- 期刊
高解析力衛星影像控制點之自動化萃取
Automated Extraction of Control Points for High Spatial Resolution Satellite Images
摘要
進行衛星影像的幾何校正通常需控制點，常用的控制點選取方式是以人為的方法比對影像與地圖，將影像中的明顯特徵物選取出來，然後在地圖上找到對應點的座標當成控制點。高解析力衛星影像，如一公尺解析力的IKONOS全色態影像，具明顯的影像特徵相當多，因此極具控制點選取自動化的潛力。本文主要目的是研究高解析力衛星影像控制點自動化選取的方法，控制點以道路交口之影像特徵為研究目標。研究方法以數位影像處理為基礎，其步驟可分為二大部分，第一部份為道路萃取，第二部分則為道路交點搜尋。測試結果顯示本研究方法可有效地自動選取控制點，達到衛星影像控制點自動化萃取之實用性。
並列摘要
As IKONOS satellite with 1-m resolution has been lunched in 1999, mapping using space-borne images will be a hot issue in computer vision area and photogrammetry. It is obvious that one of the great challenges to process the high spatial resolution satellite images will be the geometric correction practice. Conventionally, the positioning of the image control points is manually performed by a labor-intensive and time-consuming procedure. Furthermore, due to the abundant image contents, high spatial resolution satellite image would have plenty of the qualified control points. As a result, the manual identification and positioning of control points will become even more inefficient and unbearable. Therefore, the main objective of this study proposes to develop an automated image processing technique to extract the control points for the high spatial resolution satellite images. Among numerous spatial features, this study considers even widespread road intersection the main target to perform the control point extraction. The proposed method consists of two parts. The first part is ”road extraction” consisting of four steps image-processing algorithm and the second part is ”road intersection searching” consisting of two steps image-processing algorithm. A series of high spatial resolution satellite images are used to test the proposed method. The results shows that the oposed image processing approach has the potential to automatically position the control points in the high spatial resolution satellite image.