Patent ID: 6476936
Filing Date: 2002-11-05
Classification: H04N

Abstract:
Method for pixel-by-pixel and line-by-line opto-electronic scanning of screened image masters with a scanner device, characterized in that, before the actual scanning of the master,at least one master area (screen area) containing the screen is identified in the screened image master; the image values of the identified screen area of the image master present in the locus domain are converted by a Fourier transformation into the frequency domain as spatial frequency spectrum; screen width and screen angle of the screen of the image master are identified from the spatial frequency spectrum; the scan frequencies (fAx, fAy) from the spatial frequency spectrum that are optimum for a MoirÃ©-free scanning are determined for the identified screen angle and the identified screen width of the screen of the image master; the optimum scan frequencies (fAx, fAy) that determine the scan fineness are set at the scanner device; and the screened image master is scanned with the set, optimum scan frequencies (fAx, fAy) for acquiring the image values required for the reproduction of the screened image master.