ENGLISH

11卷/1期

11卷/1期

華藝線上圖書館

Pages:

1-12

論文名稱

空載光達點雲於OEM 自動生產與精度評估一使用ISPRS 測試資料為例

Title

Automated DEM Generation and Accuracy Assessment Using LiDAR Point Clouds -- A Case Study of ISPRS Test Data

作者

邵怡誠,陳良健

Author

Yi-Chen Shao,Liang-Chien Chen

中文摘要

光達測量是近年來新興的測量技術,主要應用於獲取物體的表面模型。光達系統可分為地面及空載兩大類,在空載光達的各項應用中,以自動生產數值高程模型為主要課題。本研究提出一套採用數學形態學方法的處理架構,藉由過濾地物點、保留的地面點產生數值高程模型。資料處理流程主要有四個:一是產生初始表面模型,二是濾除錯誤點,三是偵測地物區,四是篩選地面點。本研究使用ISPRS 公開的空載光達過濾測試資料,且依循ISPRS 的評估報告對本法成果進行定量的精度分析,同時提出個人操作經驗供作參考。實驗顯示,本研究方法可適用於各類不同地形特徵'且與數種具代表性的演算法相比較時,本法成果的總錯誤率是偏低的。

Abstract

Recently Light Delectation and Ranging (LiDAR) technology has developed to a new surveying method to acquire surface information. The system includes two types of terrestrial LiDAR and airborne LiDAR. The generation of digital terrain model (DEM) from airborne LiDAR point clouds is one of the most important applications in surveying and mapping. In this paper, we propose an automatic scheme based on object segmentation by Mathematical Morphology methods to filter out object points and use the reserving ground points to generate DEM. The scheme includes 4 main processing steps: (1) generation of initial surface model, (2) outlier removal, (3) object segmentation and (4) selecting ground points. The test data are released from ISPRS Commission III Working Group 3. We follow the quantitative assessment in ISPRS filter test to analyze our processing results. The experimental results and accuracy assessment are presented and show that most of the total errors are lower than the results of some representative filters.

關鍵字

空載光達、數值高程模型、數學形態學、過濾、精度評估

Keywords

airborne LiDAR, Digital Elevation Model (DEM), Morphology, Filtering,Accuracy Assessment

附件檔名

華芸線上圖書館

N / A

備註說明

200603-11-1-1-12

Pages:

13-26

論文名稱

植基於隱匿式馬可夫模式之多頻譜、多視角影像判釋

Title

Classification of Multiangular, Multispectral Imagery Using Hidden Markov Model

作者

左杰官,左豪官,Richard C. Olsen

Author

Brandt Tso,H. K. Tso,Richard C. Olsen

中文摘要

本研究以捷鳥2 號衛星於公元2003 年7 月13 日於美國加州Fresno 機場近郊所攝取之四角度多頻譜影像進行判釋實驗,判釋方法係基於隱匿式馬可夫模式(HMM)以設計監督式及非監督式分類方式並探討其基於多視角及多頻譜資訊之判釋效果,本研究於監督式判釋實驗上,係採用HMM 以模擬多頻譜、多視角影像間之關係,而於非監督式判釋實驗時,HMM則主要用於模擬空間之脈絡關係(Context),且係採用新設計之HMM觀測密度調整法(Observation density adjustment) 進行非監督判釋實驗,本研究發現多頻譜、多視角資訊確可增進影像之判釋精度,同時本研究發現基於HMM分類之精度要高於傳統方法如最大概似法及K-mean 分類之判釋精度。

Abstract

Four multispectral Images (MSI) were acquired upon various viewing angles by the Quickbird-2satellite in passing over airport neighboring fields nearby Fresno, California on July 13, 2003. Theseappear to be the very original, multiangular, multispectral, high spatial resolution images acquired fromspace. The classification experiments are based on the implementation of hidden Markov models (HMM)to design both supervised and unsupervised classification schemes to test the classification performancerelating to the angular and spectral information. For supervised classification, the HMM were applied tomodel the temporal dependencies between multiangular images, while for unsupervised classification, theHMM were adopted mainly to model the spatial dependencies (i.e. contextual information) using proposedobservation-density adjustment methodology. The experimental results reveal that the addition ofmultiangular information to MSI imagery significantly improves the accuracy of scene discrimination. Itis also concluded that HMM is a superior tool for dealing with multiangular, MSI data in comparing to thetraditional supervised maximum likelihood classifier and k-means clustering method.

