ENGLISH

6卷/3期

6卷/3期

華藝線上圖書館

Pages:

1-21

論文名稱

中華二號衛星影像幾何模擬及方位重建

Title

Image Geometric Simulation and Orientation Modeling for ROCSAT-2

作者

吳怡瑛 , 陳良健

Author

Yi-Ying Wu , Liang-Chien Chen

中文摘要

本研究之目的有二,(1)針對中華二號衛星所遙測得到的地表影像進行模擬,(2)開發幾何處理之模式。由於中華二號衛星尚未升空,為了建立衛星影像幾何改正模式之測試所需,參考中華二號衛星目前已公佈之規格,以已經正射、鑲嵌之數位航空影像配合數值地形模型(DTM)進行中華二號衛星之影像及星曆資料模擬。 為進行中華二號衛星之影像及星曆資料模擬,必須建立一衛星飛行成像模式。此模式可分為四部份:一為坐標轉換模式,目的在建立研究所需之坐標系統間彼此轉換關係。二為衛星飛行模式,目的在描述衛星飛行情形。三為衛星成像模式,目的在進行中華二號衛星影像及星曆資料模擬。四為星曆資料模式,目的在藉由誤差添加使得模擬資料更接近真實中華二號衛星飛行情形,而誤差將分系統誤差與隨機誤差添加在星曆資料中衛星位置與姿態上。 模擬資料產生後,以模擬之資料進行方位求解及定位。在單張影像部份,以星曆資料建立初始軌道,再在基本影像與模擬之影像上點選控制點以進行軌道修正後,使用最小二乘過濾模式進行精密軌道修正,再以檢核點進行定位檢核。實例測試結果顯示使用最小二乘過濾模式可以消除大部份系統誤差,但無法消除隨機誤差。在立體對部份,則二張影像在分別經過軌道修正後,透過前方交會以最小二乘過濾模式進行物空間三維坐標修正,最後以檢核點進行三維定位檢核。實例測試結果亦顯示使用最小二乘過濾模式可以消除大部份系統誤差,但無法消除隨機誤差。

Abstract

The objective of this investigation has two folds. One is to simulate ROCSAT-2 images and the other is to develop a applicable model for geometric correction to ROCSAT-2 images. We will use orthorectified aerial image and digital terrain model as referance data to perform imaging simulation. This is due to the unavailability of ROCSAT-2 image. For ROCSAT-2 image and on-board data simulation, we need to establish a satellite-orbit-model. This model can be divided to four parts. The first one is coordinate-transformation-model which transforms all coordinate systems in this investigation. The second one is satellite-f1y-model which describes the satel­lite orbit. The third one is simulation-model which simulates ROCSAT-2 image and on-board data. The fourth one is on-board-data-model which simulates on- board data by assuming ROCSAT-2 flying case and adding errors to satellite position and attitude data. The errors include systematic errors and random errors. We compute orientation parameters and position using simulation data. In single image case, we use on-board data to establish initial orbit and correct the orbit with ground control points. Then we use least squares filtering to fine tune the orbit and perform the validation. In stereo images case, we adjust 3-D position in object space by using least squares filtering after correcting orbits of two images. Then the validation is performed. Experimental results indicate that the systematic errors may be mostly compensated while the random errors consistently influence the positioning accuracy.

關鍵字

中華二號衛星、幾何模擬、方位求解、三維定位

Keywords

ROCSAT-2, image geometric simulation, orientation modeling, 3-D positioning

附件檔名

華芸線上圖書館

N / A

備註說明

200109-6-3-1-21

Pages:

23-35

論文名稱

數位相機檢定之自動化

Title

Automation of Digital Camera Calibration

作者

劉虹妤 , 曾義星 , 王聖鐸

Author

Hong-Yu Liu , Yi-Hsing Tseng , Sendo Wang

中文摘要

應用於近景攝影測量之相機依其量測之穩定性,可分為量測性及非量測性相機。由於數位相機的發展逐漸取代底片式相機,配合電腦視覺使近景攝影測量朝向自動化發展。目前市面上之數位相機屬於非量測性相機,此種相機要應用在近景攝影測量上必須進行相機率定的工作,其率定方式以自率光束法較為合適。此率定方法利用三維空間均勻分佈的未知座標標點,以多張相片的方式進行率定同時解算內外方位。其主要缺點是影像坐標之量測工作繁重,為解決這項問題,本文設計一種可供自動辨識及定位的人工標點及自動量測之程序,以達到相機率定之自動化,即整合自動辨識及量測功能於相機率定系統中。實驗結果顯示標點辨識及定位之成功率達70%以上,加上少量人力輔助的修正可輕易達90%以上的成功率,將此辨識量測成果應用於數位向機率定及定位,其定位結果之標準偏差可輕易達到公分以下之精度。

