Vector map is a kind of computer graphics formed by matrix of vectors. These vectors are results of cross-correlation of two related particle images.This technique is called PIV(particle image velocimetry). A new algorithm for extraction of car license plate is introduced, which is called VMLA(vector map location algorithm). The idea of VMLA is inspired by the method to get the cross-correlation vector map of PIV. It based on thefact that the two edges of strokes of license plate characters and numbers cause a special local structural pattern in the cross-correlation vector map. Using this idea, the correct position of a plate could be extracted from vector maps of license plate images with complicated backgrounds. VMLA is adaptive to various license plate sizes and it also runs in real-time. Testing results on 540 license plate images show that the method is valid and efficient.
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