Dot pattern forming apparatus and set of FM screen threshold matrices
AssigneeFuji Photo Film Co., Ltd.
InventorMakoto Sugizaki
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Abstract
A continuous-tone image of uniform density and the thresholds in the FM screen threshold matrices are compared to form dot patterns for CKM-separations. When the dot patterns are transformed by FFT, frequency-domain data are obtained. The obtained frequency-domain data are substantially elliptical figures, and the directions of the major axes of the substantially elliptical figures differ from each other.
Claims20
A dot pattern forming apparatus for converting a continuous-tone image into binary dot patterns for color separations of a multiple color image by FM screen threshold matrices for the separations of the multiple color image,
- wherein when a middle tone image of uniform density is converted into the binary dot patterns for the separations of the multiple color image by the FM screen threshold matrices for the separations of the multiple color image, and when each of dot patterns for at least two separations in the converted binary dot patterns is FFTed from an image in spatial domain to a two-dimensional image in frequency domain, the transformed two-dimensional images for at least the two separations are substantially elliptical figures,
- each of the substantially elliptical figures includes an ellipse and a figure that is not a circle or a rectangle but is symmetrical with respect to straight lines of major and minor axes orthogonal to each other and that has a smooth curvature along the entire periphery of the figure, and
- the directions of the major axes of the substantially elliptical figures for at least the two separations differ from each other.
A dot pattern forming apparatus for converting a continuous-tone image into binary dot patterns for CMYK-separations by FM screen threshold matrices for the CMYK-separations,
- wherein when a middle tone image of uniform density is converted into the binary dot patterns for the CMYK-separations by the FM screen threshold matrices for the CMYK-separations, and when each of the converted binary dot patterns is FFTed from an image in spatial domain to a two-dimensional image in frequency domain, the transformed two-dimensional images for the CMYK-separations are substantially elliptical figures,
- each of the substantially elliptical figures includes an ellipse and a figure that is not a circle or a rectangle but is symmetrical with respect to straight lines of major and minor axes orthogonal to each other and that has a smooth curvature along the entire periphery of the figure, and
- the directions of the major axes of the substantially elliptical figures for the CMYK-separations differ from each other.
A set of FM screen threshold matrices for color separations of a multiple color image, for converting a continuous-tone image into binary dot patterns for the separations of the multiple color image,
- wherein when a middle tone image of uniform density is converted into the binary dot patterns for the separations of the multiple color image by the FM screen threshold matrices, and when each of dot patterns for at least two separations in the converted binary dot patterns is FFTed from an image in spatial domain to a two-dimensional image in frequency domain, the transformed two-dimensional images for at least the two separations are substantially elliptical figures,
- each of the substantially elliptical figures includes an ellipse and a figure that is not a circle or a rectangle but is symmetrical with respect to straight lines of major and minor axes orthogonal to each other and that has a smooth curvature along the entire periphery of the figure, and
- the directions of the major axes of the substantially elliptical figures for at least the two separations differ from each other.
A set of FM screen threshold matrices for CMYK-separations, for converting a continuous-tone image into binary dot patterns for the CMYK-separations,
- wherein when a middle tone image of uniform density is converted into the binary dot patterns for the CMYK-separations by the FM screen threshold matrices, and when each of the converted binary dot patterns is FFTed from an image in spatial domain to a two-dimensional image in frequency domain, the transformed two-dimensional images for the CMYK-separations are substantially elliptical figures,
- each of the substantially elliptical figures includes an ellipse and a figure that is not a circle or a rectangle but is symmetrical with respect to straight lines of major and minor axes orthogonal to each other and that has a smooth curvature along the entire periphery of the figure, and
- the directions of the major axes of the substantially elliptical figures for the CMYK-separations differ from each other.
Dependencies are inferred from the claim text.