초록 ▼

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 ide

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.

대표청구항 ▼

An apparatus for finding and identifying an image of a license plate of a predetermined class that bears characters and that is mounted on a vehicles, comprising: means for producing an image that includes the license plate; means for scanning the image and identifying a block of the image that meet

An apparatus for finding and identifying an image of a license plate of a predetermined class that bears characters and that is mounted on a vehicles, comprising: means for producing an image that includes the license plate; means for scanning the image and identifying a block of the image that meets predetermined frequency that is above a selected non-zero threshold, said threshold being selected to correspond to the frequency expected to be produced by scanning across the characters of any license plate of the predetermined class; and decision means for comparing the block to second criteria to determine and indicate whether a block is an image of the license plate characters.