關鍵字

監督式判釋、非監督式判釋、隱匿式馬可夫、多頻譜、多視角影像

Keywords

supervised, unsupervised, classification, HMM, MSI, multiangular

附件檔名

華芸線上圖書館

N / A

備註說明

200603-11-1-13-26

Pages:

27-38

論文名稱

應用抽穗期多光譜航照影像預估水稻產量之研究

Title

Rice Yield Prediction Using Multispectral Airborne

作者

章國威,王淑姿,申雍,羅正宗, 黃鼎名,蔡和霖

Author

K. W. Chang,S. Z. Wang, Y.Shen,J. C. Lo,D. M. Huang,H. L. Tsay

中文摘要

本研究應用美國NASA 1999 年成功研發的MODIS 影像作為研究材料,利用影像差異法挑選出適用於監測乾旱之MODIS 影像波段為第22熱感應波段。應用熱感應波段及其他波段之組合找尋出適合應用於偵測乾旱之指標如常態化熱指標(normalize thermal index, NTI) 、常態化差異水指標(normalized difference water index, NDWI)、常態化差異植生指標(normalized difference vegetation index,NDVI)及乾旱指標(drought index, DI),探討各式指標於乾旱之特性及其全年間之變化情形。本研究更利用多元迴歸分析找出對於累積30天雨量資料具有相關之乾旱指標變數,並將其整合成為利用MODIS影像應用於監測台灣地區之乾濕指標(drought-wet index, DWI),其效果可即時準確的偵測出台灣乾旱及潮濕的分布地點,因此未來將使乾早預警監測系統提供更完善之乾旱監測模式,以供管理單位之決策參考。

Abstract

In this study, a 4.8-ha ground truth site has been established. Within the site, several rice yield scenarios were produced by using combinations of rice varieties, nitrogen rate and drought treatments. Multispectral images by VCDi from ITRC were taken at booting stages of first rice crop season of 2004. Rice yield estimation models, using band ratios of either reflectance or radiance at green, red and infrared band (NIRJRED, NIR/GRN), were derived using ground truth data collected during1999-2002. Yields predicted from image were then compared with yield map measured at 10m x 10mmesh. Results indicated that using airborne multispectral images at booting stage to predicted rice yield was practicable. The prediction accuracy may be improved if better atmospheric correction method were used.

關鍵字

水稻(Oryza sativa L.)、特徵光譜、產量推估、遙測模式

Keywords

Rice (Oryza sativa L.), Characteristic spectrum, Yield estimation, Remote sensing model.

附件檔名

華芸線上圖書館

N / A

備註說明

200603-11-1-27-38

Pages:

