ENGLISH

2 卷 / 1 期

2 卷 / 1 期

華藝線上圖書館

Pages:

1-12

論文名稱

應用非監督性類神經網路於 SPOT衛星影像分類之研究

Title

Multispectral Classification of Spot Imagery Using Unsupervised Neural Network

作者

陳繼藩 , 徐守道 , 陳世旺

Author

C.F. Chen , S.D. Shyn , S. W. Chen

中文摘要

本研究嘗試結合非監督性類神經網路 (Unsupervised Artificial Neural Network) 及群集分析法 (Clustering ana1ysis) 來分類遙測影像。分類的過程分為兩個階段:第一階段以影像上的光譜資訊來進行細部的光譜分額,在此階段,本研究利用〝調適性共振理論〞(ART:Adaptive Resonance Theory) 類神經網路模型,對衛星影像進行非監督性分類。由於太細的分類,通常不合實際應用,因此光譜類別必須重組以求得組數較少的類別,因此在第二階段,本研究利用統計上的群集分析法,將第一階段所得之光譜類別重新聚集成較適合實際應用的類別。在實驗測試方面,先以模擬的衛星影像來測試本方法分類的效率及精確度,之後再以實際的 SPOT 衛星影像進行土地覆蓋/土地利用的自動化分類。測試結果顯示:本方法可於極短時間內完成分類,且精確度相較於ISOCLS 演算法亦有提高,實驗數據顯示,前者可達 96% 精確度,而後者為 94 %。

Abstract

This paper presents a two-stage approach to classify remotely sensed imagery. At the first stage, an unsupervised adaptive resonance theory neural network is invoked to perform a multi-spectral classification of satellite images. The outcome of this stage is a set of fine spectral classes. Since our goal is to obtain meaningful classes of the images the fine spec­tral classes are, at the second stage, reorganized into a small set of meaningful classes using a statistical clustering technique. The efficiency and accuracy of the proposed method is examined using a synthetic image. Afterwards, the proposed classifier is applied to a real SPOT image. Compared to another unsupervised classifier of ISOCLS, both classifiers have compatible processing times, while ours has achieved a better accuracy (96% for ours and 94% for ISOCLS).

關鍵字

類神經網路、非監督性分類、自適應共振理論(ART)

Keywords

Two-stage unsupervised classifier, Adaptive resonance theory neural networks, statistical clustering techniques

附件檔名

華芸線上圖書館

N / A

備註說明

199703-2-1-1-12

Pages:

13-29

論文名稱

利用四元樹法在 SPOT 影像上做林型分類之研究

Title

A Study on Quadtree Method to Forest Cover Classification on SPOT Imageries

作者

黃國楨 , 焦國模

Author

Kwo-Jern Hwang , Kwo-Mu Chiao

中文摘要

森林資源遙測包括林區調查、災害評估與森林管理等,其中以林型分類在森林資源遙測上為最首要工作。傳統分類林型大致使用監督性統計模式最大概似法則,而在這次研究中,為了要獲得更精確森林資源林型分佈狀況,我們提出一個簡單四元樹方法來辨識林型分佈。實驗中我們使用法國衛星(SPOT)做為材料,配合圖籍與數化地理資訊圖層套疊取樣以選取訓練樣區,再者用我們設計四元樹切割影像方法,切割臺灣大學實驗林衛星影像,直到切割每個子區域各灰度值非常均勻為止,最後將均勻各子區域選用數學式相關係數並配合權重數來計算分類林型,實驗結果顯示本研究所提出四元樹方法在林型分類是可行的且優於傳統統計模式最大概似分類法。

Abstract

Forest Remote Sensing consists of forest investigation、disaster estimation, and forest management etc.. One of the main purpose of remote sensing is to recognize the distribution of forest cover type. In this research, we propose a method to estimate the distribution on the remote sensing images with an eye to obtaining important information of forest resources for management purpose. In our work, French Satellite image (SPOT) is adopted as the material, and are integrated forest map and geographic information system as the overlay resampling. We devise the quadtree segmentation method segment the image of National Taiwan University Forest into uniform areas that satisfy the property of gray level homogeneity. T0 maximum likelihood classifier in conjunction with associating correlation value and weight loss are utilized to classify the distribution of forest. Experi­mental results reveal the feasibility of the proposed approach in forest cover classification.

