摘要 |
Collation Fourier image data (FIG. 1D) FB generated by performing the two-dimensional discrete Fourier transform (DFT) for the image data (FIG. 1C) of a collation pattern is synthesized with registration Fourier image data (FIG. 1B) generated by performing the two-dimensional DFT for the image data of a registration pattern. After amplitude suppression processing is performed for the resultant data, two-dimensional DFT is performed. A correlation peak is extracted from a correlation component area which appears in the synthesized Fourier image data (FIG. 1E) for which the two-dimensional DFT has been performed. A predetermined area including this correlation peak is then masked (FIG. 1F). The two-dimensional DFT is performed for the masked synthesized Fourier image data, and amplitude restoration processing is performed for the data. The resultant data is re-synthesized with the registration Fourier image data FA, and the two-dimensional IDFT is performed for the synthesized data. With this processing, image data containing a difference pattern like the one shown in FIG. 1G or a moving pattern can be obtained.
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