Image analysis – Histogram processing – For setting a threshold
Patent
1986-05-05
1989-03-28
Boudreau, Leo H.
Image analysis
Histogram processing
For setting a threshold
382 22, 382 48, 382 57, 382 60, G06K 900
Patent
active
048171662
ABSTRACT:
A video camera produces an image of a license plate on a vehicle, and a scanning apparatus finds a license plate number in the image. The identification of the license plate number is verified in a confidence check section by checking for the presence of a state logo. Next, a character extractor identifies individual characters of the number by finding and tracing a contour along interior portions of the character edges, and the contour length, character height, and character width are then checked in a validity checking section to determine whether they are within predetermined acceptable ranges. To correct for obscuring objects on the license plate, a character alignment section determines the top line and baseline of the license plate number and disregards portions of the characters that appear to be outside of these limits, and a license plate frame correction section is utilized to extract the characters when a portion thereof is obscured by a license plate frame. Once extracted, the characters are recognized by a structural analysis section and a state recognition section recognizes the state logo. Once the state is identified, a verification section rereads the license plate number utilizing knowledge of the type style used by the identified state.
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Gonzalez Rafael C.
Herrera Juan A.
Boudreau Leo H.
Perceptics Corporation
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