Character segmentation method for vehicle license plate recognition

A method for segmenting and recognizing license plates comprising the steps of:

• capturing an image of a license plate;
• preprocessing the image to prepare the image for segmentation and recognition;
• forward splitting regions of the license plate image into suspected characters regions by segmenting touching or overlapping characters in adjacent suspected character regions by employing a discrimination function based on contour projections of the characters, when the suspected characters have a confidence score below a threshold value;
• recognizing suspected character regions in the license plate image and providing a confidence score based on a probability of a correct match;
• if the suspected characters have a confidence score below a threshold value other than due to touching or overlapping characters, backward merging adjacent suspected character regions;
• recognizing the backward merged suspected character regions in the license plate;
• if the backward merged suspected character regions have a confidence score below the threshold value, repeating the backward merging and recognizing steps;
• comparing recognized characters and character blocks to predetermined license plate codes and conventions to check accuracy of recognition;
• and
• outputting recognized characters of the license plate image.

A program storage device readable by machine, tangibly embodying a program of instructions executable by the machine to perform method steps for segmenting and recognizing license plates, the method steps comprising:

• capturing an image of a license plate;
• preprocessing the image to prepare the image for segmentation and recognition;
• forward splitting regions of the license plate image into suspected characters regions;
• recognizing suspected character regions in the license plate image and providing a confidence score based on a probability of a correct match;
• if the suspected characters have a confidence score below a threshold value, backward merging adjacent suspected character regions;
• recognizing the backward merged suspected character regions in the license plate;
• and
• if the backward merged suspected character regions have a confidence score below the threshold value, repeating the backward merging and recognizing steps.