39-58

論文名稱

MODIS 影像應用於台灣乾旱監測指標之建立

Title

Establish on MODIS Image into Drought MonitoringModel in Taiwan

作者

鐘玉建,陳朝圳,奚珍妮,劉士銘

Author

Yuh-Lurng Chung, Chaur-Tzuhn Chen,Chen-Ni His,Shih-Ming Liu

中文摘要

本研究應用美國NASA 1999 年成功研發的MODIS 影像作為研究材料,利用影像差異法挑選出適用於監測乾旱之MODIS 影像波段為第22熱感應波段。應用熱感應波段及其他波段之組合找尋出適合應用於偵測乾旱之指標如常態化熱指標(normalize thermal index, NTI) 、常態化差異水指標(normalized difference water index, NDWI)、常態化差異植生指標(normalized difference vegetation index,NDVI)及乾旱指標(drought index, DI),探討各式指標於乾旱之特性及其全年間之變化情形。本研究更利用多元迴歸分析找出對於累積30天雨量資料具有相關之乾旱指標變數,並將其整合成為利用MODIS影像應用於監測台灣地區之乾濕指標(drought-wet index,DWI),其效果可即時準確的偵測出台灣乾旱及潮濕的分布地點,因此未來將使乾早預警監測系統提供更完善之乾旱監測模式,以供管理單位之決策參考。

Abstract

Drought period, in general, the water resource for irrigation must transfer to civilization use, and compel the farmland to fallow. Therefore the water resource arrangement is gradually important in drought management in Taiwan. MODIS image which announced from USA NASA was used in this study, and applying image differencing method to extract thermal band of No.22 was the most useful for drought warning system. Use thermal band of No.22 combination with other bands of MODIS to calculate the monthly drought indicator, such as NTI, NDVI, NDWI, and DI, and taken variation analysis with these indicators in Taiwan. At this study applying multiple regression models to find out the related drought indexes with accumulate rainfall within 30 days, then integrated them to establish the drought-wet index (DWI). Examining DWI with the experimental data, the result shows that it is feasible to apply in drought monitoring in Taiwan. Therefore the DWI could promote the previous model in drought warning system and provide the manager the other information in decision making.

關鍵字

地理資訊系統、遙感探測、乾濕指標、多元迴歸

Keywords

Geographic Information System (GIS), Remote Sensing (RS), drought-wet index (DWI), multiple regression model

附件檔名

華芸線上圖書館

N / A

備註說明

200603-11-1-39-58

Pages:

59-68

論文名稱

以ASTER立體像對產製數值覆蓋模型之精度研究

Title

On the DSM Generation with ASTER Stereo Pairs

作者

施介嵐,史天元

Author

Chieh-Lang Shih,Tian-Yuan Shih

中文摘要

ASTER感測器之第三光譜波段使用推掃式立體成像系統,有別於其他採用本體旋轉組成同軌或跨軌立體成像模式之衛星;並且具有高B/H值,有利於數值高程模型的產製。ASTER 影像空間解析度15公尺,預估相對數值高程之精度約為十至三十公尺。本研究採用九份二山地區一幅ASTER影像,取其第三波段之立體像對產製數值高程模型,並與已知之數值高程模型進行比較,藉以評估其產製數值高程模型之精度。由測試區精度評估結果可發現當影像因雲等外在因素或匹配失敗地區的影響下,相對與絕對DSM與以航空攝影測量產製之參考數值高程模型相較,高程較差均方根值最大可達±414m;惟當無上述等影響下絕對DSM高程較差均方根值僅±11.87m。

Abstract

The third band of ASTER sensor provides along track stereo capability. Two images are collected in this band and one looking nadir, one looking backward. Based on the height-base ratio and the 15 meters spatial resolution of the ASTER sensor, the error of the relative DSM generated with the ASTER stereo-pair is expected to range from 10 meter to 30 meters. This study investigates the DEM accuracy with one ASTER scene in the Jeou-Fen-Erh-San area. It is found that the standard deviation is ±11.87m for areas without clouds or other unfavorable factors.

關鍵字

推掃式、同軌、跨軌

Keywords

Push-broom、along-track、across-track

附件檔名

華芸線上圖書館

N / A

備註說明

200603-11-1-59-68

Pages:

69-79

論文名稱

以數值地形圖和GIS資料計算都會區航照像片外方位參數之實用策略

Title

A Practical Strategy of Calculating Exterior Orientation of Urban Aerial Photos by Digital Map and GIS Data

