System and method of mitigating color offset discrepancies in 3D printing systems

1. A method of mitigating, by at least one processor, color discrepancies in a three-dimensional (3D) printing system comprising a plurality of printing heads, the method comprising:

obtaining a color offset vector from one or more samples;

receiving a model representing a 3D object, the model comprising a plurality of model printing points associated with respective color;

analyzing the model in view of the obtained color offset vector;

producing a calibrated data structure, adapted to mitigate color discrepancies, wherein producing the calibrated data structure comprises modifying the plurality of model printing points to comprise one or more of a transparent envelope region, a clarity enhancement region, a color compensation region and a white region; and

printing the 3D object according to the calibrated data structure.

2. The method according to claim 1 , wherein producing the calibrated data structure comprises defining the transparent envelope region comprising a plurality of printing points associated with a clear printing material, on an external surface of the model.

3. The method according claim 1 , wherein producing the calibrated data structure comprises:

calculating a compensated color ratio between two or more colors; and

defining a color compensation region, comprising a plurality of printing points, associated with the two or more colored materials at the compensated color ratio.

4. The method according to claim 1 , wherein producing the calibrated data structure comprises:

calculating an enhanced clarity ratio between a clear material and one or more colored materials; and

defining the clarity enhancement region, comprising a plurality of printing points, associated with one of the clear material and colored materials at the enhanced clarity ratio.

5. The method according to claim 1 , wherein producing the calibrated data structure further comprises defining the white region comprising a plurality of printing points of white color material, in a location adjacent to the clarity enhancement region.

6. The method according to claim 1 , further comprising:

producing a plurality of slice elements, corresponding to planar slices of the 3D object, wherein each slice comprises a plurality of slice printing points, and wherein each slice printing point is associated with a color of the calibrated data structure; and

for one or more slice printing points, applying a dithering algorithm on the calibrated data structure, to obtain a dithered value,

and wherein printing the 3D object further comprises selecting, for one or more slice printing points, a printing head, based on the dithered value.

7. The method according to claim 1 , wherein at least one sample of the one or more samples is a 3D sample, comprising a plurality of flat surfaces at specified spatial orientations, and wherein obtaining a color offset vector comprises:

measuring color of two or more of the plurality of flat surfaces;

calculating a color difference between measured colors; and

deriving the color offset from the calculated color difference.

8. The method according to claim 1 , wherein at least one sample of the one or more samples comprises a pattern of droplets of colored modeling material, and wherein obtaining a color offset vector comprises:

measuring a location of one or more droplets of the pattern of droplets;

calculating a color droplet misalignment according to the measured locations; and

deriving the color offset vector from the calculated droplet misalignment.

9. The method according to claim 1 , wherein calculating the compensated color ratio comprises, for one or more printing points of the color compensation region:

receiving a nominal color ratio;

calculating a base color compensation parameter, according to the color offset vector;

calculating a projection of a normal to a surface of the model on the color offset vector; and

calculating the compensated color ratio as a function of the base color compensation parameter, the nominal color ratio and the calculated projection.

10. The method according to claim 1 , wherein calculating the enhanced clarity ratio comprises, for one or more printing points of the clarity enhancement region:

receiving a nominal clarity ratio;

calculating a base clarity enhancement parameter, according to the color offset vector;

calculating a projection of a normal to a surface of the model on the color offset vector; and

calculating the enhanced clarity ratio as a function of the base clarity enhancement parameter, the nominal clarity ratio and the calculated projection.

11. A system for mitigating color discrepancies in a 3D printing system comprising a plurality of printing heads, the system comprising: a non-transitory memory device storing instruction code and a processor associated with the memory device, and configured to execute the instruction code, such that when the processor executes the instructions code, the processor is configured to:

obtain a color offset vector from one or more samples;

receive a model representing a 3D object, the model comprising a plurality of model printing points associated with respective color;

analyze the model in view of the obtained color offset vector to produce a calibrated data structure, adapted to mitigate color discrepancies by modifying the plurality of model printing points to comprise one or more of a transparent envelope region, a clarity enhancement region, a color compensation region and a white region; and

propagating the calibrated data structure to the 3D printing system so as to print a 3D object according to the calibrated data structure.

12. The system according to claim 11 , wherein the processor is further configured to produce the calibrated data structure by defining a transparent envelope region comprising a plurality of printing points associated with a clear printing material, on an external surface of the model.

13. The system according to claim 11 , wherein the processor is further configured to produce the calibrated data structure by:

calculating a compensated color ratio between two or more colors; and

defining the color compensation region, comprising a plurality of printing points, associated with the two or more colored materials at the compensated color ratio.

14. The system according to claim 11 , wherein the processor is further configured to produce the calibrated data structure by:

calculating an enhanced clarity ratio between a clear material and one or more colored materials; and

defining the clarity enhancement region, comprising a plurality of printing points, associated with one of the clear color and the one or more opaque colors at the enhanced clarity ratio.

15. The system according to claim 14 , wherein the processor is further configured to calculate the enhanced clarity ratio for one or more printing points of the clarity enhancement region by:

receiving a nominal clarity ratio;

calculating a base clarity enhancement parameter, according to the color offset vector;

calculating a projection of a normal to a surface of the model on the color offset vector; and

calculating the enhanced clarity ratio as a function of the base clarity enhancement parameter, the nominal clarity ratio and the calculated projection.

16. The system according to claim 11 , wherein the processor is further configured to produce the calibrated data structure by defining a white region comprising a plurality of printing points of white color, in a location adjacent to the clarity enhancement region.

17. The system according to claim 11 , wherein the processor is further configured to:

produce a plurality of slice elements, corresponding to planar slices of the 3D object, wherein each slice comprises a plurality of slice printing points, and wherein each slice printing point is associated with a color of the calibrated data structure; and

apply, for one or more slice printing points, a dithering algorithm on the calibrated data structure, to obtain a dithered value.

18. The system according to claim 11 , wherein at least one sample of the one or more samples is a 3D sample, comprising a plurality of flat surfaces at specified spatial orientations, and wherein the processor is further configured to obtain a color offset vector by:

measuring color of two or more of the plurality of flat surfaces;

calculating a color difference between measured colors; and

deriving the color offset from the calculated color difference.

19. The system according to claim 11 , wherein at least one sample of the one or more samples comprises a pattern of droplets of colored modeling material, and wherein the processor is further configured to obtain a color offset vector by:

measuring a location of one or more droplets of the pattern of droplets;

calculating a color droplet misalignment according to the measured locations; and

deriving the color offset vector from the calculated droplet misalignment.

20. The system according to claim 11 , wherein the processor is further configured to calculate the compensated color ratio for one or more printing points of the color compensation region by:

receiving a nominal color ratio;

calculating a base color compensation parameter, according to the color offset vector;

calculating a projection of a normal to a surface of the model on the color offset vector; and

calculating the compensated color ratio as a function of the base color compensation parameter, the nominal color ratio and the calculated projection.