Abstract:
To solve the problem in feature extraction of side scan sonar images that the line feature extracted by Hough transform is not satisfactory due to the deficiency of the basic space conversion method, a better space conversion method is proposed. This method needs to establish two image edge mask matrices — one for maintaining the original shape to find the straight line features, and the other for reducing the corresponding edge points according to the edge point transformation. This method can ensure that the feature points belonging to the straight line participate in the formation of linear features. However, the linear features detected in the line segment detection(LSD) algorithm will be broken due to intersection, hence a method of fitting the broken line features is designed, in which the straight line features being determined as ‘broken’ are simulated via angle and position so as to deal with the trouble of having too short or too much straight lines due to the fracture of the linear features, and then the appropriate straight line features are selected according to the length threshold. The linear feature extraction of side scan sonar images verifies that the improved Hough transform can extract the line features better, and the optimized LSD algorithm can reduce the influence of line feature fracture. For the sonar image to be processed, the number of point feature extraction is large, which can not reflect the characteristics of the image content well; and the improved line feature can extract the outline of the im-age content, and the information is rich, which better expresses the content of the image. It is provide reference for relevant line feature extraction research.