關鍵字

四元樹、相關係數、權重數

Keywords

Quadtrees, Correlation, Weight Loss

附件檔名

華芸線上圖書館

N / A

備註說明

199703-2-1-13-29

Pages:

31-42

論文名稱

應用漸進取樣法於訓練區塊之選取與評估

Title

A Sequential Sampling Approach for Selecting and Evaluating Training Blocks

作者

邱祈榮

Author

Chyi-Rong Chiou

中文摘要

在大面積影像分類過程中,混合監督及非監督分類法的混合式分類法是有效且最被廣泛使用。於混合式分類法中,一般先選取一些較小的訓練區塊,來發展訓練統計值,以便進行監督分類。而在選取這些訓練區塊時,最常遇到的問題是該選取多少訓練區塊才足夠。本研究即針對此一問題,應用漸進取樣方法來做為選取訓練區塊及其過程之評估。以位於美國科羅拉多州的落磯山國家公園為本研究之試區,並以 100*100 ( 3*3 公里) 當作一訓練區塊。於取樣過程中,利用光譜、地形及生態等三項因素為評估之依據,並以族群及樣本間最大的累積分佈函數差異做為評估指標。結果顯示,於 5% 的最大差異限制下,23 個訓練區塊應足以代表整個國家公園。

Abstract

In this study, a sequential sampling was employed to statistically select and evaluate cluster training blocks. Training blocks, each 3 by 3 kilometers in size, were selected from the entire Rocky Mountain National Park. Spectral, topographic, and ecologic criteria were used to assess the adequacy of the sampling. The criterion to determine whether to stop or to continue the sampling was based on the maximum difference between the sample cumulative distribution function (CDF) and the population CDF. The results showed that for this particular data set, twenty-three blocks would be adequate to represent the entire Rocky Mountain National Park.

關鍵字

漸進取樣、訓練區塊、累積分佈函數

Keywords

Sequential Sampling, Training Block, Cumulative Distribution Function

附件檔名

華芸線上圖書館

N / A

備註說明

199703-2-1-31-42

Pages:

43-60

論文名稱

軌道修正及光線追蹤應用於SPOT 衛星影像正射化

Title

Generation of Digital Orthophoto from SPOT Images Using Orbit Correction and Ray Tracing

作者

張立雨 , 陳良健

Author

Li-Yu Chang , Liang-Chien Chen

中文摘要

於地理資訊系統中欲進行衛星影像與其他相關土地利用資料之整合中,衛 星影像必須與地圖座標系統一致。因此衛星影像之正射化幾何改正是必要的。 有別於傳統航測技術針對 SPOT 影像先進行光束法方位求解再進行正射化改 正,本文提出之方法乃利用載體參數配合少量控制點進行軌道修正後,再利用 光線追蹤法進行 SPOT 影像正射化。本文所提出之方法包括下列四個主要部 分: (1)利用少量地面控制點配合低階多項式針對衛星軌道進行修正,(2)於各控 制點相應軌道位置之殘餘誤差以最小二乘過濾法修正,(3)將修正後之衛星軌道 配合數值地形模型,以光線追蹤之方法求取每一像元所對應之地面座標,(4)將 前述之各離散點地面座標及影像灰度值以網格化內插以產生正射化之數位影 像。實驗結果顯示,在五個均勻分布之地面控制點條件下,其正射影像之檢核 點均方根誤差在各方向上均小於 0.6 像元。

