Browsing by Author "Hwang, Chi-Hung"

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An image based optical lens eccentric error inspection system
(2012)
Chen, Yung-Hsiang
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Hsieh, Yao-Fang
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Hsu, Chia-Wei
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Ou-Yang, Mang
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Lee, Cheng-Chung
In this study, we have presented the prototype of optical lens eccentric error inspection system based on image processing algorithms. The traditional inspection by using the transmission or reflection measurements is limited to the geometry and size of the lens. In this study, an image based inspection system has developed target on fast, accurate and low-cost to meet the need for lens eccentric error inspection.
Confocal displacement sensor with varifocal lens
(2015)
Weng, Chun-Jen
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Lan, Tzu-Hsien
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Hwang, Chi-Hung
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Liu, Da-Ren
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Chen, Chih-Yen
a confocal displacement sensor with a varifocal lens and a multi-wavelength rainbow laser was established in this study. The surface curvature of varifocal lens was varied by different current driving so that the focal length can be easily changed. Thus, we can quickly measure the distance between the sensor head and targets by detecting the reflective power according to the principle of confocal laser. This rainbow laser can operate at four different wavelengths. The laser beams with different colors can be used to measure the dispersion of varifocal lens. The range of measuring displacement with 20X objective lens in this displacement sensor is from 4.9mm to 5.9mm. The FWHM resolution of displacement is about 70 mu m. The step-height aluminate plate was measured by this system and the error of measuring distance is less than 35 mu m (0.75%).
DESIGN OF AN AUTOMATED FEEDBACK CONTROL COOLING SYSTEM FOR SWIR LINEAR IMAGE SENSOR APPLICATION
(2010)
Chen, Chien-Hung
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Chen, Chih-Wen
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Lin, Chun-Fu
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Liao, Tai-Shan
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Hwang, Chi-Hung
Our novel automated feedback temperature controlled cooling system consists of a temperature measurement circuit, a TE cooler, a thermistor, a microcontroller, and a digital-to-analog converter and PWM algorithms. The measurement accuracy of this temperature controlled TE system was better than 0.1 degrees C and can be used for maintaining an instrument's isothermal applications. The experimental results of SWIR linear image shows that the temperature can be stably maintained at -20 degrees C, the dark output current can be reduced almost 80mV (Integration time: 100 ms) and the SNR of pixel can be improved from 48dB to 83dB as well.
Light energy transformation over a few nanometers
(2017-09-20)
Huang, Hung Ji
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Liu, Bo-Heng
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Su, James
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Chen, Po-Jui
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Lin, Chun-Ting
Continuous platinum (Pt) thin film was fabricated via the plasma-enhanced atomic layer deposition method for a study of light energy transformation over a few nanometers. Light-to-heat experiments were used to determine the oscillating size effects on electromagnetic energy transformation in quantum wells of smooth and condensed Pt thin films. For Pt-film thicknesses of around 4 nm, 7 nm and 12 nm, electromagnetic heating presented unexpectedly high energy conversion efficiency. An empirical equation acquired from the fitting of the experimental data from various thicknesses of Pt thin films was suggested to describe the oscillating electromagnetic heating and quantized energy transformation. The experimental results show that size control of the nanostructures is extremely important for future applications involving quantum effects in nano devices.
Manipulating Polycrystalline Silicon Nanowire FET Characteristics by Light Illumination
(2016-03-17)
Chen, Chien-Hung
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Lin, Chih-Heng
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Yang, Yuh-Shyong
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Hwang, Chi-Hung
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生物科技學系
Polycrystalline silicon nanowire field-effect transistor (poly-SiNW FET) has attracted many attentions in the past decade because of its ultrasensitive, label-free, and real-time response for potential sensing applications particular for biosensors. In this paper, the changes of the electric characteristics of poly-SiNW FET introduced by light illumination are studied systematically. Particularly, the red light (635 nm) and UV light (365 nm) are employed as light sources. Both lights are projected on the poly-SiNW FETs installed and are tested in air or in a vacuum (0.1 Ton) chamber. The results show that both light sources can change the electric characteristics of poly-SiNW FET which indicates that the photoelectronic effect can manipulate both n- and p-type devices of poly-SiNW FET; meanwhile, results also support the potential of poly-SiNW FET in air and in the vacuum environment for optoelectronic sensing applications.