Abstract

Digital cameras are getting widely used due to their operation conveniences and real-time processing capabilities. Although digital cameras have been considered suitable to photogrammetric tasks, their metric characteristics are not clear and stable as traditional metric cameras. A real-time on-the-job calibration is therefore, required before a digital camera can be applied for a photogrammetric task. The techniq ue of self­calibration is considered an effective means for digital camera calibration, but a large amount of image measurements are required. To solve this problem, we designed a new text-coded target and proposed an automatic process to detect, position, and identify the targets. Automatic camera calibration can be achieved by integrating this automatic measuring process and bundle adjustment computation. The experimental results are encouraging and optimally show the feasibility of the proposed method.

關鍵字

近景攝影測量、相機率定、數位相機、自動化

Keywords

Close-range Photogrammetry, Camera Calibration, Digital Camera, Automation

附件檔名

華芸線上圖書館

N / A

備註說明

200109-6-3-23-35

Pages:

37-55

論文名稱

半自動化建物萃取之建物模型建置與操作

Title

Building Model Establishment and Operation for Semi-Automatic Building Extraction

作者

林文棋 , 曾義星 , 王聖鐸

Author

Winch Lin , Yi-Hsing Tseng , Sendo Wang

中文摘要

三維城市空間資訊系統(3D City Spatia1 Information System)更能展現城市的空間面貌及性質,是為目前研發的趨勢。而建立三維城市空間資訊系統最迫切的工作是建物資訊的收集,本研究提出一套半自動化 CSG 模型式建物萃取法以萃取建物之三維資訊,並闡述如何以 CSG 理論建置建物模型及說明相關的操作,以配合半自動化的模型式建物萃取理論。首先分析整理常見的建物類型,依據 CSG 理論據以建置單一類元件及複合類元件兩種類型的房屋模型庫,如此可依照 CSG 之樹狀組合原則建構出完整的複雜建物模型。每一個建物元件均附帶有一組模型參數,操作員在選取適當的元件後,可透過參數的更動使模型的外觀及姿態與影像中的房屋外形套合。本文將介紹在套合程序中相關的元件模型操作方法,透過 CSG 模型的建置與實際操作,以實驗證明本文所提方法之可行性,作為未來建置半自動化模型式建物萃取實際應用系統的藍本。

Abstract

Developing a 3D city spatial information system to vividly model a city is currently an intensive research area in the field of digital photogrammetry. In this study area, extracting building information is the most important work. This study proposed a semi-automatic CSG model-based building extraction method to acquire precise, reliable and complete 3D data of buildings. In this paper how to apply CSG theory for building models and related model operations are illustrated, so that we can employ it in the semi-automatic model-based building extraction. To investigate how the CSG model fits real buildings we analyzed and classified the characteristics of common building shapes. Based on the investigation, a CSG building model base containing simple and compound primitives is proposed. By combining the primitives we can con­struct complex building models. Each building primitive will be associated with a set of parameters that can be modified to perform model-image fitting. The methods and tests of model operation for model-image fitting will be introduced. This study draws a blueprint for semi-automatic building extraction.

關鍵字

數值攝影測量、建物萃取、建構式立體幾何 (CSG)、模型表示法

Keywords

Digital photogrammetry, Building extraction, Constructive solid geometry (CSG), Model representation

附件檔名

華芸線上圖書館

N / A

備註說明

200109-6-3-37-55

Pages:

