Fast downward-looking target matching technology on missilein large field of view

Downward-looking target matching on missile is a prerequisite for hitting effect evaluation. A stable SIFT algorithm is proposed to implement fast downward-looking target matching in large field of view. The method initially identifis positions and scales of key points by calculating local maxima in scale space and eliminates the response points on the unstable edge of low-contrast key points. Then seed points and their eigenvectors are sketched based on the gradient direction histogram of key points neighboring pixels, further eigenvectors of key points are obtained. Finally, distance functions are used as similarity measure for image matching. Compared with several traditional methods, the proposed algorithm has higher real-time capability in experimental results. Furthermore, the improved algorithm has better robustness due to increasing of eigenvector dimensions on the basis of original one.