ENGLISH

17卷/4期

17卷/4期

華藝線上圖書館

Pages:

237-250

論文名稱

ADS-40 數值航照影像中雲蔽區多重階層式資訊還原模式之研究-以濁水溪農業區為例

Title

Evolving a cloud removal model for multi-spectral aerial photos of ADS-40 images - Case study in agricultural areas of Choshui River Basin

作者

雷祖強, 李哲源

Author

Tsu Chiang Lei,Che-Yuan Li

中文摘要

遙感探測影像主要透過飛行載具於地表高空進行拍攝,因此拍攝時易受大氣影響,例如雲(Cloud)或霧(Haze)。本研究以2 期ADS-40 數值航空攝影影像為研究材料,以彰化縣濁水溪農田區為測試範圍,將影像受雲霧遮蔽區域(以下簡稱雲蔽區)分成「厚雲區」(Thick cloud zone)、「薄雲區」(Haze zone)、「陰影區」(Shadow zone)及不受雲蔽影響的「無雲區」等四大區域,針對不同雲蔽區進行1. 不同時期影像之厚雲資訊補遺。2.暗原色先驗演算法(Dark Channel Prior Algorithm)之薄雲區資訊反演。3.Retinex 演算法進行陰影區資訊增揚運算,本研究評估方法則以影像分析常用的均方根誤差(Root Mean Square Error, RMSE)、峰值訊噪比(Peak Signal to Noise Ratio, PSNR)及結構相似性品質指標(Structure Similarity Image Measurement, SSIM)進行雲蔽區影像處理前、後之影像品質評估比較。根據評估結果顯示,雲蔽影像經過本研究模式運算後,RMSE 從88.02 降至17.63,PSNR 從9.24 提升至23.20,而SSIM 也從0.74 提升至0.97。整體而言,本研究所提出之雲蔽區多重階層式資訊還原模式確實能e夠降低雲蔽效應,提升影像品質與可視度。

Abstract

Generally, atmospheric haze has important ramifications in remote sensing data. In this work,the theaerial photographs of ADS-40 image at Choshui River agricultural areas are divided into 4 regions which are thick clouds region, haze region, shadow region and normal region through a hybrid region detect model of ATSA (Automated Threshold Selection Algorithm) and MLC (Maximum Likelihood Classification) methods, respectively. In addition, for the different regions of atmospheric haze effects, this work will also develop an efficient hierarchical algorithm for mixed modes which are correct and verifies the image properly. These modes are as below: 1. Mosaic thick cloud region: prophase images provides new information for thick cloud region; 2. Restore haze region: spectral information was invested by DCPA (Dark Channel Prior Algorithm) method, and 3. Enhance shadow region: the Retinex algorithms were applied to enhance these shadow regions. After that, this work check the original and processed image quality assessments of this research processing with RMSE (Root Mean Square Error), PSNR (Peak Signal to Noise Ratio) and SSIM (Structure Similarity Image Measurement) indicators, respectively. It shows that the processed image with this hierarchical mixed mode of this study is better than those of the original image of ADS-40 aerial photographs. The index of RMSE reduced from 88.02 (original image) to 17.63 (processed image), PSNR index value improved from 9.24 (original image) to 23.20 (processed image) and SSIM value upgraded from 0.74 (original image) to 0.97 (processed image), respectively. Finally, in this study, the outcomes showed that the hierarchical mixed mode for image processing procedure exceeds that of the original image of agricultural areas evaluation from ADS-40 image.

關鍵字

大氣灰霾、雲蔽效應去除、影像還原、影像品質評估指標

Keywords

Atmospheric Haze, Remove Could Effect, Image Restoration, Image Quality Assessment Index

附件檔名

華芸線上圖書館

N / A

備註說明

N / A

Pages:

251-266

論文名稱

以特徵點為基礎的航測影像浮水印

Title

Keypoint-Based Digital Watermarking For Photogrammetric Images

作者

徐百輝, 陳志丞

Author

Pai-Hui Hsu,Chih-Cheng Cheng

中文摘要

隨著個人電腦與高速網路的日漸普及,人們可以快速且輕易地搜尋並取得各式各樣的數位資料,如何應用訊號處理技術進行數位資料的版權維護及管理也成為一個熱門的研究議題。目前有關於一般數位多媒體資料的數位浮水印研究已有相當成熟的技術與豐碩的成果,惟對於需高額經費產製、重要性甚高、應用性甚廣之空間資料,其相關的浮水印研究卻相當少見。本研究針對網格式空間資料進行數位浮水印分析及探討,以航空攝影取得之數位影像為例,進行數位浮水印的測試及影響分析,並針對航空影像的主要應用,提出一個以點特徵為基礎的浮水印演算法,進行浮水印的強韌性測試及分析,以因應不同使用者後續處理影像資料後仍能達成版權保護的目的。經實驗證明,本研究所提浮水印方法確實具一定的強韌性,可以抵抗大部分的影像攻擊,同時亦可以保有航測影像資料的品質,嵌入本研究所提方法之浮水印後,影像匹配成功率至少較一般浮水印演算法提高了百分之三。