Measuring the thickness of transparent objects using a confocal displacement sensor
(2017-01-01)
Weng, Chun-Jen
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Lu, Bo-Rong
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Cheng, Pi-Ying
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Hwang, Chi-Hung
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Chen, Chih-Yen
this paper reports on a confocal displacement sensor with varifocal lens used to measure the thickness of transparent materials. The focal length of the varifocal lens is adjusted by varying the current. Laser light passing through a transparent target lying within the range of the focal length crosses two interfaces; i.e., first from air to glass and then from glass to air. The signals associated with the interface were of higher intensity than that measure at other points along the z axis. A power meter is used to measure the power and LabVIEW is used to record a power-current graph. The current gap between the two peaks can be translated into values of displacement, indicating the thickness of the material.
Rapid displacement sensor based on fitting scan
(2016)
Ye, Zheng-Jie
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Hwang, Chi-Hung
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Cheng, Pi-Ying
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Chen, Chih-Yen
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Weng, Chun-Jen
A rapid displacement sensor with a varifocal lens based on a method of fitting scan is proposed for 3D surface profiling. The focal length of the varifocal lens can be adjusted by varying the driving current. By detecting the reflective power of the reflected laser, the displacement can be obtained. By integrating a LabVIEW program based on a Levenberg-Marquardt algorithm in this system, the measuring speed can be substantially improved. Finally, the 3D surface profile of a step-height sample was successfully scanned by this displacement sensor.
Real-time Image Data Acquisition and Inspection System for Integrated Circuit Wafer after Sawing Process
(2016)
Lin, Chun-Fu
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Fang, Hong-Ren
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Sze, Jyh-Rou
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Lin, Sheng-Fuu
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Hwang, Chi-Hung
The major defect in integrated circuit wafers after the sawing process is the unexpected cracking from the sawing lane that damages the die area. Traditional defect detection algorithms for integrated circuit wafers after the sawing process can be divided into two parts. The first part is locating the sawing lane area and the second is detecting defects in the sawing lane area. The traditional methods take too long to locate the sawing lane area. To overcome this, this paper proposes a novel method for locating the sawing lane area using low-resolution and gray-value input images. After the sawing lane area is extracted from the original image, defects can be detected by traditional defect detection methods in the sawing lane area or by the method proposed in this paper. Using the proposed defect detection method is faster and better for real-time operation than traditional methods since the proposed method is more concise. Finally, a pioneering image data acquisition and inspection system for integrated circuit wafers after the sawing process is proposed in this paper. Furthermore, the proposed system works in real time because its architecture operates quickly and its proposed algorithm is simple, using low-resolution, gray-value images. Therefore, the proposed system can operate in real time and maintain a high-level detection rate.
Real-Time Image-Based Defect Inspection System of Internal Thread for Nut
(2019-08-01)
Lin, Chun-Fu
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Lin, Sheng-Fuu
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Hwang, Chi-Hung
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Tu, Hao-Kai
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Chen, Chih-Yen
The most important components of the internal nut thread inspection process are measuring the pitch and pitch diameter value and comparing these with their respective specifications, as a test nut is considered to be abnormal when its pitch or pitch diameter does not meet specifications. This paper focuses on defects arising when the pitch diameter does not meet its specification. Because conventional contact strategies are not suited to the real-time inspection of internal thread defects, there have been a number of recent attempts to develop noncontact methods for real-time measurement. Some approaches have applied laser triangulation techniques in which reflected light is used to measure the z-axis depth on an object's surface. Although point lasers have been shown to be highly precise in measuring pitch diameter, the optical architecture involved in these approaches is complicated and, as the laser must be scanned in a pointwise manner to derive cross-sectional measurements, the measurement process is too long to be compatible with real-time defect inspection. In this papere, an image-based method employing a line laser projector was used to develop a real-time image-based nut pitch diameter defect inspection system. The proposed method, which improves upon the conventional, widely used template-matching method for rapid defect detection, was shown to be effective through experimental validation.
