為有效了解地表資訊，可視研究目的而利用各種遙測方法獲取地面影像，但不論目前常用之飛機、或是以衛星為載具之空中攝影測量等相關研究，在影像獲取方面，常面臨成本費用、機動性、比例尺需求、後續影像處理等問題。因此，本研究選定一小流域面積之河川作為實驗區，並設計以氣球為載具之數值航空攝影方式，裝載CCD攝影機以及數位攝影機，透過CCD攝影機，即時無線傳輸地面影像至監視螢幕，調整氣球至預定之位置後，遙控啟動數位攝影機之快門裝置。 　　研究設計之攝影方式曾實際應用於偵測河道之變遷，由成果影像中檢核點之精度結果，以及套疊正射糾正並鑲嵌後之河道影像與地形圖之成果，證明氣球載具之數值航空攝影方式，確能有效應用於大比例尺製圖之研究。 / Using a flexible and efficient way to obtain aerial images has been the primary purpose of this study. The balloon platform was used to take aerial images. A video camera and a digital camera were fixed together in a durable plastic box, and hung on the balloon. The video camera was used to monitor the ground view, and its image could be telemetered remotely and displayed on a LCD monitor arranged on the ground. Once monitoring the area of interest shown on the LCD, the shutter button of the digital camera was then pushed remotely and the interested image was taken. 　　The resultant images were ortho-rectified for analysis and comparison. The accuracy of aerial images was examined by check points. The results showed that the images achieved sub-pixel accuracy and were well-matched with the 1/1000 digital topographic maps. This expressed that it was really a useful and efficient method of taking large-scale images for a small research area. 　　At last, post-classification comparison method was introduced to detect change of the ortho-rectified images which were taken in three different periods. The classification maps and the from-to change class information clearly indicated the change of river way among various periods.

本研究以不同時期之航遙測影像偵測宜蘭海岸濱線變遷，影像來源包含1947年之舊航照影像、1971年的美國Corona衛星影像、1985年的像片基本圖、2003年的SPOT-5衛星影像及2009年以Z/I DMC(Digital Mapping Camera)航空數位相機所拍攝之高解像力航照影像。 由於影像獲取的時間與感測器皆有所差異，故本研究透過不同的方式處理資料，將影像地理對位，並利用地理資訊系統(Geographic Information Systems, GIS)軟體數化濱線及沙灘(丘)，且以套疊分析觀察不同時期濱線與沙灘變遷之情形，最後收集宜蘭地區的自然或人文資料如潮汐、降雨量與輸沙量等，分析宜蘭海岸變遷的原因。而在濱線萃取方面，由於以人工數化方式太耗時間與人力，故嘗試以半自動化方式如影像分類或影像分割萃取濱線，並與人工數化結果比較。研究結果顯示，利用多時期之遙測影像，並結合GIS之空間分析功能，確可有效掌握濱線與沙灘(丘)的歷史變化概況。 / This study used multi-temporal remote sensing images to detect shoreline changes along the Yilan coast. Various types of remote sensing images were used in this study, including old aerial images taken in 1947, Corona satellite images acquired in 1971, photo base map produced in 1985, SPOT-5 satellite images obtained in 2003, and high-resolution aerial images taken in 2009 by using Z/I DMC (Digital Mapping Camera). Because these images were taken in different time using different sensors, different procedures were applied to process the data and georeference the images to a common coordinate system. GIS (Geographic information Systems) software was used to digitize shoreline and the beach area, and overlay analysis was applied to find the shoreline changes in different time periods. Then various ancillary data such as tides, precipitation, and sediment load was collected to analyze the causes of coastal changes in Yilan. For shoreline extraction, manual digitization required a lot of time and manpower. Therefore, semi-automatic method such as image classification and image segmentation was applied to extract shoreline. The results show that, by using multi-temporal remote sensing images and spatial analysis functionalities of GIS, the historical changes of shoreline and beach area can be detected effectively.