Method and device for proofing raster print data while maintaining the raster information
AssigneeElectronics for Imaging, Inc.
InventorHolger Schuppan
Life of this patent
Estimating the term…
Abstract
The screened printing data are subjected to a filtering method, the raster information being maintained. Intermediate tonal values are produced by the filtering method, using the binary tonal values, the intermediate tonal values being configured in such a way that, by means of a color space transformation, transformed tonal values and/or intermediate tonal values can be formed which represent a true-to-color proof.
Claims8
Apparatus for proofing screened printing data while maintaining raster information having binary tonal values, the apparatus comprising:
- means for providing screened printing data;
- and
- means for filtering the screened printing data, wherein filtering comprises softening using a softening radius R that maintains the raster information and produces intermediate tonal values, wherein the softening radius R is determined by:
- a) calculating of a frequency distribution P(f) of a percentage area coverage f (0≦P≦1, 0≦f≦100%) for a predefined softening radius R=Ro;
- b) determining a percentage area coverage f0 at which P(f) is maximum;
- c) determining of a maximum value f1 and of a minimum value f2 with f1<f0<f2, for which P(f1)<P′ and P(f2)<P′(0<P′<1);
- d) if f2−f1≧Δf′ (0<Δf′<100%), then calculating of the frequency distribution P(f) for a softening radius increased by a predefined value ΔR;
- e) repeating of the steps b)-d) to determine the softening radius R at which f2−f1<Δf′, wherein the intermediate tonal values are configured such that, by means of a color space transformation, at least one of transformed tonal values and intermediate tonal values are formed which represent a true-to-color proof.
Apparatus for proofing screened printing data while maintaining the raster information having binary tonal values, the apparatus comprising:
- a means for filtering screened printing data while maintaining raster information, wherein an intermediate tonal value is produced by the filtering using a binary tonal value, and wherein the intermediate tonal value is such that, by means of a color space transformation, at least one of a transformed tonal value and an intermediate tonal value is formed which represent a true-to-color proof, and wherein the processor filters the screened printing data by softening the screened data using a softening radius R, which is determined by:
- a) calculating of a frequency distribution P(f) of a percentage area coverage f (0≦P≦1, 0≦f≦100%) for a predefined softening radius R=R0;
- b) determining a percentage area coverage f0 at which P(f) is maximum;
- c) determining of a maximum value f1 and of a minimum value f2 with f1<f0<f2, for which P(f1)<P′ and P(f2)<P′(0<P′<1);
- d) if f2−f1≧Δf′ (0<Δf′<100%), then calculating of the frequency distribution P(f) for a softening radius increased by a predefined value ΔR;
- e) repeating of the steps b)-d) to determine the softening radius R at which f2−f1<Δf′.
Dependencies are inferred from the claim text.