Real-time Middle Wave Infrared Aerial Image Capturing and Stitching System for Vegetation Observation
(2015)
Lin, Chun-Fu
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Lin, Sheng-Fuu
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Hwang, Wen-Jyi
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Chen, Yung-Hsiang
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Hwang, Chi-Hung
Over the last decades, several studies have demonstrated the reflectance effectiveness of middle wave infrared (MWIR) for discriminating among different types of vegetation, and estimating the total and leaf biomass of several forest ecosystems. Therefore, a MWIR aerial image capturing system for vegetation observation is urgently required. Furthermore, stitching those MWIR aerial images together is necessary for a panorama of the region of interest (ROI). Most traditional stitching algorithms for aerial images are designed for visible images, and are not suitable for infrared images that are noisy, blurry, or lack detail. In this paper, a novel real-time MWIR aerial image capturing and stitching system for vegetation observation is proposed. The proposed stitching algorithm for aerial infrared images improved from scale invariant feature transform (SIFT) and random M-least square can find a sufficient number of feature points easily and perform rapid calculations. Therefore, the proposed MWIR aerial image capturing and stitching system for vegetation observation can operate in real time.
Real-time pedestrian detection system with novel thermal features at night
(2014-01-01)
Lin, Chun-Fu
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Lin, Sheng-Fuu
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Hwang, Chi-Hung
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Chen, Yu-Chieh
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電控工程研究所
Since the need of pedestrian detection at night has gained more and more interest, real-time pedestrian detection system at night has begun to attract significant attention. However, the detection performance of traditional pedestrian detection system at night is still insufficient since region of interests(ROI) generation and feature extraction are designed separately and less relative. This study presents a novel pedestrian detection algorithm and the corresponding system architecture for the real-time pedestrian detection system at night. The presented pedestrian detection algorithm uses novel outline features which have strong representative for the forward direction of pedestrian. A ROI generation method which is closely related to the outline features is presented to improve the detection accuracy. A three-layer back-propagation feed-forward neural network is applied as the classifier. Since the system architecture is efficiently and the calculation of the outline feature values is simple, the presented pedestrian detection system can operate in real-time. Experimental results show that the presented outline features are significantly effective and the detection performance of pedestrian detection system at night is improved.
Real-time Pitch Diameter Measurement of Internal Thread for Nut using Laser Triangulation
(2017-01-01)
Lin, Chun-Fu
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Hwang, Chi-Hung
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Fang, Hong-Ren
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Chen, Chih-Yen
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Sze, Jyh-Rou
In traditional industrial applications, the thread plug gauge is used to check the pitch diameter of the internal thread of a nut. However, the thread plug gauge can only be used to determine whether the nut was manufactured successfully rather than to measure the value of the pitch diameter. In recent years, several studies have employed a reflected light method such as laser triangulation to scan the outline of an object. However, most research studies using laser triangulation have developed measurement algorithms for specific objects because the properties of an object's appearance and the reflective laser from that object differ greatly. Existing algorithms are consequently not suitable for scanning the outline of the internal thread of a nut and measuring its pitch diameter with laser triangulation. In this paper, we propose a novel, real-time algorithm for measuring the pitch diameter of the internal thread of a nut using laser triangulation. First, a specific image preprocessing procedure designed for a reflective laser in the internal thread of a nut is presented. The result of preprocessing critically affects the measurement accuracy of the proposed method. Thereafter, we propose a measurement algorithm designed for the appearance properties of the internal thread of a nut. Our method can operate in real time because the proposed algorithm can measure the pitch diameter of the internal thread of a nut in only a few steps and simple calculations.
