ENGLISH

7卷/1期

7卷/1期

華藝線上圖書館

Pages:

53-76

論文名稱

使用三像法衛星雷達差分干涉測量九二一大地震災區災變前後高程變動之初步測試成果分析

Title

Analysis on Preliminary Test Results of Satellite D­InSAR-Three Pass Method-for Determining a DDM in Mid-Taiwan Caused by the Chi-Chi Earthquake

作者

蔡展榮 , 呂建興

Author

Jaan-Rong Tsay , Chien-Hsiang Lu

中文摘要

本文使用 1999 年九二一大地震前後(1月21 日、5月6日、9月23日、10月28日)共四張臺灣中部地區之二號歐洲雷達衛星 ERS 2 原始資料,配合三像法衛星雷達差分干涉測量臺灣九二一大地震災區災變前後高程變動量,分析計算步驟。檢視簡易理論模式推導分析可知:「如果合成口徑雷達干涉測量法InSAR能求定出數公尺等級的數值高程模型DEM精度,則其差分法D­InSAR 可以求定出數公釐等級的高程位移精度。」本文初步實驗測試結果顯示,如果有合宜(高同調性)的衛星雷達資料而且後續各項的資料處理恰當,則使用三像法和歐洲雷達衛星資料求定臺灣的平坦平原都會地區之數值位移模型 DDM 之精度具有達到數公分等級之潛力,但是,實務上,合宜的衛星雷達資料取得確實不易,而且即使取得合宜的資料,衛星雷達影像內的山林區,D-InSAR 不易成功。將三像法計算出的 DDM 和高精度衛星定位測量法 GPS 求定的地表高程位移成果做一比較,顯示共同區內兩者表示的位移趨勢一致,檢核點上的平均較差約 6cm 。

Abstract

In this paper, four European Radar Satellite (ERS-2) images acquired on January 21, May 6, September 23, and October 28, 1999, respectively, in mid-Taiwan are used to test the quality of a digital displacement model (DDM) determined by three pass method, a technology of differential interferometric synthetic aperture radar (D-InSAR). The terrain surface has an abrupt change during the event of Chi-Chi earthquake. Some basic theoretic aspects are firstly analyzed. It verifies that D-InSAR can provide a DDM with an accuracy of a few millimeters, if InSAR can create a digital elevation model (DEM) with an accuracy of a few meters. In general, the DDM show a vertical displacement vector field similar to the vertical displacement map determined by GPS. Inside the DDM, there are some GPS check points. They show that the mean difference of the displacement values estimated by satellite D-InSAR and the ones determined by GPS is about 6cm. They indicate that three-pass method seems to have a potential for detecting height surface deformation in plain area in Taiwan, if useful ERS data are processed properly. On the other hand, D-InSAR might fail to determine an accurate DDM in fluctuant areas with dense and high vegetation since the coherence is low there.

關鍵字

三像法、衛星、合成孔徑雷達差分干涉測量、數值位移模型、線性調頻

Keywords

three-pass method, satellite, differential interferometric SAR (D-InSAR), digital displacement model (DDM), chirp

附件檔名

華芸線上圖書館

N / A

備註說明

200203-7-1-53-76

Pages:

77-86

論文名稱

NDVI 與 SAVI 受土壤影響之研究

Title

A Study of Soil Effect to NDVI and SAVI

作者

劉建慧

Author

c. H. Liu

中文摘要

一個理想的植被指數應只與植被有關,而與土壤類別、溼度及亮度、太陽天頂角無關。如此,植被指數才能充分反映植被生長。本文使用線性混合模式,研究土壤對不同植被指數之影響。依據電腦模擬結果顯示,NDVI(normalized difference vegetation index)受土壤影響遠大於SAVI(soil adjusted vegetation index),此結果與學者研究相符(Huete, 1988)。為了充分描述土壤變異之影響,在經過 1000 次雜訊實驗後,SAVI 之平均最大容忍雜訊可達 29.0% 。最後結果也指出,在高土壤干擾環境或狀況下,SAVI 對於植物成長也較 NDVI 靈敏。

Abstract

An ideal vegetation index should depend upon vegetation only and independent to soil type, soil humidity and solar zenith angle. Information of vegetation growth may therefore be deduced from such a vegetation index. In this paper, linear mixture model is used to study the soil effect to different vegetation indices. It indicates that NDVI is greatly affected by soil effect than that of SAVI, similar to the finding by Huete (1988). SAVI can also tolerate maximum noise up to 29.0% after 1000 times of noise test. Results demonstrate that SAVI is more sensitive to vegetation growth than NDVI under the conditions of higher soil interference.