作者

許志彰,廖揚清

Author

Chih-Chang Hsu,Yang-Cheng Liao

中文摘要

都會區新舊建物替換的頻率高,因此地圖更新的需求也相對較高。使用航空攝影測量進行地圖更新的首要工作就是求算像片的外方位參數。因此本研究試圖利用舊有的數值地形圖和地理資訊系統的資料來解算像片的外方位參數。選取能夠明顯辨識的房屋角點代替航測標,則可以免去外業控制測量的程序,雖然屋角點的坐標精度不如以全球定位系統衛星測量得到的航測標,但大量的人工建物屋角點如同大量的地面控制點,均勻分佈在整張影像上,提供多於航測標數倍的觀測量,不僅可降低航測製圖的成本,也能夠提升成果的可靠度,彌補房屋角點坐標精度的不足。為了測試本研究提出的方法是否能夠有效應用於台灣都會區的局部地圖更新,自原航照影像中選取了數個子影像,分別針對不同的屋頂面類型進行實驗與分析,包含平屋頂、山形屋頂和女兒牆屋頂。經實驗證明,利用舊有的數值地形圖和地理資訊系統資料所求算得到像片外方位參數,成果和精度都比直接人工單像量測的成果更接近解析製圖儀的成果,且能滿足1/1000 地形圖的製圖規範。

Abstract

The large-scale maps of built-up area are of special interest if they are to be revised or supplemented with new themes. The very first procedure for map revision is obtaining the exterior orientation. In this research, database information, including a digital map and GIS data, is used for exterior orientation. It would save times using building's comers instead of the control points. Although the accuracy of the building's comers could not be as good as those control points, the uniform-located comers would provide a great quantity of observations which could hopefully increase the reliability. To see if the applied method would work efficiently, several sub-images are abstracted from the original aerial image over urban area, including rectangular buildings with plat roofs, gable roofs and roofs with parapets. The result shows that it is feasible to find exterior orientation by existing digital map and GIS data and would suffice the required accuracy for local revision over 1/1000 map, which is stipulated under 10% of the complement coordinates would be llowed to deviate 20cm exceedingly corresponding to the aero-triangulation points.

關鍵字

數值地形圖、局部更新、機率鬆弛法、外方位參數、GIS資料

Keywords

digital map, local revision, probabilistic relaxation, exterior orientation

附件檔名

華芸線上圖書館

N / A

備註說明

200603-11-1-69-79

Pages:

81-92

論文名稱

滅點偵測之研究一基於θ-直方圖統計分析法

Title

A Study of Vanishing Point Detection-Based on θ-Histogram Analysis

作者

王幰彰,廖揚清

Author

Hsien-Chang Wang,Yang-Cheng Liao

中文摘要

本文提出基於θ-直方圖(θ-histogram)統計分析的滅點偵測(vanishing point detection)方法。此方法可適用於攝影時任一旋轉角不為零度或接近零度所拍攝的近景建物影像滅點位置偵測,不需要另外的已知條件及人工介入。經實驗證明,六幅室內模型影像利用本文之方法偵測滅點位置推算出的物空間長度RMSE值平均為±0.0041m,相對精度約達1/48~1/21;室外的實際建物影像,推算的物空間長度RMSE 值為±0.161m,相對精度約為1/64~1/27。此方法在加入以驗後方差估計原理導出的選擇權迭代法(李德仁,1992)後,即使用來計算滅點位置的直線有約13%不正確,推算物空間長度的RMSE值也能達到±0.166m,相對精度約為1/62~1/28,相當程度地確保了此法滅點偵測成果的可靠度。

Abstract

Using vanishing point to estimate orientation parameters does not need control point's information. It is applied for the object reconstruction, navigation of autonomous vehicles or robots, camera calibration and length measurement. This research present a method of vanishing point detection based on θ-histogram analysis. It is suitable for close-range building image and without manual interference. If orientation parameters have known can infer object length on single image. For criterion of experimentation result, we compare inferential length with real length and compute RMSE. Average RMSE of using our method in the six model images is ±0.0041m (relative accuracy is 1/48~1/21). RMSE of using our method in a real building image is ±0.0161m (relative accuracy is 1/64~1/27). Even if in the set of lines for vanishing point detection has 13% error, RMSE still can achieve ±0.166 m ( relative accuracy is 1/62~1/28 ). This result shows that our vanishing point detection method is robust.

