2007.12
About Instruments Today No. 161
Hyperspectral Imager
Hyperspectral Image Analysis for Mapping Invasive Plant Species [ 下載 PDF ]
Fuan Tsai, En-Kai Lin
Hyperspectral remote sensing images provide more complete and detailed spectral information about ground coverage and have a great potential for more sophisticated applications. However, the large data volume and high dimensionality of hyperspectral data can cause substantial impact to its applications. Principal component analysis is a common technique used for feature extraction and reduction in remote sensing image analysis, but it may overlook subtle but useful information when applied to hyperspectral images. This research developed a spectrally segmented principal component analysis scheme that can not only reduce the dimensionality of a hyperspectral image but also extract critical spectral features helpful in discriminating different vegetation types. The developed methodology was applied to the analysis of an EO-1 Hyperion hyperspectral image to determine the status of an invasive plant species (Leucaena leucocephala) in southern Taiwan.
The Hyperspectral Imagers — ISIS & FUHSI [ 下載 PDF ]
Long-Jeng Lee
The two homemade pushbroom hyperspectral imagers, named as ISIS (intelligent spectral imager system) and FUHSI (farming-use hyperspectral imager), adopted on different carriers and at different altitudes have been developed. The development and optical characteristics of two hyperspectral imagers will be introduced. Case studies of applications of ISIS on the wetland along the coast and precision farming are presented.
Applications of Hyperspectral Imager in Precision Agriculture [ 下載 PDF ]
Shu-Zi Wang, Chen-Chih Wu, Yuan Shen
Hyperspectral imager provides nearly continuous reflectance spectrum of ground surface for large areas. This makes it particularly suitable for remote sensing studies to delineate minor changes in reflectance spectrum, such as applications in precision agriculture. The hyperspectral imager, ISIS, made by ITRC of NARL supplied the needed image data for researchers in Taiwan to develop the technologies for precision agriculture. In this study, the applications of hyperspectral imager on precision agriculture were illustrated by obtaining the spatial distribution of yield, important growth characteristics, and nitrogen status in a precision rice cultivation site, located in Taichung county, of NCHU.
Application of ISIS Hyperspectral Optical Remote Sensing Imagery on Monitoring the Water Quality of Tseng-Wen Reservoir [ 下載 PDF ]
Cheng-Chien Liu, Chih-Hua Chang, Hua-Yu Hsu, Chi-Chen Tan, Ching-Gung Wen
Monitoring the water quality of a reservoir is one crucial task closely related to the basic requirement of human being. The ISIS hyperspectral image of Tseng-Wen Reservoir was taken by ITRC (Instrument Technology Research Center) from an airborne platform. In the meantime, the handheld radiometer was employed to measure the spectral reflectance on the water surface. The water samples were taken and brought into the laboratory to analyze the inherent optical properties and various parameters of water quality, following the standard procedure of operation. These results were used as the ground truth for validating the retrievals from ISIS imagery later on. The ISIS image was geo-referenced and converted to the map of surface reflectance. The latest progress in hyperspectral data inversion, namely GA-SA approach, was employed to process the ISIS-derived surface reflectance at seven sites. The retrievals of IOPs and water quality parameters were then compared to the earlier results obtained form the laboratory analysis. This research enables us to evaluate and discuss the feasibility of monitoring the water quality of a reservoir using the ISIS hyperspectral optical imagery.
"The Design and Study of Combining ESPI with Time-Stepped Quadrature Phase Shifting and (5,1) Phase Shifting Technology" [ 下載 PDF ]
Shu-Sheng Lee, Han-Wei Wang, Eddie Tseng, Ii-Hung Hsu, Chih-Kung Lee
Electronic speckle pattern interferometry (ESPI) is a very common metrology for nondestructive testing. The resolution of ESPI is getting better as the optical image technology and the electric components improving. It is gradually applied to small specimen surface measurement within the microscopic system operating conditions. The major issue of ESPI is how to improve the measurement range. In order to solve this problem, the time-stepped quadrature phase shifting method was adopted as the phase unwrapping method in this research. For comparison, (5,1) phase shifting technology was also integrated to the ESPI system as the phase unwrapping method. It was proved that the timestepped quadrature phase shifting method built-in ESPI could successfully reconstructed the deformation of object which could not be solved by (5,1) phase shifting technology.
