Halftone patterns
First Claim
Patent Images
1. A screen system having:
- a plurality of screens each representing different colours or black in a digital original image, each screen has a pattern of printing areas which defines a minimum mesh, each pattern has a parcel of printing areas which repeats throughout the respective screen, and two or more of the screens have different non-orthogonal minimum meshes and have parcels which correspond in shape and size, said two or more screens having different non-orthogonal minimum meshes have printing areas which extend to join first along directions other than that of their closest spacing and;
a processor arrangement configured to take as input the digital original image and to generate, using the plurality of screens, a coloured halftone image.
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Accused Products
Abstract
The patterns can be used to reduce one or more undesirable effects such as moire or colour shift in coloured halftone images. Colour screens in the images are based on a combination of non-orthogonal mesh structures with parcels of printing dots which have common shape and size. Preferably the dots grow in mid tones by extending first towards their second, third or fourth nearest neighbours.
22 Citations
18 Claims
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1. A screen system having:
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a plurality of screens each representing different colours or black in a digital original image, each screen has a pattern of printing areas which defines a minimum mesh, each pattern has a parcel of printing areas which repeats throughout the respective screen, and two or more of the screens have different non-orthogonal minimum meshes and have parcels which correspond in shape and size, said two or more screens having different non-orthogonal minimum meshes have printing areas which extend to join first along directions other than that of their closest spacing and; a processor arrangement configured to take as input the digital original image and to generate, using the plurality of screens, a coloured halftone image. - View Dependent Claims (2, 3, 4, 5, 6, 7, 17)
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8. A method of preparing halftone patterns for production of a coloured image, comprising:
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receiving information representing colour and tone variation in an image, creating a plurality of printing patterns which represent different colours or black in the image, forming each pattern from variable printing areas which define respective meshes and repeating parcels, at least two of the patterns having different non-orthogonal minimum meshes and corresponding parcels which are substantially similar in shape and size, said at least two patterns having printing areas which extend to join first along directions other than that of their closest spacing. - View Dependent Claims (9, 10, 11, 12, 18)
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13. A screen system having:
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a plurality of screens, each screen has a pattern of printing areas which defines a minimum mesh, the minimum meshes of at least two screens are non-orthogonal and have printing areas which extend to join first along directions other than that of their closest spacing and; a processor arrangement configured to take as input a digital original image and to generate, using the plurality of screens, a coloured halftone image. - View Dependent Claims (14)
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15. A method of preparing a halftone pattern, comprising:
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receiving information representing tone variation in an image, creating a pattern of printing areas which represents the variation by forming the pattern to define a non-orthogonal minimum mesh, and varying the printing areas by extension toward nearby areas other than their nearest neighbours. - View Dependent Claims (16)
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Specification