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Automated license plate recognition system and method using human-in-the-loop based adaptive learning

  • US 9,092,979 B2
  • Filed: 12/14/2010
  • Issued: 07/28/2015
  • Est. Priority Date: 12/14/2010
  • Status: Active Grant
First Claim
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1. A method for automatically recognizing a license plate character sequence of a license plate of an automotive vehicle, said method comprising:

  • training a recognition algorithm associated with a license plate optical character recognition engine by adjusting recognition algorithm parameters based on a training data set comprising variations in training data license plate images and corresponding training data ground truth license plate character sequences;

    segmenting at least one image of an automotive vehicle to determine a license plate image of a license plate located on said automotive vehicle within a scene;

    determining an automatically recognized license plate character sequence in said license plate image utilizing said license plate optical character recognition engine;

    generating a confidence level for said automatically recognized license plate character sequence with respect to said license plate image, wherein said confidence level is based on a signal-to-noise ratio in said license plate image and other image artifact quantifications;

    comparing said confidence level to a lower limit;

    routing said license plate image to a human operator if said confidence level is below said lower limit;

    obtaining a human interpreted license plate character sequence from a human operator after said human operator examines said license plate image; and

    adjusting at least one parameter of said recognition algorithm associated with said license plate optical character recognition engine based on said human interpreted license plate character sequence and said license plate image in order to automatically recognize said license plate character sequence of said license plate of said automotive vehicle in a wide range of transportation applications.

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