发明授权
US06476936B1 Method for scanning screened image master images 失效
扫描图像主图像的方法

  • 专利标题: Method for scanning screened image master images
  • 专利标题(中): 扫描图像主图像的方法
  • 申请号: US09403671
    申请日: 1999-12-07
  • 公开(公告)号: US06476936B1
    公开(公告)日: 2002-11-05
  • 发明人: Jörg Olaf Von Wechgeln
  • 申请人: Jörg Olaf Von Wechgeln
  • 优先权: DE19706160 19970217
  • 主分类号: H04N100
  • IPC分类号: H04N100
Method for scanning screened image master images
摘要:
A method for opto-electronic scanning, by pixel and by line, of screened master photographic images with a sensing device. From the actual scanning, at least one master photographic image area that contains the grid scale is detected in the screened master photographic image. Subsequently, the picture values present in the local area of the detected grid scale area of the master photographic image are transferred by Fourier transformation to the frequency range as a spatial frequency spectrum, and, from the spatial frequency spectrum, the screen ruling and raster angle of the raster of the master photographic image are determined. For the determined raster angle and the determined screen rulings of the grid scale of the master photographic image, the optimal scan frequencies for Moiré-free scanning are determined from the spatial frequency spectrum. The optimal scan frequencies which determined the scanning fineness are set at the sensing device and then the screened master photographic image is scanned with the set optical scan frequencies, to obtain the picture values necessary for reproduction of the screened master photographic image.
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