COLORING OF THREE-DIMENSIONAL PRINTED OBJECTS

• US 20160339643A1
• Filed: 01/26/2015
• Published: 11/24/2016
• Est. Priority Date: 01/26/2014
• Status: Active Grant

• Current Assignee: Stratasys Incorporated
• Original Assignee: Stratasys Incorporated
• Inventors: DIKOVSKY, Daniel, SHTILERMAN, Stanislav, BRESSLER, Yoav
• Granted Patent: US 10,363,729 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B29C 64/106 using only liquids or viscous materials, e.g. depositing a continuous bead of viscous material
• CPC Class Codes: B29C 64/112 using individual droplets, e.g. from jetting heads
• CPC Class Codes: B29C 64/386 Data acquisition or data processing for additive manufacturing
• CPC Class Codes: B33Y 10/00 Processes of additive manufacturing
• CPC Class Codes: B33Y 30/00 Apparatus for additive manufacturing; Details thereof or accessories therefor
• CPC Class Codes: B33Y 50/02 for controlling or regulating additive manufacturing processes
• CPC Class Codes: B41M 5/0082 Digital printing on bodies of particular shapes sublimation or volatilisation of pre-printed design B41M5/035
• CPC Class Codes: H04N 1/60 Colour correction or control H04N1/54 takes precedence
• CPC Class Codes: H04N 1/6011 with simulation on a subsidiary picture reproducer H04N1/622 takes precedence; matching two or more picture reproducers H04N1/6052

Abstract

A method of printing a three-dimensional (3D) color object, layer-by-layer, comprises: obtaining a 3D CAD specification defining a 3D geometry and a surface color distribution for the color object to be printed, defining regions on a surface of the color object; defining colors for each region based on the CAD specification; determining, using the 3D geometry of the specification, conditions applying at respective regions that are liable to cause color variation, such that using the colors as defined at the respective regions may give rise to a coloration error; selecting color corrections defined for respective determined conditions; correcting the defined colors; and printing the 3D color object with the color corrections.

Claims

1. A method of printing a three-dimensional (3D) color object, layer-by-layer, the method comprising:

obtaining a 3D CAD specification defining a 3D geometry and a surface color distribution for said color object;

defining regions on a surface of said color object;

defining colors for each region based on said surface color distribution;

determining, using said 3D geometry, conditions applying at respective regions that are liable to cause color variation, such that using said colors as defined at said respective regions may give rise to a coloration error;

selecting color corrections defined for respective determined conditions;

correcting said defined colors using said defined corrections, to compensate for respectively corresponding coloration errors; and

printing said 3D color object using respective corrected defined colors at each region.

2. The method of claim 1, wherein said color is printed over surface pixels and said conditions comprise colors in neighboring pixels.

3. The method of claim 1, wherein said color corrections are obtained from a look up table.

4. The method of claim 2, wherein said object is printed using a material having at least some transparency, color perception being defined by a depth into said surface, and each surface pixel being defined in terms of a predetermined number of voxels extending into said depth in a color stack, said condition being interference between different color stacks of neighboring 3D surfaces.

5. The method of claim 4, comprising obtaining said respective corrections from a look-up table defined for a corresponding color interference.

6. The method of claim 4, comprising obtaining said respective correction using a color change model.

7. The method of claim 4, comprising obtaining said respective correction using a dithering process between voxels of respectively interfering color stacks.

8. The method of claim 4, comprising generating different voxel combinations for respective pairs of interfering color stacks and finding a combination giving a least error with a design color.

9. The method of claim 8, wherein said finding a combination giving a least error comprises matching said respective different voxel combinations to find a combination requiring a minimal amount of voxel overwriting.

10. The method of claim 8, wherein said finding a combination giving a least error comprises placing least strong colors in voxel positions of maximal mutual interference.

11. The method of claim 1, wherein said conditions comprise one member of the group consisting of surface angle and surface position relative to other surfaces.

12. The method of claim 11, comprising obtaining said corrections from a look up table defined for said member.

13. The method of claim 1, comprising:

obtaining said corrections by printing a test 3D object under said conditions; and

tabulating measured color deviations against applied colors.

14. The method of claim 1, comprising:

obtaining said corrections by obtaining factors responsible for causing errors under predetermined conditions;

calculating errors using said obtained factors, and

tabulating said calculated errors against said conditions.

15. The method of claim 1, comprising:

detecting the presence of bright colors or colors of high luminance, and

in an event of such presence, applying as said corrections an outer layer of white and an underlying core of white on either side of a layer of said bright colors or colors of high luminance.

16. A three-dimensional (3D) color printer for printing 3D color objects layer-by-layer, the printer comprising:

a specification input for inputting a 3D CAD specification defining a 3D geometry and a surface color distribution for said color object;

a region definer for defining regions on a surface of said color object;

a color definer for defining colors for each region based on said surface color distribution;

an error determination unit for determining, using said 3D geometry, conditions applying at respective regions that are liable to cause color variation, such that using said colors as defined at said respective regions may give rise to a coloration error;

a selector, for selecting color corrections defined for respective determined conditions;

a corrector for correcting said defined colors using said defined corrections, to compensate for respectively corresponding coloration errors; and

said printer being configured to print said 3D color object using respective corrected defined colors at each region.