台灣位處於亞熱帶地區，是個海島型的國家，境內有很多超過一千公尺以上的高山，加上夏天對流旺盛以及颱風的影響，所以在台灣地區天空中常常會有雲霧的生成。因此對於光學衛星拍攝地表的影像會產生很大的影響。因為光學衛星的光波長無法穿透雲霧，導致地表資訊被雲霧所遮蔽，因此目的要將光學衛星影像上的雲霧濾除，以產生一張乾淨無雲的影像。本研究選取福爾摩沙二號的衛星影像作為研究影像，選取位於台灣東北角的地區包含雲的影像。首先先利用色彩轉換將紅、綠、藍色彩空間轉換成色調、飽和及亮度的色彩空間，用將雲在影像中加以凸顯。接著在影像中選取訓練樣本，利用監督式分類法來分類雲及陰影，在此運用最小歐基里德及城市區塊距離來做分類，分類完成後再利用型態學的方法來修復分類結果的破損部分，以及濾除雜訊。最後用分類結果來計算雲與陰影的相關係數，來找對應雲的陰影所在，並根據影像拍攝時的太陽仰角及方位角，還有兩者相對位置，估算雲的高度。此外，我們也運用白化-反白化矩陣去校正兩張不同時期的衛星影像，在雲以及陰影濾除後做影像鑲嵌，產生一張無雲及陰影的乾淨影像。

Taiwan is an island located at monsoon climate section in the Pacific Ocean. There are often clouds in the sky which poses restrictions for the development of optical remote sensing. Cloudless images over the island will take months to retrieve. For the sensors of visible and infrared light on earth resource satellites, the interference of cloud becomes a serious issue to deal with. In this case, we have to locate the cloud from the satellite image. We transfer image from (Red, Green, Blue) RGB system to the (Hue, Saturate, Intensity) HSI system to locate clouds. Then the clouds and shadow can be classified on the satellite image by supervised pure-pixel classification. We choose the city block, and Euclidean distance. We apply to classify the clouds and shadow. After this, the morphology to renovate the classify result and reduce noise. Finally we apply Image Color Correction for images collected of different dates and replace the cloud with mosaic process, and produce the cloudless images in an automatic sense. We can also calculate the correlation between cloud and its shadow to estimate the cloud height

[1] 蔡博閎, 衛星影像雲層遮蔽區域之移除與填補演算法, 國立成功大學碩士論文, 2010.
[2] Nguyen, T. H, Ryutaro, T., Cloud Removal of Optical Image Using SAR Data for ALOS Application. Experimenting on Simulated ALOS Data, The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences Beijing 2008. Vol. 37, pp. 379–384.
[3] International Satellite Cloud Climatology Project, http://isccp.giss.nasa.gov/index.html
[4] 中央氣象局, http://www.cwb.gov.tw/V7/index_home.htm
[5] Mayer, R., Bucholtz, F.,and Scribner, D., Object Detection by Using “Whitening/Dewhitening” to Transform Target Signatures in Multitemporal Hyperspectral and Multispectral Imagery, IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING, Vol. 41, No. 5, May 2003.
[6] Haydn, R., Dalke, G.W., and Henkel, J., 1982. Application of the IHS color transform to the processing of multisensor data and image enhancement. in Proc. Int. Symp. Remote Sens. Arid and Semi-Arid Lands, Cairo, Egypt, pp. 599–616.
[7] Tsai, J. D., Comparative Study on Shadow Compensation of Color Aerial Images in Invariant Color Models, IEEE Translations on Geoscience and Remote Sensing 2006, vol. 44, NO. 6. pp.1261-1271.
[8] 陳秉斌, 以色彩名稱為基礎之影像內容檢索系統, 南台科技大學碩士論文, 2007.
[9] 徐逸祥, 遙測影像中雲霧的偵測及雲霧干擾之去除, 國立台灣大學碩士論文, 2006.
[10] 張維恕, 劉正千,高植被低裸岩區域之高光譜遙測影像混合像元分離技術探討,中國地質學會九十四年年會暨學術研討會, NCU,2005,(NSC93-2625-Z-006-011).