Abstract

In combining satellite images with other landuse data in geographic information systems, the images must be coincided with the map coordinate system. Thus, the orthographic correction for satellite images is a necessity. Traditionally, the photogrammetric technique reconstructs the orbit parameters using bundle adjustment for SPOT satellite images followed by an orthographic correction procedure. We, from another point of view, proposed a scheme which corrects the on-board data by using small amount of ground control points (GCPs). Then, a ray tracing is applied to perform the orthographic correction. The proposed scheme includes four major components: (1) using a few GCPs to first fit the orbit parameter with low order polynomials, (2) performing least squares filtering to fine tune the orbit parameter according to the fitting residuals in the first step, (3) determing the corresponding ground location for each image pixel by ray tracing method using the filtered orbit parameter and a digital terrain model, and (4) grid gray value resampling for output orthoimage. Experimental results indicate that the generated orthoimages attain an accuracy better than 0.6 pixels when 5 GCPs are used.

關鍵字

軌道修正、光線追蹤、SPOT 衛星影像、正射化

Keywords

Orbit Correction, Ray Tracing, Spot Satellite Images, Orthographic Correction

附件檔名

華芸線上圖書館

N / A

備註說明

199703-2-1-43-60

Pages:

61-80

論文名稱

SPOT 衛星影像之輻射改正

Title

Radiometric Correction of SPOT Satellite Imagery

作者

劉建慧

Author

C. H. Liu

中文摘要

對於光學遙測而言,,地表物反射率之求取一直是最主要的課題。這是因為對於同一地表物,衛星量測灰度值影像隨感測器,太陽一觀測幾何,大氣和地形起伏等因素而不同。因此為了得到一合理與上述變因無關之物理量,使其恢復地表物之反射特性,必須輻射改正衛星灰度值影像,以求得地表反射率。 本文目的在輻射改正 SPOT衛星影像。首先研究地表反射特性與觀測一太陽幾何及大氣混濁度變化,包括提出最佳觀測角應定義為用以估計反照率之最佳觀測方向,且與地表物,太陽天頂角以及大氣之光學特性無關。其次發展一自影像本身求取反射率之大氣改正模式。在平地模式上,提出疊代法,以由影像本身自動疊代求取氣溶膠特性,以改正大氣中氣溶膠之影響。接著利用多時多角度影像,反演城市之雙向反射率分布函數( BRDF )。隨後建議以其BRDF 所求正規化反射率來建立光譜知識,用以自動化分類衛星影像。在山區模式上,由於疊代法不適用於山區,因此發展強制法用以改正影像之大氣效應。 研究結果顯示,檢證 Kimes 及Sellers1985 )所求得之最佳觀測角在不同混濁程度大氣中之適用性。在地表物反射率範圈 0.0-0.6 中,所反演之地表反射率 RMSE 可達 0.01一0.02 。正規化反射率建立光譜知識,此改進Wharton( 1987 )所提只適用於Landsat TM 之缺點,用以自動化分類衛星影像。山區反射率影像之求取,可減少地形效應。由非監督性分類結果顯示,改正前影像分類出不同照射程度,但同屬於一森林類;改正後影像則自動聚集為一類。改正後影像較原始影像,亦有助於研究地表變遷。

