多重影像中線型特徵物與物空間直線進行匹配之研究

在以航空影像進行自動化建物模型的重建時，常以搜尋建物邊緣線為出發。但在多張影像中進行這個工作時，由於一般低階灰值邊緣線的萃取及鏈結只顧及了影像中的灰值變化以及像空間內簡單二維幾何特徵，並不容易辨識出所搜尋到的邊緣線是否共軛。再加上影像中雜訊、陰影、遮蔽、弱反差或是建物本身紋理繁複的影響，以致於一開始所萃取的邊緣線常是破碎、不連續，而且還含有許多非建物邊緣線。由於萃取時並未考慮建物邊緣在物空間中三維知識，以致於所得到的邊緣線大部分與實際物空間邊緣線並不一致。本研究乃以物空間的觀點找出建物邊緣線在物空間和影像空間中具有的關係，以一個適當的函數模式，來把多張影像中萃取出的邊緣線在物空間中匹配成直線。並藉由實驗找出正確匹配時，此模式應具有的統計特性，建立適當的統計檢定方法，供自動判斷匹配是否成功的依據。

關鍵字

建物重建；建物邊緣線；多張影像；邊緣線匹配；物空間匹配

並列摘要

Building reconstruction from aerial images begins often with the search of building edges. But searching of conjugate building edges in multiple images is not an easy task. Since low-level edge extraction in image space can only take consideration of gray-level changes and make very simple linking of edge pixels based on very simple criteria like direction of gradient, gray value consistency along edges, etc., thus no information from object space is considered in that stage, a large percentage of the extracted gray-level edges are not building edges at all. More over, due to noises, shadows, occlusions, weak contrast or even due to complexity of building surface texture itself, most of the extracted building edges are not even complete. They are broken and shown only as piecewise line segments. Since gray-level edges are projected images of true edges in object space, the search for conjugate building edges in multiple images should be more successful if information from object space could be taken into consideration. It is thus the aim of this article to describe how simple object space knowledge of straight edges could help the search for conjugate line segments in multiple images. Functional model for matching of the image space line segments onto object space straight lines are derived and statistical testing procedures for testing the correctness of the matching are developed.

並列關鍵字

building reconstruction ； building edges ； multiple images ； edge matching ； object space matching

國際替代計量

多重影像中線型特徵物與物空間直線進行匹配之研究

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