關鍵字

植被指數、土壤、反射率

Keywords

Vegetation index, Soil Reflectance

附件檔名

華芸線上圖書館

N / A

備註說明

200203-7-1-77-86

Pages:

1-14

論文名稱

含房屋之中華二號衛星影像幾何模擬及校正

Title

The geometric correction for the ROCSAT-2 high resolution satellite images

作者

陳允麾 , 陳良健

Author

Yun-Hui Chen , Liang-Chien Chen

中文摘要

本研究之重點是以考慮地表的地形變化、人工建築物存在和相互的遮蔽問題之高解析力衛星中華二號 (ROCSAT-2) 的影像正射化程序為主要工作。中華二號衛星影像是以推掃式(Pushbroom)的成像方式,故其正射化有別於航照像片。目前適用之衛星影像相關資料無法取得,故需以模擬資料來進行測試。 首先的工作就是模擬出中華二號衛星影像,這張影像必須是要考慮地表的地形變化、人工建築物的存在和相互的遮蔽問題。模擬衛星影像的程序是利用已經建構好之 ROCSAT-2 的軌道參數、星曆資料和 DSM(Digital Surface Model)以逆轉換模式 (Bottom-up) 來進行模擬。模擬影像所要填入的灰度值資訊則是利用經正射、鑲嵌後之數位航空影像來當基準,如此一來模擬的衛星影像才會和真實影像相近。 在模擬衛星影像的工作完成後,接下來就是要進行正射化的工作。在此階段中,以逆轉換模式來進行正射化的程序(所應用的資料是建構好的 ROCSAT-2 軌道參數、星曆資料和 DSM)。在完成正射化程序後的衛星影像,將可以修正在衛星影像上因為高差移位效應所呈現之傾斜人工建築物及地形至正確的影像位置上。

Abstract

The focus of this investigation is the geometric correction for the ROCSAT-2 high resolution satel­lite images. We correct satellite images using digital surface model (DSM) that includes building and terrain information. Unlike frame photography, where all pixels in the image are exposed simultaneously, each line of a ROCSAT-2 image is collected in a pushbroom fashion at a different instant of time. Due to unavailability of test data, we need to simulate a high resolution satellite image which considers that the terrain and the building may be hidden each other test. First of all, we developed a satellite-orbit-model for ROCSAT-2, including coordinate-transformation-model, satellite-fly-model, simulation-model and on-board-data-model, and then using a DSM to simu­late a high resolution satellite image by Bottom-up approach. In addition, the bases of the simulated image are orthorectified aerial images to minimize differences between the simulate image and the true image. The gray values for the walls of each building are assumed homogeneous. Once imaging simulation is completed, we use a satellite-orbit-model of ROCSAT-2 and DSM to orthorectify the simulated ROCSAT-2 satellite's images by Bottom-up method.

關鍵字

衛星中華二號、推掃式、正射化、數值地表模型

Keywords

ROCSAT-2, Pushbroom, orthorectify, DSM

附件檔名

華芸線上圖書館

N / A

備註說明

200203-7-1-1-14

Pages:

15-34

論文名稱

運用衛星雷達干涉測量法在臺灣地區求定數值高程模型之初步實驗成果和實務探討

Title

Preliminary Test Results and Practical Consider­ations on DEM Generation in Taiwan by Satellite SAR Interferometry

作者

蔡展榮 , 陳鴻緒

Author

Jaan-Rong Tsay , Hung-Hsu Chen

中文摘要

本文使用商用軟體 Vexcel 3dSAR 的合成孔徑雷達資料處理系統 FOCUS/PHASE 與 ERS Tandem Mode 衛星雷達資料,以合成孔徑雷達干涉測量法(InSAR)求定實驗區(臺北縣都會區)的數值高程模型(DEM),說明和分析採用的衛星雷達資料處理計算步驟,並做一實務探討。將初步實驗產生之 DEM 與台北縣航測高精度參考 DEM 進行比較,共使用 84 個地面控制點,求得它們的平均高程差為 -0.11 公尺,均方差為 4.71 公尺。並取得約 12km × 10km 區域內共 93850 個共同格點,得兩者的高程差之均方根值(RMS)為23.73公尺,其中有 86% 之高程格點其高程差在±20 公尺內;將高程差在±20 公尺內之點位分佈與航測正射影像對照,可發現高程差與地表覆蓋物種類有著相關性:在建物密集的區域其高程差較大,約5至 20公尺,而在無建物或無植被或稀疏植被覆蓋之區域其高程差較小,約在 ±5 公尺之間。

