Matlab project to recognize license plate of vehicles

I am working on a project with a team to detect license plate in the image, and recognize the characters (character extraction). The image will be the front view of the vehicle. The problem I am stuck in is with the Algorithms I am using. I am utilizing both linear discriminate analysis and PCA methods. In both, for some vehicles I am getting the stickers or labels the drivers stick to the car. Is there any algorithm other than the mentioned which is used widely? One typical problem again here is license plates have no discipline in fonts. The size, alignment and shape of the characters, all are user defined here and hence the character recognition is also finding trouble. Amy guidance is highly appreciated.