| 摘要 |
PROBLEM TO BE SOLVED: To extract a number plate even when data such as shadow to be easily erroneously recognized exist in an image by calculating the Y-axis projection of a differentiated value for which the differentiating processing of a multilevel image is performed from up to down in Y-axis direction. SOLUTION: The multilevel image stored in an image data storage part is extracted, initial setting is performed for setting the sampling position of that multilevel image and after the setting of the sampling position, the differentiating processing of these sampling positions is performed (S100 and S102). Y-axis projecting processing is performed for adding the values of differentiating processing in Y-axis direction and a peak value is calculated from Y-axis projection values (S104 and S106). After the peak value is once detected, when the value of Y-axis projection gets minimum, the position corresponding to that peak value means the position of the number plate. Namely, since the Y-axis projection including the number plate becomes maximum, the Y coordinate of the number plate is calculated from that position (S108 and S110).
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