| 摘要 |
PROBLEM TO BE SOLVED: To stably remove moire fringes occurring in a pattern image as a recognition object, regardless of the direction, period, and regularity of the moire fringes.SOLUTION: A pattern image as a recognition object is subjected to two-dimensional Fourier transform, and a set of low-frequency components distributed in a center part of a resulting spectrum image B1 is extracted, and then a set of frequency components distributed to meet a preliminarily determined criterion is extracted from an area on the outside of the extracted set, as frequency components of noise. Further, a spectrum image B5 from which the frequency components of noise have been removed is generated on the basis of the extraction result (image B4) of noise, and the image B5 is subjected to two-dimensional inverse Fourier transform, whereby a pattern image from which noise has been removed is generated. |