關鍵字

滅點偵測、θ-直方圓、近景攝影測量

Keywords

Vanishing point detection, θ-histogram, Close-range photogrammetry

附件檔名

華芸線上圖書館

N / A

備註說明

200603-11-1-81-92

Pages:

93-109

論文名稱

小波轉換應用於高光譜影像光譜特徵萃取之研究

Title

Spectral Feature Extraction of Hyperspectral Images Using Wavelet Transform

作者

徐百輝,曾義星,宮鵬

Author

Pai-Hui Hsu,Yi-Hsing Tseng, Peng Gong

中文摘要

成像光譜儀所擷取的高光譜影像具有豐富且細緻的地物光譜資訊,此特性對於提升地物辨識能力及土地使用分類精度將有所助益。然而若以傳統的統計分類方法對高光譜影像進行分類時,其高維度的特性要求必須有大量的訓練樣本數目,同時大批的資料量亦降低了計算效率,分類精度也沒有顯著地提升。主要的問題在於當統計方法應用於高維度資料時所產生的「維度詛咒」現象。為了解決這個問題,本研究著重在光譜資料維度的降低,特徵萃取即為降低資料維度的一種方式,其基本觀念為去除較不重要的光譜資訊,只保留有用的特徵以降低高光譜資料的維度。本研究主要提出數種以小波理論為基礎的特徵萃取方法,以獲得對高光譜影像分類有用之光譜特徵。小波轉換為新一代的數學分析工具,其多層解析度及時不變的特性,使得其具有偵測局部訊號結構的能力。首先,我們先對高光譜影像進行離散小波或小波包轉換以獲得一組小波係數,之後再根據所設計的判斷法則選出有利於分類的特徵。因為特徵選取時係在維度較低的子空間中進行,因此有限樣本數目及「維度詛咒」等問題皆可以獲得有效的解決。本研究以兩組高光譜資料來測試所提小波轉換應用於光譜特徵萃取之有效性。實驗結果顯示以小波理論所萃取出的光譜特徵確實可以有效降低高光譜影像的資料維度,同時保持影像分類之精度。

Abstract

The rich and detailed spectral information provided by hyperspectral images can be used to identify and quantify a large range of surface materials which cannot be identified by ultispectral images. However, the classification methods that have been successfully applied to multispectral data in the past are not as effective as for hyperspectral data. The main problem is that the training data set does not increase corresponding to the increase of dimensionality of hyperspectral data. Actually, the problem of the "curse of dimensionality" emerges when a statistical classification method applied to hyperspectral data. A simpler, but sometimes very effective way of dealing with hyperspectral data is to reduce the number of dimensionality. This can be done by feature extraction that a small number of salient features are extracted from the hyperspectral data when confronted with a limited set of training samples. In this study, several methods based on the wavelet transforms are developed to extract useful features for classification. Firstly, wavelet or wavelet packet transforms are implemented on the hyperspectral images and a sequence of wavelet coefficients is produced. Then, a simple feature selection procedure associated with a criterion is used to select the effective features for classification. Because the wavelet-based feature extraction optimizes the criterion in a lower dimensional space, the problems of limited training sample size and the curse of dimensionality can be avoided. Finally, two AVIRIS data sets are used to test the performance of the proposed wavelet-based methods. The experiment results show that the wavelet-based methods perform well for dimensionality reduction and also be effective for classification.

關鍵字

高光譜影像、特徵萃取、小波轉換

Keywords

Hyperspectral Images, Feature Extraction, Wavelet Transform

附件檔名

華芸線上圖書館

N / A

備註說明

200603-11-1-93-109

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