Research on Straight-Line Extraction for Aerial Images

Line and plane feature can provide more information than point feature, thus 3D reconstruction based on high-level features, such as line and plane, is an important development trend in Digital Photogrammetry and Computer Vision. Several methods for extracting straight line are researched, and the main procedures can be introduced as follows. Firstly, image is preprocessed by Wallis filtering that is used to enhance the image contrast and reduce the noise, so it is easy to extract more lines. Secondly, Laplacian of Gaussian operator (LoG) and Canny operator algorithms are compared to locate the edge by detecting discontinuity variation in image. Thirdly, Hough transform or perceptual organization based on hypothesis testing are compared and tested for combining and fitting fractured short line segments into a whole line. Lastly, the least square template matching algorithm (LSTM) is done to get higher precise (sub-pixel) located lines. In the experiment, different algorithms for straight line extraction of aerial images are realized and compared, in order to faster achieve richer and higher accurate straight line information, which can pave the way of image understanding and image matching.