Abstract: The license plate recognition system has been widely used in highway toll gate
and garage management of residential quarters, and license plate location is the precondition of
the realization of the whole recognition system. The effects of localization methods based on
gray-scale image and color-plate image are not ideal. By making full use of the license plate of a
priori information, a method of license plate location based on the HSV color space and
mathematical morphology is proposed. First, get the possible objects by using color information
as a filter, then generate connected regions by using mathematical morphology techniques and
generate the final correct license plate region, and last use radon transform to tilt correction.

Key words: license plate location, HSV color space, mathematical morphology, radon
transform