應用方向約制Hough轉換法於空照影像建物圖徵抽取

On the Building Feature Extraction from Aerial Image with Orientation Constrained Hough Transformation

張崑宗(Kuen-Tzung Chang) ； 何維信(Wei-Hsin Ho) ； 史天元(Tian-Yuan Shih)

《航測及遙測學刊》 2卷2期 (1997/06) Pp. 15-35

https://doi.org/10.6574/JPRS.1997.2(2).2

摘要

Hough轉換是一種常用於萃取影像中幾何要件的方法。標準Hough轉換雖可以偵測簡單線形，但由於轉換後位置偏移所造成之關連性誤差，使得應用於結構較複雜之幾何形狀萃取時，效果未盡理想。本文提出方向約制Hough轉換法，萃取數化航照中建物邊緣線之直線。本方法使用鏈結碼之概念，以十二種圖型進行方向分析，除了可以減少轉換點數、增加萃取效率以外，尚可提供線形物法角之預估值，以設定轉換區段，減低關連性誤差之影響。本研究利用實例，分析參數之影響；並以SNR指標、容錯指標、執行所需時間，評估方向約制轉換與標準Hough轉換之間差異與效率。以此方法萃取航測影像中地物特徵主要邊緣線之主要目的，在協助後續辨識、認知工作之進行。

關鍵字

幾何判識要件 ； 方向約制Hough轉換 ； 地物特徵

並列摘要

Hough Transform is an effective method for extracting geometric primitives form image. However, the standard scheme suffers from the correlated error when the image content is complex. In this study, the orientation constrained Hough transform is proposed for the extraction of building edges from the scanned aerial photo. Based on the chain code concept, twelve templates are defined for the screening of line components to reduce the range of the parameter space. This procedure reduces the number of transformations required, and also limits the influence of the correlated error. Numerical experiments are performed with both the standard Hough transform and the proposed scheme. Three robustness indices, SNR, and the execution time are computed for evaluation.

並列關鍵字

Geometric Primitives ； Orientation Constrained Hough Transform ； Man-made Features