Development and Applications of UV Proximity Printing for Micro-Optical Elements [ 下載 PDF ]
Hsiharng Yang, Ching-Kong Chao, Tsung-Hung Lin
This paper describes the UV proximity printing method to fabricate micro-optical elements, such as microlens array, micro-waveguides and high numerical aperture microlens. The micro-optical structures were made by applying a printing gap in UV exposure, which utilizes the UV light wavelength diffraction to deflect away from the aperture edges and produces a certain exposure on the photoresist material outside the aperture edges. Several microlens materials can be fabricated from various photoresist properties. The experimental results showed that the optical components could be formed automatically when a particular printing gap existing. The UV proximity printing method is an innovative method for fabricating micro-optical components. Thus, the further microoptical production using this technology is anticipated.
Optimal Design of Multi-Sphere Reflection Mirror for YAG Laser in Thermal Fracture Cutting Technology [ 下載 PDF ]
Wen-Hong Wu, Kuo-Cheng Huang, Shih-Chu Huang
The thermal fracture cutting technology for brittle materials has become the crucial technology for LCD glass substrate cutting to meet the low residual thermal stresses requirement. The reflection mirrors were involved when the YAG laser played the role of a heat source in the glass thermal fracture cutting technology so as to overcome the low absorption rate of near IR for glass. This article presents an ideal energy distribution for improving the cutting speed of thin plane glass. And a novel reflection mirror with multi-sphere surface was developed to regulate the laser energy distribution. Furthermore, the shape of multi-sphere surface was optimized by Taguchi method so as to meet the ideal energy distribution.
The Effects of Image Pixels on the Uncertainty of TEM Measurement [ 下載 PDF ]
Wei-Lin Wang, Yu-Feng Ko, Hong-Yuan Chu
The uncertainty of Transmission Electron Microscopy (TEM) measurement is affected by the stability of acceleration voltage, defocus, lens aberration, repeatability and reproducibility...etc. The current work evaluates that how the pixels of image obtained through charge coupling device and related software influence the uncertainty of TEM measurement. There are three major measuring tools, including line ROI tool, line profile tool, and line tool in the software for TEM measurement. The results of evaluation reveal that line profile tool provides the smallest uncertainty in measurement. By the comparison of measurements in real space and reciprocal space, both can achieve an approximate result for the reduction of uncertainty.
First-Principles Analysis of Co/Pt Multilayers [ 下載 PDF ]
Hung-Pin Wang, Chyun-Hao Su, Hao Ouyang
The atomic arrangements and magnetic property of interface in Co/Pt multilayers were studied according to the analysis of high resolution transmission electron microscope (HRTEM) and the local density functional approximation (LDA). By detailed simulations of atomic microstructure mapped onto high resolution transmission electron microscope (HRTEM) image patterns, both the results from experiments and simulations are compared then the atomic positions were identified. The detailed atomic arrangements around the interface can be fed into the first-principles calculations to study the electronic structure.
Maskless Mesoscale Materials Deposition Technology for Electronics Applications [ 下載 PDF ]
Hsueh-Yu Hsiang [Translate]
The continual drive for smaller, more powerful and economic electronic systems, has led to the development of a new manufacturing technology, maskless mesoscale materials deposition (M3D). As a CAD driven, additive manufacturing process, M3D provides significant environmental benefits and reduced processing requirements, eliminating the waste associated with traditional subtractive (e.g. mask and etch) processes. M3D can also precisely deposit materials on non-planar substrates. With no physical contact with the substrate by any portion of the tool other than the deposition stream, conformal writing is easily achieved. Other benefits include time compression and increased Manufacturing Agility, lower costs, and better product designs. This paper will detail the benefits of M3D technology in creating mesoscale features for electronics assembly and semiconductor packaging applications.