Sloped-Gate Voltage Method for Improving Measurement of Poly-Si Nanowire FET in Aqueous Environment
(2013-05-02)
Chen, Chien-Hung
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Su, Yi-Jr
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Lin, Chih-Heng
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Liao, Tai-Shan
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Yang, Yuh-Shyong
Nanowire field-effect transistors are suited to. study the activity of biomolecules in bionanotechnology. The changes of biomolecules process are efficiently affected the charge at the nanowire surface; thus, the electrical characterization of NW-FET is Changed. Although NW-FET is a well-known device in bioapplications, however, the intrinsic electrical characterization of NW-FET effect, on real electrical measurement is not well studied. We present herein a novel measurement method to avoid errors in electrical characteristic of nanowire field-effect transistors. A physical model is developed to explore the effect of the leakage current, which is influenced by the charging effect of an equivalent capacitor in a NW-FET. We also present a sloped-gate voltage method to reduce the effect, of equivalent capacitor in air, liquid, and phosphate buffered solution. The application of the sloped gate voltage Method significantly increases the stability of electrical characterization measurements. This method can also be easily applied to biosensing experiments.
Surface composition and interactions of mobile charges with immobilized molecules on polycrystalline silicon nanowires
(2015-05-01)
Lin, Chih-Heng
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Feng, Mei-Huei
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Hwang, Chi-Hung
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Wu, Jennifer Yun-Shin
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Su, Ping-Chia
The polycrystalline silicon nanowire field-effect transistor (poly-SiNW FET) is one of the most sensitive sensors used in real-time and label-free biosensing applications. Its low power requirement, mass production potential, and integrability with electronic components make it a highly attractive device in the rapidly growing diagnostic research field. From the viewpoint of device physics, the charges in the vicinity of a nanowire (NW) surface modulate the electrical characteristics of the NW device. The charges can originate from surface molecules or an ionic solution, and their role in NW biosensing systems remains to be clarified. Determining their role is crucial for understanding the physical interactions of charges in a biosensing event and for the realization of NW-based biosensors. Therefore, using poly-SiNW FET, we investigated the interactions of the immobilized molecules on the NW surface with the mobile charges in solutions. We also investigated the interactions between the mobile charged polymers and the immobilized molecules on the NW surface, and we observed the effect of charge neutrality, originating from Coulomb charge-charge interactions, on the NW conductance. Finally, the isoelectric points between native and sulfated PSGL-1 peptides on the NW surface were identified. This study provides a physical understanding of the charge-charge interaction of mobile charges with immobilized charged molecules on a nanoscale surface and presents new opportunities for using charge-based detection in biological and chemical sensing applications. (C) 2015 Elsevier B.V. All rights reserved.
Tunable fiber confocal sensor with LED
(2015-01-01)
Weng, Chun-Jen
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Lan, Tzu-Hsien
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Hwang, Chi-Hung
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Chu, Nien-Nan
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Huang, Chien-Yao
A novel concept of confocal sensor based on focal lens is proposed to measure the displacement. The light source is a stabilized fiber coupled LED. A 1x2 graded-index multimode fiber optic coupler is used in this sensor. One port is a LED input port via SMA connector, another port is a LED output port connected to a reflective collimator and the other port is a reflective sensor port connected to a photo detector. The focusing sensor head is the cascade of a focal lens and a 20X objective lens. In this confocal displacement sensor, LED passes through a focal lens and an objective lens so that the LED beam focuses at a fixed focal point. A test target is placed after the objective lens. The displacement between the sensor head and a target can be measured quickly by detecting the reflective power according to the confocal principle. The long-term stability of LED is under 0.5%. The effective back focal length is varied from 5.67mm to 6.57mm by 0-290mA current driving so that the measuring range is about 0.9mm. The FWHM resolution of displacement is about 50 mu m. This sensor has the features of low cost, high stability, high precision and compact.