教師著作

Permanent URI for this collectionhttp://rportal.lib.ntnu.edu.tw/handle/20.500.12235/31268

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Author: search.filters.author.Ti-Ho Wang

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Now showing 1 - 10 of 11
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    Three-Dimensional Measurement of a Remote Object with a Single CCD Camera
    (2009-02-12) Ti-Ho Wang; Chen-Chien Hsu; Chun-Wei Huang; Yu-Ching Lu
    This paper presents a novel method by regulating the height of a CCD camera to measure the width and height of a targeted object. That is, three-dimensional measurement can be obtained with the use of a single CCD camera. To facilitate the measurement using various kinds of CCD cameras, parameters pertinent to the cameras can be established via a proposed mechanism in this paper. As a result, any kinds of CCD cameras can be used to perform three dimensional measurement of a targeted object via software implementation of the proposed measuring method. No changes to the circuits or structure of the camera are required.
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    Noninvasive Radial Pressure Waveform Estimation by Transfer Functions Using Particle Swarm Optimization
    (2007-08-26) Ti-Ho Wang; Chen-Chien Hsu; Po-Chou Chen
    Waveforms of blood pressure contain very important signals of life. Although blood pressure can be continuously measured by an intra arterial catheter, this invasive method introduces risks to patients. Knowing that blood pressure can change in just a few seconds or minutes without a sensible feeling, the waveforms of blood pressure are capable of conveying substantial cardiovascular information. Traditional Chinese medicine also uses radial pressure information in the form of pulses to diagnose diseases by sensing the signals from the fingertips. Therefore, a noninvasive method in measuring blood pressure waveforms is proposed in this paper, based on which we can use the signals of fingertip photoplethysmogram to reconstruct radial pressure waveforms. Characteristics of various photoplethysmogram will be categorized into 3 clusters by using fuzzy C-mean clustering. A particle swarm optimization scheme is then esblihed to search for an optimal transfer function model for estimating the radial pressure waveforms. Experiment results show that correlation ratio of the transformed waveforms can be as high as 0.89, much better than the results via the ARX technique.
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    Real-Time Tracking of Human Body Based on Discrete Wavelet Transform
    (2007-01-19) Shyang-Li Chang; Chen-Chien Hsu; Tsung-Chi Lu; Ti-Ho Wang
    A novel human body tracking system based on discrete wavelet transform is proposed in this paper based on color and spatial information. The configuration of the proposed tracking system is very simple, consisting of a CCD camera mounted on a rotary platform for tracking moving objects. By using the position information of objects in the image frame captured by the camera, the rotary platform is controlled to position the tracking object around the central area of images to improve tracking efficiency. Thanks to the use of discrete wavelet transform, computations can be significantly reduced while achieving real-time tracking.
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    Distance Measurement Using a Digital Camera
    (2006-11-11) Ti-Ho Wang; Ming-Chih Lu; Chen-Chien Hsu; Cheng-Pei Tsai; Cheng-chuan Chen
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    Three dimensional distance measurement based on single digital camera
    (2007-01-19) Ti-Ho Wang; Ming-Chi Lu; Chen-Chien Hsu; Yin Yu Lu; Cheng-Pei Tsai
    This paper proposes a 3D space distance measuring method to accomplish non-contact 3D space distance measuring by using a digital camera or digital video camera. The measuring principle of the proposed method in this paper is to learn the present camera shooting distance and the horizontal or vertical distance between the given points according to the number of pixels of the image in horizontal motion corresponding to the moving digital video camera or digital camera. The measuring structure proposed in this paper does not employ image graphic recognition or image signal analysis method to accomplish distance measuring, therefore, high-speed micro-computer and Digital Signal Processor are not used. All the distance measuring data come from a single horizontal scanning line. Only by modifying the system software of the digital video cameras (digital cameras), all makes of digital video cameras or digital cameras can have the feature of measuring 3D space distance.
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    Liquid-Level Measurement Using a Single Digital Camera
