Browsing by Author "Liu, Chin-Wei"

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Accelerating Vanishing Point-Based Line Sampling Scheme for Real-Time People Localization
(2017-03-01)
Liu, Chin-Wei
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Chen, Hua-Tsung
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Lo, Kuo-Hua
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Wang, Chih-Jung
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Chuang, Jen-Hui
In advanced video surveillance systems, people localization is usually a part of the complete system and should be accomplished in a short time so as to reserve sufficient processing time for subsequent high-level analysis, such as abnormal event/ behavior detection and intruder detection. Hence, in addition to localization accuracy, computational efficiency is of critical importance as well. In this paper, we adopt a vanishing point-based line sampling scheme and propose a fast multicamera people localization approach capable of locating a crowd of dense people and estimating their heights in a fairly short time with high accuracy. For each camera view, sample lines, originated from a vanishing point, of foreground objects are projected onto the ground plane. Then, people locations are estimated by detecting the ground regions containing a high density of the projected lines. Enhanced from some previous works, the proposed approach does not require processing steps of high computation cost, such as projecting all foreground pixels of all views to multiple reference planes or computing pairwise intersections of projected sample lines at different heights. In addition, some novel acceleration modules, such as torso validation and physical rule-based filtering, are developed to further reduce the computation time of people localization. The experiments on real surveillance scenes validate that the proposed approach achieves significant speedup (up to 186%) over state-of-the-art techniques while still ensure a comparably high localization accuracy, even for crowded scenes with serious occlusions.
AN AFFINITY SENSOR IMPROVED BY EWOD ACTUATOR-BASED MICROFLUIDIC CHIP
(2009-12-01)
Liu, Chin-Wei
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Lin, Chi-Chang
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Chen, Li-Chia
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Fan, Shih-Kang
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Chang, Hsien-Chang
We propose an improved immunoassay method with EWOD-based microfluidic biochip. Electro-wetting on dielectric (EWOD) is based on contact angle-changed phenomenon of droplet on the channel surface. The reactant-containing droplet can be moved from reservoir to a modified electrode area, which a stir function can be provided by controlling AC electro-osmosis flow (ACEOF). The immunochemistry reaction takes place on our modified area via electro-wetting actuation, and the signal from fluorescent or electrochemical impedance spectroscopy (EIS) was used to confirm the performance of designed element.
Efficient Calibration for Multi-plane Homography Using a Laser Level
(2015)
Tai, Yen-Chou
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Liu, Chin-Wei
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Chen, Yong-Sheng
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Chuang, Jen-Hui
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資訊工程學系
An efficient calibration method for multi-plane homography is proposed in this paper. Two laser levels are used to cast laser lines to construct virtual poles in the environment without deploying real objects. HSV color model, Hough transform, and least squares method are applied to locate the laser lines in the captured images. Using the features of vanishing line and the view-invariant cross-ratio model, the 3-D coordinate of the camera can be estimated. The multi-plane homography between camera image and the world space can be derived based on two layers homography. The first layer homography relates the ground and the image, whereas the second layer homography can be efficiently obtained using the first layer homography and the virtual poles. Experimental results show that the virtual poles and the derived homography are both accurately estimated.
Highly reliable integrated amorphous silicon thin film transistors gate driver
(2007)
Liu, Chin-Wei
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Tai, Ya-Hsiang
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光電工程學系
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Department of Photonics
A reliable shift register consisted of amorphous silicon thin film transistors (a-Si TFTs) is proposed for scan driver circuit of active matrix liquid crystal display (AMLCD). The lifetime of proposed circuit is evaluated based on the reliability measurement data of the a-Si TFTs used and it is estimated to over 5000 hours. Therefore, a highly reliable scanning circuit can be achieved.
MI3: Multi-Intensity Infrared Illumination Video Database
(2015-01-01)
Chan, Chia-Hsin
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Chen, Hua-Tsung
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Teng, Wen-Chih
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Liu, Chin-Wei
;
Chuang, Jen-Hui
Vision-based video surveillance systems have gained increasing popularity. However, their functionality is substantially limited under nighttime conditions due to the poor visibility caused by improper illumination. Equipped on night vision cameras, ordinary infrared (IR) illuminators of fixed-intensity usually lead to the imaging problem of overexposure (or underexposure) when the object is too close to (or too far from) the camera. To overcome this limitation, we use a novel multi-intensity IR illuminator to extend the effective range of distance of camera surveillance, and establish in this paper the MI3 (Multi-Intensity Infrared Illumination) database based on such an illuminator. The database contains intensity varying video sequences of several indoor and outdoor scenes. Ground truths including people counting and foreground labelling are provided for different research usages. Performances of related algorithms are tested for demonstration and evaluation.