Abstract

Mapping of surface reflectance has been considered as a primary task for optical remote sensing, since the remotely sensed data is dependent of sensor characteristics, solar-viewing geometry, the atmosphere and topography for a given canopy. In order to retrieve its intrinsic reflective characteristics that is reasonablly indepent of the above external factors, determination of reflectance by using radiometric correction of satellite image is considered to be indispensable. The purpose of the dissertation is radiometric correction of SPOT satellite imagery. Firstly, the variability of surface reflective characteristics due to solar-viewing geometry and the atmospheric haziness is studied. We propose the optimal view angle should be defined as the direction that could be used to estimate the albedo and is insensitive to cover types, solar zenith angle and the optical properties of the atmosphere. Secondly, the atmospheric correction model of satellite image in horizontal surface is proposed. The aerosol characteristics are iteratively retrieved from the image itself. Thirdly, urban bidi­rectional reflectance distribution function (BRDF) is retrieved by using multi-temporal multiangle SPOT imageries. Fourth, we suggested the normalized reflectance determined by its intrinsic BRDF is much suitable than bidirectional reflectance factor (BRF) as the spectral knowledge. Finally, a robust algorithm for retrieving aerosol optical depth from satellite image over a mountainous area is proposed. The results show that the optimal view angle determined by Kimes and Sellers (1985) would be insensitive to the aerosol optical depth. The RMSE of derived surface reflectance in the horizontal surface is about 0.01-0.02 over reflectance range 0.0-0.6. Spectral knowledge determined from normalized reflectance is much suitable than that proposed by Wharton (1987). Determination of reflectance image can reduce the topo­graphic effect of image mountainous area. Without atmospheric correction, terrain related classes of forest class would be classified from unsupervised classification, whereas they automatically merge to one class after atmospheric correction. Radiometric corrected image is more suitable for change detection analysis than raw image.

關鍵字

輻射改正、大氣效應、反射率、數值地型模型

Keywords

radiometric correction, atmospheric effect, reflectance, digital terrain model

附件檔名

華芸線上圖書館

N / A

備註說明

199703-2-1-61-80

Pages:

81-90

論文名稱

以半自動影像匹配實施與解析製圖儀結合之空中三角測量

Title

Aerial Triangulation by Semi-automatic Image Matching for Analytical Plotters

作者

蔡奇璋 , 邱式鴻 , 王蜀嘉

Author

Chi-Chang Tsai , Shih-Hong Chio , Shue-Chia Wang

中文摘要

隨著自動化科技的進步,航測工業也以自動化為主要發展方向。影像匹配技術用於自動化空中三角點之量測研究已有多年,但至今尚未用於實際立體測圖生產作業上。近年來雖有攝影測量工作站之出現,但尚難完全取代現廣泛使用的解析測圖儀。在可見的未來,航測製圖仍會以人工在解析測圖儀上作業,尚難完全自動化。 雖然全自動化之空中三角測量尚無法實現,但是仍然可用部份由人工作業的半自動方式達到實用之目的。本文之目標即在發展一套可實用的半自動空中三角作業方法,以自動化影像匹配量取空中三角點以取代昂貴的轉點儀以及操作人員。同時著重在如何把人眼無法確認的空中三角點成果轉至解析製圖儀內,自動完成不需人工量測的絕對方位。以冀對整個航測自動化有所貢獻。

Abstract

In recent years, automatic Photogrammetry becomes a major goal for everyone in the Photogrammetric industry. The technique of image processing has been used in aerial triangulation measurement for years, but it has not yet been put on production lines. Although digital photogrammetric workstations have been brought up to the market for some years, they still can not replace analytical plotters because of the limitations in there functions. Therefore mapping will still be done manually on the analytic plotters in the near future. Although fully automatic aerial triangulation measurement has not yet been realized, some kinds of semi-automatic solutions are still possible. In this paper we developed a method for semi-automatic aerial triangulation measurement. The major concern of this development is production, not sophisticated matching theories, i.e. to put the image matching technique actually on production lines to replace the expensive point transfer instru­ments and experienced operators so that it is not jmerely a research topic in the labora­tory﹒We hope that the results of the semi-automatic aerial triangulation obtained here can contribute to the automation of Photogrammetry in the practice.