    (Elsevier, 2009-05-01) Ti-Ho Wang; Ming-Chih Lu; Chen-Chien Hsu; Cheng-chuan Chen; Jia-Dong Tan
    An imaged-based measurement system using a single digital camera and a circular float to measure fill levels in liquid tanks is proposed in this paper. By choosing the float in a different color from that of the liquid in the tank, pixel counts of the float in the image captured by the camera can be calculated with the use of chrominance filtering and thresholding techniques. Based on an established relationship between the pixel counts of the diameter of the float in the image and the photographing distance, the measuring system can effectively measure the liquid level based on the images captured. Because pixel counts of the float in the image are first determined for calculating the diameter of the float, a subpixel resolution during the measurement can be achieved. As a result, measuring precision as well as accuracy via the proposed system can be significantly improved.
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    A Problem of Infrared Electronic-Toll-Collection Systems: the Irregularity of the LED Radiation Pattern and the Emitter Design
    (IEEE Intelligent Transportation Systems Society, 2011-03-01) Wern-Yarng Shieh; Chen-Chien Hsu; Ti-Ho Wang
    According to our measurements, the radiation pattern of many low-cost commercial light-emitting diodes (LEDs) is not smooth. Some LEDs even have serious irregularities that affect the performance of infrared communication systems. For systems where a definite communication area is required, such as electronic-toll-collection (ETC) applications, this problem is particularly serious. In this paper, we first present our measured results for the radiation pattern of several typical low-cost commercial LEDs, showing that almost all of them are irregular to some extent. We then use the most acceptable model with a suitable half-intensity angle to construct the emitter of an ETC system. The design was calculated with the aid of an optimization algorithm to determine the mounting angle for each LED such that the system has an extended communication area in the longitudinal direction, i.e., in the vehicle traveling direction, and can withstand high signal attenuation. For a typical LED with half-intensity angle Φ1/2 = 13°, a very simple two-group structure for the emitter is obtained, and the analysis results are verified by experimental measurements.
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    Design of Infrared Electronic-Toll-Collection Systems with Extended Communication Areas and Performance of Data Transmission
    (IEEE Intelligent Transportation Systems Society, 2011-03-01) Wern-Yarng Shieh; Chen-Chien Hsu; Shen-Lung Tung; Po-Wen Lu; Ti-Ho Wang; Shyang-Lih Chang
    Based on our previous works in the design of an infrared emitter for electronic-toll-collection (ETC) applications, we use the unidirectional cosinen functions to approximate the irregular radiation pattern for typical infrared low-cost commercial light-emitting diodes (LEDs) with a half-intensity angle Φ1/2 = 10°. With the aid of this approximation, the main characteristics of the performance of an infrared ETC system utilizing this type of LED as the emitter can be investigated based on the received signal strength of the system. For on-off keying, a simple model connecting the received signal strength and the bit error rate (BER) of the system is further established. From the calculated or the measured received signal strength of the system, it is not difficult to estimate the system performance in terms of the BER by this simple model. Roughly speaking, for a typical setting of the circuit parameters and a typical uplink and downlink data-transmission protocol, the data transmission can be very successful in terms of a very low BER if the received signal strength is 1.3 times stronger than the signal strength received at the communication boundary. The emitter presented in this paper is able to produce a relatively extended communication area in the vehicle-traveling direction, resulting in longer communication time interval for the data transmission between the onboard unit (OBU) and the roadside unit (RSU) than conventional emitters. Furthermore, the design presented in this paper is validated by experimental measurement to demonstrate its effectiveness.
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    Three Dimensional Measurement Based on Image Shift and Its Applications
    (World Scientific and Engineering Academy and Society (WSEAS), 2007-05-01) Ti-Ho Wang; Ming-Chih Lu; Chen-Chien Hsu; Yin-Yu Lu; Cheng-Pei Tsai
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    Real-Time Tracking of Human Body Based on Discrete Wavelet Transform
    (World Scientific and Engineering Academy and Society (WSEAS), 2007-05-01) Chen-Chien Hsu; Tsung-Chi Lu; Ti-Ho Wang