57-73

論文名稱

最小二乘 CSG 模型與影像最佳套合

Title

Least-squares CSG Model-image Fitting

作者

周宏達 , 曾義星 , 王聖鐸

Author

Hung-Ta Chou , Yi-Hsing Tseng , Sendo Wang

中文摘要

半自動化模型式建物萃取法是目前航空攝影測量主要的研究方向,其中模型與影像的最佳套合演算法則是整個流程的關鍵。本文設計了兩種常見的房屋模型基本元件(primitive),依據建構實體幾何 (Constructive Solid Geometry, CSG)的理論可將基本元件加以組合,以描述複雜的房屋模型。每個元件都具有一組形狀參數與姿態參數,藉由調整元件的模型參數可以改變元件的外觀、大小以及在物空間中的位置與姿態。本文所提出之最佳套合法是先將房屋元件依已知的、內外方位投影至航照像片,以消除模型邊線投影與房屋影像邊緣線像元之間的不符值為目標函式,採用最小二乘法逐步疊代求出最佳套合時的模型參數。為探討套合過程中各項因素對成果之影響,本文首先針對環域寬度、像片多寡及模型參數的收斂範團(pull-in-range)進行實驗分析。接著在航照像片上選取十棟成功大學校區周圍的各式建物,以人機互動方式逐一以矩形和屋脊形元件進行近似套合,再由電腦以最小二乘模型-影像套合法自動計算最佳套合時之模型參數,最後換算出屋頂角點之物空間座標與傳統航測立體製圖成果進行比較,以說明最小二乘 CSG 模型-影像最佳套合法之實驗精度及其可行性。

Abstract

Semi-automatic model-based building extraction is the major research topic of digital photogrammetry. The affectiveness of model-image fitting algorithm is the key of semi-automatic model-based building extraction. In this paper a building is modeled by some combinative primitives, and model-image fitting is proceeded primitive by primitive. After fitting, complex buildings can be modeled by combining simple primitives defined by the theory of Constructive Solid Geometry (CSG). A model primitive can be trans­formed into the object coordinate system to form its size and position with the shape and pose parameters. With the known photo exterior and interior orientation parameters the primitive model and image features can be transformed into the photo coordinate system. The fitting is evaluated based on the correspondence between the projected model wire frame and the edge pixels. The least-squares fitting algorithm is applied to solve the optimal fitting and estimate the final model parameters. Ten houses composed of box and gable­roof primitives are tested for demonstration. The experimental results are compared with the data of manual measurements.

關鍵字

建物萃取、模型與影像套合、最小二乘、建構實體幾何、建物重建

Keywords

Building Extraction, Model-image Fitting, Least-squares Fitting, Constructive Solid Geometry, Building reconstruction

附件檔名

華芸線上圖書館

N / A

備註說明

200109-6-3-57-73

Pages:

75-84

論文名稱

「技術短文」以蘭氏面假設下大氣改正模式遙測耕土壤反射率之誤差估算

Title

The Estimation of Error of Retrieved Plowed Field Reflectance by Atmospheric Correction Model based on Lambertian Surface Assumption

作者

劉建慧

Author

c. H. Liu

中文摘要

由於自然界地表物均為非蘭氏面,因此以蘭氏面為假設之大氣改正模式所反演之地表反射率,必定會產生誤差。本文使用6S模式估計此誤差。地表物選定為耕土壤,其 BRDF 使用 Roujean 模式。波長選定為0.63μm。在此考慮因太陽天頂角及氣膠光厚度之變化。研究結果顯示,在一般情形下,此誤差在背向散射區較前向散射區大。即使是乾淨天氣,背向散射觀測處所造成誤差不可忽略。在太陽天頂角60°,天氣為混濁情形下,觀測天頂角-60°處之反射率誤差可高達0.13 。當太陽天頂角增加及/ 或天氣由乾淨至混濁時,此誤差也增加。

Abstract

There exist some errors of the retrieved surface reflectance by using an atmospheric correction model based on Lambertian surface assumption, since the natural targets are not Lambertian. In this study, 6S is used to estimate the errors. Plowed field is select and a linear BRDF model is used. Wavelength at 0.63ìm is considered. Errors varied with solar zenith angle and aerosol optical depth are studied. The results show that the errors are larger at back-scattering region than fore-scattering region. These errors cannot be neglected, even in clear sky. The error can be up to 0.13 at view angle -60°, when solar zenith angle is 60° and the sky is hazy. When the solar zenith angle and/or sky changes from clear to hazy, the errors generally increase.

關鍵字

蘭氏面、雙向反射分布函數、反射率

Keywords

Lambertain, BRDF, reflectance

附件檔名

華芸線上圖書館

N / A

備註說明

200109-6-3-75-84

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