Improved vehicle plate location method based on block segmentation

An improved location algorithm of the vehicle plate is proposed in the paper. Firstly, the plate image is segmented into many blocks. Then the horizontal density of character edge in each block is used to obtain the candidate plate region. Since the characters in plate are uniformly distributed basically, the proportion of the area being occupied by character edge to the whole plate will be in some range. Likewise, there is the same proportional relation for every sub-region in the whole plate region. When the change of the image catching distance brings on the change of plate size, the ratio is still in the above range, and is suited to the plate of the different size. Meanwhile, because the plate position is located by the block searching, the location speed increases evidently. The experimental results show that the proposed algorithm has high accuracy and robustness.