Generation of halftone overlays for combination with halftoned images
First Claim
1. A method for rendering a composite image from a background image and an overlay image, wherein:
- said background image comprises background pixels, each having a background data level;
said overlay image comprises overlay pixels, each having an overlay data level;
said composite image comprises composite pixels, each having a composite data level;
comprising the steps of;
generating a composite data level for a composite pixel according to;
a spatially corresponding background data level if a spatially corresponding overlay pixel is not available; and
a spatially corresponding overlay data level if available;
rendering said composite image on an output medium as varying optical densities according to said composite data levels.
3 Assignments
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Accused Products
Abstract
The generation of personalised documents, or documents including variable data, may require one or more varying overlay images to be printed on top of a background image. In order to avoid the generation of the background image for each document separately, a method is provided to store the background image permanently and to merge it with the overlay images just before printing. A transparency notion may be introduced to avoid masking of the background image by horizontally oriented rectangular overlays. The overlay image and the background image may be generated by a process of multilevel halftoning, suitable for printing by an electrophotographic printing device, using colored toner.
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Citations
14 Claims
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1. A method for rendering a composite image from a background image and an overlay image, wherein:
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said background image comprises background pixels, each having a background data level; said overlay image comprises overlay pixels, each having an overlay data level; said composite image comprises composite pixels, each having a composite data level; comprising the steps of; generating a composite data level for a composite pixel according to; a spatially corresponding background data level if a spatially corresponding overlay pixel is not available; and a spatially corresponding overlay data level if available; rendering said composite image on an output medium as varying optical densities according to said composite data levels. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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Specification