| 摘要 |
A marking process used to mark an image on a substrate, such as a photographic marking process, a lithographic marking process, an ink-jet marking process, a line-on-line xerographic marking process or a rotated-screen xerographic marking process, is automatically detected using at least one image spatial characteristic obtained from image information picked up from the image. The at least one spatial characteristic, which is unique to the type of marking process, is obtained, for example, by generating an image power spectrum and analyzing the power spectrum according to the existence, position, and/or color of spectral peaks, and/or the existence or absence of abnormally high energy at the high frequencies in the power spectrum.
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