關鍵字

影像匹配、空中三角測量、解析製圖儀、自動化

Keywords

Image matching, Aerial triangulation, Analytica1 plotters, Autdmation

附件檔名

華芸線上圖書館

N / A

備註說明

199703-2-1-81-90

Pages:

91-102

論文名稱

應用 Hough 轉換加強連結點量測正確性之研究

Title

Robust Tie point Determination by Using Hough Transform

作者

徐百輝 , 曾義星

Author

Pei-Huei Hsu , Yi-Hsing Tseng

中文摘要

在數值攝影測量中進行相對方位計算之前,必須先量測立體影像對中連結點的位置。一般最常用的方法是以最小二乘匹配法求取立體影像對中的共軛點位置,但實際上常因為影像旋轉、曝光不均或者困地物高度不同產生遮蔽效應及陰影的影響,而造成匹配失敗。本文嘗試以 Hough 轉換偵測影像中房屋邊緣的直線段之位置,再求其交點當作屋角點。為了避免房屋陰影之影響,我們提出一判斷原則以偵測出真正的屋角點。本文最後以一實際之航測立體影像對來作實驗,以測試本文所提方法之可行性,所得結果證實此方法確實可以在有陰影平擾時取代最小二乘匹配法來量測正確的屋角點位置。

Abstract

In developing an automatic process to recover the relative orientation, tie points in each pair of stereo images should be identified. The least-square matching (LSM) has been widely used in the past few years but the fact that it tends to fail to match locally different images. Difficulties arise due to the influence of the image rotation and unequal expo­sures. The purpose of this study is to remedy the drawbacks of LSM. For identifying conju­gate image points, we detect the line segment of building roof using the Hough transform and compute the intersections of the lines to obtain the building corners .The result will be invariant with respect to the size and rotation of the image. In order to solve the occlusion problem, a simple criterion is proposed to match conjugate building corners. In order to test the practicability of this method, some experiments on a pair of real stereo image are processed with this method. The results are compared with the numbers obtained by using LSM. The comparisions show that this method is more robust to the effect of local changes in the images. We therefore conclude that this method can be a backup of LSM in image matching.

關鍵字

數值攝影測量、連結點

Keywords

Digital Photοgrammetry, Tie points

附件檔名

華芸線上圖書館

N / A

備註說明

199703-2-1-91-102

Pages:

103-112

論文名稱

「技術短文」航空攝影測量如何邁向資訊時代

Title

The Development of Photogrammetry Towards the Age of Information Science

作者

曾義星

Author

Yi-Hsing Tseng

中文摘要

地理資訊系統的興起代表人類已進入資訊時代,傳統靜態的地圖變成可動態查詢顯示甚至可分析演變的空間資訊系統。本文首先從航測與地理資訊系統近年來之研究與發展說明航測在面臨資訊時代所應走的方向,並探討航測在觀念與結構上的轉變,而後依航測之自動化從近程到遠程的發展目標:(1) DTM 與正射影像的生產;(2) 自動恢復影像方位;(3) 自動化立體測圖;及 (4) 影像辨識及判讀,逐一探討其發展狀況、可期應用目標及其困難之處。本文之結論是航測、遙測與 GIS 的整合將是時勢所趨,而其整合之關鍵則為地理資訊生產觀念的改變及航測的自動化。

Abstract

The booming applications of geographical information systems(GIS) demonstrates that we are in the age of information science. Traditional maps of many kind become spatial information systems in which one can dynamically query, display, analyze and manipulate spatial data. This paper tries to indicate the direction of photogrammetric field should be heading according to the developments of GIS and photogrammetric technologies, when the age of information science is coming. In addition, the conceptual and structural changes of photogrammetry will also be discussed. Along the track of automation in the field of photogrammetry, the goals and current condition of automation of (1) the generation of DTM and orthoimage, (2) automatic recovering image orientation, (3) automatic stereo mapping, and (4) image recognition and interpretation are examined. Photogrammetry, remote sensing and GIS have to be integrated in the future, and the key factors of integra­tion are the new concept of generating geographical data and the automation of photogrammetry.

關鍵字

航測、地理資訊系統、遙測

Keywords

Photogrammetry, GIS, Remote Sensing

附件檔名

華芸線上圖書館

N / A

備註說明

199703-2-1-103-112

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