D models. According to simulation results, the developed approach can achieve satisfactory results given the feature points of facial images. © 2004 Elsevier B.V. All rights reserved.
Ultrathin N2O-oxide with atomically flat interfaces
(1997-05-01)
Chin, A
;
Chen, WJ
;
Lin, BC
;
Kao, JH
;
Tsai, C
Silicon oxide has been grown in a low pressure furnace using N2O. An atomically fiat SiO2 (N2O)/Si interface, as determined by high resolution transmission electron microscopy, has been achieved by desorbing the native oxide in situ for oxide thicknesses 11 to 38 Angstrom. The thickness variation of a 20 Angstrom N2O-oxide, grown on a 4 in. substrate <1 Angstrom. The excellent uniformity is attributed to the increased mean-free path of N2O molecules in the low pressure environment. Since only one Si plane was distorted beneath the N2O-oxide/Si interface, this suggests that thermal stress is not the limiting factor for obtaining an atomically smooth interface.
Ultrathin N2O-oxide with atomically flat interfaces
(1997-05-01)
Chin, A
;
Chen, WJ
;
Lin, BC
;
Kao, JH
;
Tsai, C
Silicon oxide has been grown in a low pressure furnace using N2O. An atomically fiat SiO2 (N2O)/Si interface, as determined by high resolution transmission electron microscopy, has been achieved by desorbing the native oxide in situ for oxide thicknesses 11 to 38 Angstrom. The thickness variation of a 20 Angstrom N2O-oxide, grown on a 4 in. substrate <1 Angstrom. The excellent uniformity is attributed to the increased mean-free path of N2O molecules in the low pressure environment. Since only one Si plane was distorted beneath the N2O-oxide/Si interface, this suggests that thermal stress is not the limiting factor for obtaining an atomically smooth interface.