Character Extraction of Vehicle Plate Directly from Compressed Video Stream

Character extraction of vehicle plate is conducted directly in MPEG compressed domain. Firstly, vehicle plate region is detected by thresholding the weighted horizontal texture energy, in which adaptive threshold is used, followed by a series of post processing, e. g. morphological operations, connected component analysis, filtering with aspect ratio constrains. Secondly, block’s DC+2AC texture intensity projection profile is used to implement the character of vehicle plate localization accurately. Then after minimal decompression processing and contrast adjustment on the located region, OTSU thresholding technique is used for character extraction. Experiment results show the effectiveness of the proposed algorithm.