Abstract

With the rapid development of information technology (IT) and communication technology (CT),people can obtain every kind of digital data more convenient than before. The consequence is that the “copyright protection” which prevents digital data from been duplicated illegally should be paid much more attention. In the past, digital watermarking technology has been successfully applied to the “copyright protection” of various kinds of digital multimedia data, however the researches and  applications of applying digital watermarking to geo-information data are still very inadequate. In this study, the influence of the digital watermarking on the photogrammetric images is firstly analyzed. A novel digital watermarking algorithm based on the keypoints is proposed especially for photogrammetric images. The robustness of the embedded digital watermark and the impact on photogrammetric images are finally evaluated and analyzed. The experiments show that the proposed algorithm has high robustness on watermarking and little influence on the quality of the photogrammetric images. The success rate of image matching has been improved by 3% using the proposed watermarking algorithm.

關鍵字

數位浮水印、強韌性、幾何轉換

Keywords

Digital Watermarking, Robustness, Geometric Transformation, Deformation

附件檔名

華芸線上圖書館

N / A

備註說明

N / A

Pages:

267-285

論文名稱

多尺度三維數位房屋模型建置

Title

Three Dimensional Digital Building Modeling for Multiple Level of Detail

作者

蔡富安,張智安, 張桓, 陳良健,陳杰宗

Author

Fuan Tsai 1,Tee-Ann Teo,Huan Chang, Liang-Chien Chen,Chieh-Tsung Chen

中文摘要

三維數位城市為現今空間資訊領域發展之重要議題,其中人造建築之三維房屋模型乃是最為重要之基礎物件之一。本研究結合航遙測科技、數位攝影測量、電腦圖學等領域之技術,針對臺灣地區房屋的特性,研發出符合OGC CityGML 所定義的LOD1、LOD2 及LOD3 之房屋模型建置方法,並評估所建置三維模型的品質。研究中使用的資x料包括:大比例尺數值地形圖、空載及近景數位影像、空載及地面光達點雲、數值地形模型、高解析衛星影像等。本研究另將現今多數三維展示系統主要使用的LOD1 及LOD2等級之房屋模型,記錄與分析個別資料成本及建置成本。此研究之成果可作為未來進行大規模三維房屋模型建置以及相關應用重要的參考依據。

Abstract

Three-dimensional (3D) digital city is an emerging topic in the development and application of Geo-information. Building model is one of the most important components in a 3D digital city system. This paper presents viable strategies for generating 3D building models of different levels of details from assorted sources of spatial data, including large-scale topographic maps, aerial photographs, satellite images, close-range images and range data acquired with terrestrial laser scanners. Different approaches integrating photogrammetry, remote sensing and computer vision technologies are proposed according to different data and model requirements. The developed algorithms are designed for 3D modeling of complicated building pattens in the cities of Taiwan. The results demonstrated in this paper indicate that the proposed strategies and methods can generate 3D building models of different levels of details from different sources effectively. In addition, accuracy and cost analyses were also performed in order to provide more comprehensive references for future digital city implementations and related applications.

關鍵字

數位城市、房屋模型、細緻度等級、成本分析

Keywords

Digital city, Building modeling, Level of Detail (LOD), 3D reconstruction, Cost and effectiveness analysis

附件檔名

華芸線上圖書館

N / A

備註說明

N / A

Pages:

287-293

論文名稱

應用衛星測高偵測臺灣西南海域渦漩

Title

Oceanic Eddy Detection in the Sea off Southwestern Taiwan Using Satellite Remote Sensing Data

