| 摘要 |
PURPOSE:To provide a method and device for license plate area determination which can securely determine the area with a small detection error. CONSTITUTION:An edge detecting circuit 1 detects longitudinal edge intensity information from a video signal obtained by picking up an image of a specific range including a license plate mounted on a vehicle, an opposite edge search and arithmetic circuit 3 calculates width information from the product of added longitudinal edge intensity information of pieces of longitudinal edge information on both edges and opposition interval information found from the longitudinal edge intensity information, and a weighing arithmetic circuit 6 calculates the number of the pieces of width information corresponding to the longitudinal length of the license plate from the longitudinal/ lateral ratio of the license plate, the width information, and the added longitudinal edge intensity information. Then the added longitudinal edge intensity information within the range of the number of pieces of width information is weighted and the maximum value position in the weighted longitudinal edge intensity information within the range of the number of pieces of width information is regarded as center coordinates to find the lateral length of the license plate from the longitudinal length of the license plate and width direction information on the basis of the number of the pieces of width information, thereby determining the license plate area. |
