METHOD FOR GENERATING RELIEF PRINTS

• US 20130330476A1
• Filed: 05/31/2013
• Published: 12/12/2013
• Est. Priority Date: 06/08/2012
• Status: Active Grant

• Current Assignee: Océ-Technologies B.V. (Canon Inc.)
• Original Assignee: Océ-Technologies B.V. (Canon Inc.)
• Inventors: KLEIN KOERKAMP, Koen J., PERVILL, Jacques C.E.
• Granted Patent: US 8,976,415 B2
• Time in Patent Office: Days
• US Class Current: 427/258
• CPC Class Codes: B05D 5/06 to obtain multicolour or other optical effects B05D5/02 takes precedence
• CPC Class Codes: B41F 33/0009 Central control units
• CPC Class Codes: H04N 1/54 Conversion of colour picture signals to a plurality of signals some of which represent particular mixed colours, e.g. for textile printing
• CPC Class Codes: H04N 1/60 Colour correction or control H04N1/54 takes precedence

Abstract

A method is provided for processing a rasterized relief image, comprising customary color channels for indicating a color of each pixel and a height channel for indicating a height of each pixel into several pass images that are printed using a printer with several colorants including a white colorant. For each pixel a relief part, a white part and a skin part are discriminated in order to combine the demands for height and color variation across the surface of the image. The skin part comprises pixels for which a colorant composition based on the color channels of the rasterized relief image is established. In order to print a color in the skin part that is independent of a height of the pixel and independent of the colorant composition of a neighboring pixels, pass images are composed that include only neighboring pass pixels that do not disturb the color forming of a pass pixel contributing to a skin part.

Claims

1. A method for generating a relief print on a substantially flat substrate (201), wherein palpable differences exist between a height of various parts of the relief print, by a printer (5) comprising a number of colorants including a white colorant, said printer being configured to print a relief print in a number of passes, the method comprising the steps of:

defining a rasterized relief image, comprising customary color channels for indicating a color of each pixel and a height channel for indicating a relative height of each pixel of the rasterized relief image;

determining a height parameter for establishing an absolute height scale;

discriminating in the rasterized relief image for each pixel from the substrate to the surface of the relief image a relief part (202), a white part (203) and a skin part (204);

deriving from the rasterized relief image a number of pass images (106) to be printed on top of each other, each pass image comprising pass pixels (103, 104, 105) for which a colorant composition is established based on a part of the pixel to which the pass pixel contributes;

printing said number of pass images by applying said established colorant composition on a position of the substrate (101) associated with a pixel in the relief image,

wherein the relief part comprises an arbitrary colorant composition, the white part comprises mainly white colorant and the skin part comprises colorants according to a color as defined in the color channels.

2. The method according to claim 1, wherein a pass pixel is selected for a pass image based on the distance of the pass pixel to the substrate.

3. The method according to claim 1, wherein a pass pixel that contributes to the skin part of a pixel in the relief image is selected for a pass image only if none of the neighboring pass pixels contributes to the white part of a corresponding pixel.

4. The method according to claim 1, wherein a pass pixel that contributes to the skin part of a pixel in the relief image is selected for a pass image only if a predetermined number of pass images have been established between said pass image and the pass image in which the white part of the pixel in the relief image has been finished.

5. The method according to claim 1, wherein the white part of a pixel in the relief image is printed in a predetermined number of pass images.

6. The method according to claim 1, wherein the composition of colorants in the skin part of a pixel is established by application of a color management module using the color channels of the relief image, independent of the height channel.

7. A computer program product, including computer readable code embodied on a computer readable medium, said computer readable code comprising instructions for executing the steps of:

receiving a rasterized relief image, comprising customary color channels for indicating a color of each pixel and a height channel for indicating a height of each pixel of the rasterized relief image;

discriminating in the rasterized relief image for each pixel from the substrate to the surface of the relief image a relief part, a white part and a skin part;

deriving from the rasterized relief image a number of pass images to be printed on top of each other, each pass image comprising pass pixels for which a colorant composition is established based on a part of the pixel to which the pass pixel contributes;

transferring said pass images to a print engine, that comprises a white colorant and is configured to print the pass images in a predetermined order by applying said established colorant composition on a position of the substrate associated with a pixel in the relief image,

wherein the relief part comprises an arbitrary colorant composition, the white part comprises mainly white colorant and the skin part comprises colorants according to a color as defined in the color channels.

8. A print system configured to generate relief prints on a substantially flat substrate in a number of passes, wherein palpable differences exist between a height of various parts of the relief print, the print system comprising a print controller and a print engine, the print engine comprising a number of colorants including a white colorant, the print controller comprising:

receiving means for receiving a rasterized relief image, comprising customary color channels for indicating a color of each pixel and a height channel for indicating a height of each pixel of the rasterized relief image;

discriminating means for discriminating in the rasterized relief image for each pixel from the substrate to the surface of the relief image a relief part, a white part and a skin part;

deriving means for deriving from the rasterized relief image a number of pass images to be printed on top of each other, each pass image comprising pass pixels for which a colorant composition is established based on a part of the pixel to which the pass pixel contributes;

transferring means for transferring said pass images to the print engine, that is configured to print said number of pass images in a predetermined order by applying said established colorant composition on a position of the substrate associated with a pixel in the relief image,

wherein the relief part comprises an arbitrary colorant composition, the white part comprises mainly white colorant and the skin part comprises colorants according to a color as defined in the color channels.