作者

鄭宇昕,何宗儒

Author

Yu-Hsin Cheng,Chung-Ru Ho

中文摘要

本研究使用1992 年至2011 年的衛星海面測高資料,探討臺灣西南海域渦漩在海洋表面的分布與移動。為了能夠客觀且自動化的從大量衛星測高資料中追蹤海洋渦漩,本研究根據Okubo-Weiss 參數與相連元件標記演算法(connected component labeling)為基礎,發展了一個渦漩自動偵測與追蹤演算法,並對偵測出的渦漩面積大小、相對渦度、非線性程度、中心移動速度、生命週期、移動路徑與動能變化等性質,進行時間與空間上變化的研究。結果顯示絕大部分的渦漩都在北緯21.5 度、東經120 度為中心的100平方公里內生成,其中又以暖渦居多。生成之後大部分的暖渦會沿著約500 公尺的等深線往西南方傳遞,而冷渦則是在東經118 度與121 度之間徘徊。在物理性質方面,不論面積、振幅、生命長度或是渦漩動能,在此海域生成的暖渦都會比冷渦來的強,且此海域生成的渦漩都具有極高的非線性特性。

Abstract

Absolute dynamical topography data derived from multi-satellite altimetry were used to analyze the formation and the transformation of oceanic eddies in the sea off southwestern Taiwan from 1992 to 2011. To track and detect eddies, we developed an integration filtering algorithm based on connected component labeling and the Okubo-Weiss parameter. Area, relative vorticity, nonlinearity parameter, amplitude, central velocity, lifetime, propagation pathway and kinetic energy of eddies are determined by the algorithm. The results indicate that eddies are almost generated around 100 km within the center of 21.5ºN and 120ºE. The number of warm eddy is more than that of cold eddy. Most warm eddies propagate to southwest along about 500 meter isobaths but cold eddies linger between 118oE and 121oE. The area, amplitude, lifespan, and eddy kinetic energy of warm eddies are greater than those of cold eddies. Eddies in the sea off southwestern Taiwan possess very high nonlinear property.

關鍵字

衛星測高、海洋渦漩、臺灣西南海域

Keywords

satellite altimetry, oceanic eddy, southwestern Taiwan

附件檔名

華芸線上圖書館

N / A

備註說明

N / A

Pages:

295-308

論文名稱

「技術短文」結合監督模式與共克利金法估算河川污染指標面化圖

Title

Study of river pollution index (RPI) by using different SPOT image corrections and estimation procedures

作者

施明倫,洪志豪,林珈禎

Author

Min-Luen Shih,Chih-Hao Hung,Jia-Jhen Lin

中文摘要

本研究擬結合大範圍但精確性低的SPOT 衛星遙測影像(Remote sensing, RS)與小範圍但精確性高的現場水質採樣分析資料,以監督學習模式及空間統計分析方法面化建立台灣河川流域水質污染指標分布圖(River pollution index map, RPIM)。監督學習模式採用支撐向量機迴歸模式 (Support vector regression,SVR),而空間統計方法則採用地理資訊系統 (Geographic Information System, GIS)常用之共克利金內插方法(Co-kriging , CK)。利用前期歷史資料的學習建模,藉以概略推估當日衛星影像的估算值,再加入當日少數定點水質採樣資料作空間內插,兼顧兩種方法的優點建立遙測河川水質污染面化圖,最後再與單獨個別方法的估算結果作比較。

Abstract

This study concentrated on satellite image’ correction processes and its application on water pollution estimation. In addition to the existing established Geometric Correction, the image correction was evaluated by combining radiation with atmospheric corrections. In SVR model’s input variables, we optimized from not only the original four bands in SPOT 4 and 5, but also the derived bands refer to different author' recommendations, Additionally, the Digital Elevation Model (DEM) was also used as one of the input variables. Therefore, two different model estimation procedures were evaluated: average river pollution index from simulated single river pollutant's score (RPI-Si) and average river pollution index from simulated single river pollutant's concentration (RPI-C). Finally, average river pollution index which predicted from the above compared best method was Co-Kriging (CK) with calculated RPI from few measured water quality sampling stations was also evaluated. The results showed that the short wave infrared band of SPOT image also has the positive contribution on the prediction results of river pollution index. Among different river pollution index estimation procedures, RPI_Si is the best way to estimate the final average water quality index. Furthermore, if we can interpolate the data of monitoring stations with the data predicted from SVR model for the display of river pollution index maps, the results indicated more improvement than that of only using SVR model. Conclusionally, when we combine the precised traditional river water quality monitoring data with the roughly advanced image predicted data from SVR model will be the feasible way as so far in order to establish a sketch map of surface river pollution index.

關鍵字

遙測(RS)、支撐向量機(SVR)、共克利金(CK)、河川水質污染指標面化圖(RPIM)、 數值高程(DEM)

Keywords

Remote sensing, Support vector regression, Co-kriging, River pollution index, Atmospheric corrections.

附件檔名

華芸線上圖書館

N / A

備註說明

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