摘要 |
PROBLEM TO BE SOLVED: To provide a rotating angle detection error reducing method for highly accurately detecting the rotating angle of a source image pattern with low image resolution or detecting the rotating angle of a pattern limiting the spatial frequency, that the pattern has, to a low frequency band. SOLUTION: A source image is rotated at an arbitrary rotating angle, the rotating angle of a detection target pattern is detected from the rotated image by various rotating angle detecting methods, and the rotating angle of the pattern of the source image with a detection error is calculated by subtracting the arbitrary rotating angle from the detected rotating angle. Further, the same operation is repeated plural times while changing the arbitrary rotating angle, the rotating angle detection error is canceled by averaging the calculated plural rotating angles, and the rotating angle of the pattern of the source image is accurately found. Namely, the rotating angle of the source image is accurately detected by using a statistic character that the mean value of the detection error, which is included when the rotating angle of the arbitrarily rotated object pattern is detected, is converged to a fixed value including '0'.
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