Video Speed Measurement Based on Boundary Location of License Plate Characters

Aiming at the problem that video speed measurement has a large error under bayonet socket environment, a method to improve the velocity precision is proposed. The second character of license plate as a feature of vehicle positioning block is used, wavelet decomposition is used to decompose the characteristic curve of the characters outer boundary, the feature matching is made and the offset of the curve about the template is obtained at low resolution, the outer boundary is adjusted in the initial resolution to complete the vehicle precise location. The actual coordinate of the block is determined combined with the height fixed of character, improves the distance of the vehicle traveling. In actual environment, it tests the algorithm for longer than two hours, and compared with coil speed and video speed measurement by license plate location. Results show that, under normal speed, the error is within 3 km/h compared with the coil speed.