| 摘要 |
PROBLEM TO BE SOLVED: To provide a number plate position detector capable of highly accurately detecting the position of a number plate even from an image in which the outline of a plate or a character area can not be easily judged. SOLUTION: When a distance from an automobile 4 is included within a prescribed range, a CCD camera 1 photographs a picture of the automobile 4, an A/D converter 2 converts an image signal 11 into a digital image and a plate position detecting means segments a small area from the original image (segmenting processing). Then the contour part of a pattern existing in the small area is emphasized (edge emphasis processing) and the size of the edge- emphasized image is compressed (compression processing). The compressed pattern is inputted to a learned neural network and an output value is calculated (output value calculation processing). The output value is coordinate-transformed to an original image scale (coordinate transformation processing), the coordinate- transformed data are multiplied by a Gaussian window in each point and these window-multiplied data are mutually added (adding processing). Similar processing is applied to plural different small areas and a small area of which projected addition value is maximum is judged as a number plate position. |