Abstract

In this paper we describe and study the SAR (=synthetic aperture radar) processing steps adopted in our preliminary tests for generating a digital elevation model (DEM) in Taiwan by means of satellite SAR interferometry. We used two modules FOCUS and PHASE of the commercial software system "Vexcel 3dSAR Processing System" and ERS Tandem mode data to generate a DEM by the interferometric syn­thetic aperture radar (InSAR) approach. The generated DEM is compared with the high precision reference DEM determined by aerial photogrammetry with an average flight height of about 1600m in the same area of about 42km x 25km in Taipei. Altogether 84 ground control points are adopted. They show a mean and RMS (=root mean square) value of height differences of -0.11m and 4.71m, respectively. Moreover, there are altogether 93850 common height points in an area of about 12km x 10km. They indicate a RMS value of height differences of 23.73 meter. About 86% of all these points has the absolute height difference |dH| <20m. Comparing the distribution of these points with the aerial ortho image shows the correlation between the height difference and the land cover type. The absolute height difference is larger in the area of dense buildings, about 5-20 meter. In the near bare area of no buildings and less vegetation, the absolute height difference is smaller and less than 5 meter.

關鍵字

衛星、合成孔徑雷達、干涉測量法、數值高程模型

Keywords

Satellite, Synthetic Aperture Radar (SAR), Interferometry, Digital Elevation Model (DEM)

附件檔名

華芸線上圖書館

N / A

備註說明

200203-7-1-15-34

Pages:

35-52

論文名稱

利用航測與地理資訊系統技術調查阿里山針闊葉林自然保護區地形與林型分佈之研究

Title

Applications of Aerial Photogrammetry and GIS Techniques on Mapping the Forest Types and Terrain Characteristics of the Alishan Natural Reserve Area

作者

林金樹 , 管立豪

Author

Chinsu Lin , Li-Hao Kuan

中文摘要

本研究利用航測技術測繪阿里山針闊葉林自然保護區之林型分佈圖及數值地形模型資料,目的在瞭解阿里山針闊葉林自然保護區之植群資訊,以供保護區森林經營與遙測研究之應用。研究結果顯示,阿里山針闊葉林自然保護區之平均海拔高為2110公尺,平均坡度為23.4゜,全區50%林地面積的坡度高於平均坡度,整體的地形景觀則呈現由西北方向往東南方向逐漸爬升之走勢,全區具有多重的皺褶分佈,地形起伏變化很大。阿里山針闊葉林自然保護區內之優勢樹種有針葉樹類之檜木、鐵杉、松類、柳杉、台灣杉等以及闊葉樹等,這些植群多以混淆林的型態分佈其間;利用航測法共可將全區植群之分佈區劃為 16 種林型,其中以檜木類松類混淆林、檜木松類闊葉樹混淆林、檜木類鐵杉松類混淆林以及檜木類鐵杉松類闊葉樹混淆林等四種混淆林型為最大宗,合計約佔 92% 的保護區面積;阿里山針闊葉林自然保護區之林型在不同的海拔高、坡向及坡度等不同的地形條件下出現的林型豐富度有極顯著的差異。

Abstract

The Alishan natural reserve area, abbreviated as ANRA, locates in the middle-southern part of Taiwan. It has been choosing to be the study site for implementing serial remote sensing researches that focus on the long-term development monitoring of forest reserve area. This study is an essential one of the serial researches. It aims to mapping the distribution of vegetation types to supporting the research needs of remote sensing. After review the relative literatures and onsite checking survey, we made a photo interpretation key for mapping the forest types of ANRA. A digital elevation model of ANRA was also produced in this study by the means of digital photogrammetry for applying to analyze the terrain of the study site. The results show that the mean of the elevation and slope of ANRA is 2,110 meters and 23.4 degrees respectively, and there are about 50% of the site area whose slope is greater than the slope mean of the site. The terrain relief of ANRA goes up from the lower northwest to the higher southeast and covers with many folds around the whole site. The dominant species of ANRA are Chamaechyparis spp. Tsuga chinensis, Pinus spp., Cryptomeria japonica and Taiwania cryptomerioides, and other hardwood species. All of these species are mainly distributed in mixed types and rarely existed in pure types. There are 16 forest types that could be interpreted from the aerial photographs. And among all of the forest types, the HP (Hinoki-Pinus), HPH (Hinoki-Pinus-Hardwood), HTP (Hinoki-Tsuga-Pinus), and HTPH (Hinoki-Tsuga-Pinus-Hardwood) are the superior ones and they inhabit totally more than 92% of the site area. The richness of forest types (RFT) of the ANRA is significantly different at varying situations of the elevation, aspect and slope factors.

關鍵字

航測、地理資訊系統、阿里山自然保護區、林型、地形分析

Keywords

Aerial photogrammetry, GIS, Alishan natural reserve area (ANRA), Forest type, Terrain analysis

附件檔名

華芸線上圖書館

N / A

備註說明

200203-7-1-35-52

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