[11] Richards, J.A, Jia, X.P, Remote Sensing Digital Image Analysis, Fourth Edition, ISBN-13 978-3-540-25128-6., 2006.
[12] Lillesand, T.M., Kiefer, R.W., Remote Sensing and Image Interpretation, Fourth Edition, John Wiley and Sons, ISBN 9971-51-427-3, 2002.
[13] Gonzalez, R.C., Woods, R.E., and Eddins, S.L., Digital Image Processing Using MATLAB, Pearson Education India, 2002.
[14] 曹伶伶,利用多光譜影像的光譜與空間資訊結合數學型態學進行海洋油汙偵測, 國立中央大學碩士論文, 2009.
[15] Simpson, J. J, Jin, Z., and Stitt, J. R., Member, IEEE, Cloud Shadow Detection Under Arbitrary Viewing and Illumination Conditions, IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING, VOL. 38, NO. 2, pp. 972-976, Mar, 2000.
[16] 國家太空中心, http://www.nspo.org.tw/tw/
[17] 林文偉,類神經網路在MODIS 衛星影像雲分類之應用,國立中央大學碩士論文,2005.
[18] World Meteorological Organization, http://www.wmo.int/pages/index_en.html
[19] Wlsh, T., Ashikhmin, M., and Mueller, K., Transferring color to greyscale images. ACM Transactions on Graphics, 3 (7), pp.277-280, 2002.
[20] Tseng, D. C., Tseng H. T., Chien C. L., Automatic cloud removal from multi-temporal SPOT images, Applied Mathematics and Computation 205, pp. 584–600, 2008.
[21] Meng, Q., Borders, B. E, Cieszewski, C. J, and Madden, M., Closest Spectral Fit for Removing Clouds and Cloud Shadows, Photogrammetric Engineering & Remote Sensing, Vol. 75, No. 5, pp. 569–576, 2009.
[22] Chen, F., Zhao, Z., Peng, L., Yan, D., Clouds and Cloud Shadows Removal from Highresolution Remote Sensing Images, pp. 4256–4259, 2005.
[23] Cihlar, J., IEEE Associate Fellow, and Howarth, J., Detection and Removal of Cloud Contamination from AVHRR Images, IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING, VOL. 32, NO. 3, pp. 583-589, 1994.
[24] Dare, P. M, Shadow Analysis in High-Resolution Satellite Imagery of Urban Areas, Photogrammetric Engineering & Remote Sensing, Vol. 71, No. 2, pp. 169–177, 2005.
[25] Wang, B., Ono, A., Muramatsu, Kanako., Automated Detection and Removal of Clouds and Their Shadows from Landsat TM Images, IEICE TRANS. INF. & SYST., Vol.E82–D, No.2, pp. 453-460, 1999.
[26] Sylvie Le, H. M, André, C., Use of Markov Random Fields for automatic cloud/shadow detection on high resolution optical images, Vol. 1. ISPRS Journal of Photogrammetry and Remote Sensing 64, pp. 351-366, 2009.
[27] Prati, A., Miki''c, I., Grana, C. and Trivedi, M. M, Shadow Detection Algorithms for Traffic Flow Analysis: a Comparative Study, IEEE Intelligent Transportation Systems Conference Procedings, Oakland, USA, pp. 340-345, 2001.
[28] 曾筱婷, 以多時段的SPOT衛星影像做雲層自動去除, 國立中央大學碩士論文, 2005.
[29] 王宗銘, 具可逆能力的色彩轉換演算法, NCS全國計算機會議, 2005.
[30] 陳獻廷, 利用高光譜影像作異常物偵測, 國立中央大學碩士論文, 2006.
[31] 李存軍, 王人潮, 基於Landsat影像自身特徵的薄雲自動探測與去除, 浙江大學學報, Vol. 40, No. 1, 2006.
[32] 葉精國, 自動化衛星影像雲及雲陰影遮蔽區偵測及復原之研究,國立中興大學碩士論文, 2006.
[33] 紀萬偉, 無參數加權特徵萃取隊遙測及醫學影像目標偵測的應用, 國立中央大學碩士論文, 2007.
[34] 張正忠, 影像與視訊色彩轉換之研究, 亞洲大學碩士論文, 2009.