Method and apparatus for recovering license plate information from an image

  • US 10,579,892 B1
  • Filed: 02/03/2015
  • Issued: 03/03/2020
  • Est. Priority Date: 06/27/2014
  • Status: Active Grant
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First Claim
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1. A mobile apparatus, comprising:

  • an image sensor configured to capture an optical image including an image of a vehicle license plate; and

    a license plate detector configured to;

    identify and crop, by a processor, one or more object images from the captured optical image with each of said one or more cropped object images comprising a candidate vehicle license plate image having a plurality of alphanumeric characters,score, by the processor, each of said cropped one or more object images based on a probability that the respective cropped object image comprises the vehicle license plate image, wherein each of the cropped one or more object images is scored by;

    providing a rectangular fitting around each character of the plurality of alphanumeric characters,fitting a line to a center of the respective rectangular fittings of each pair of the plurality of alphanumeric characters,for each fitted line, summing a distance of all other respective rectangular fittings to the respective fitted line,selecting the respective pair of alphanumeric characters corresponding to the respective fitted line with a smallest summed distance of all of the fitted lines as a text baseline for the candidate vehicle license plate image,computing a score for the candidate vehicle license plate image having the selected text baseline based at least on the rectangular fitting around each of the alphanumeric characters, relative positions of each of the alphanumeric characters relative to each other within the respective cropped object image and a calculated slope of the fitted line for the selected pair of alphanumeric characters, andrecover, by the processor, information relating to the vehicle license plate inresponse to the calculated score of the candidate vehicle license plate image confirming that the respective cropped object image corresponds to the vehicle license plate.

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