Halftone calibration mechanism

Patent metadata

Field	Value
Publication number	US-9785873-B2
Application number	US-201615044355-A
Country	US
Kind code	B2
Filing date	Feb 16, 2016
Priority date	Feb 16, 2016
Publication date	Oct 10, 2017
Grant date	Oct 10, 2017

Abstract

A printing system is disclosed. The printing system includes a halftone calibration module to receive one or more un-calibrated halftones, transform un-calibrated threshold values in the one or more un-calibrated halftones via an inverse transfer function to generate calibrated halftone threshold values and generate one or more calibrated halftones based on the calibrated halftone threshold values.

First claim

What is claimed is:

1. An article of manufacture comprising a non-transitory machine-readable medium including data that, when accessed by a machine, cause the machine to:
generate an inverse transfer function for each of a plurality of gray levels based on a target response and a measured response;
receive one or more un-calibrated halftones;
transform un-calibrated threshold values in the one or more un-calibrated halftones via the inverse transfer function to generate calibrated halftone threshold values;
generate one or more calibrated halftones based on the calibrated halftone threshold values;
process image data using the one or more calibrated halftones; and
transmit the processed image data for printing.

2. The article of manufacture of claim 1 , wherein generating the inverse transfer function comprises:
defining a highest achievable gray level;
calculating a value a magnitude less than the highest gray level; and
determining the inverse transfer function from the target response and the measured response.

3. The article of manufacture of claim 2 , comprising a machine-readable medium including data that, when accessed by a machine, further cause the machine to process one or more un-calibrated threshold arrays including the un-calibrated threshold values using the inverse transfer function to generate one or more calibrated threshold arrays having the calibrated halftone values.

4. The article of manufacture of claim 3 , comprising a machine-readable medium including data that, when accessed by a machine, further cause the machine to compare image data to values in the one or more calibrated threshold arrays for each of one or more planes.

5. The article of manufacture of claim 4 , wherein each of the one or more planes define thresholds for a drop size.

6. The article of manufacture of claim 5 , wherein the one or more planes comprise at least one of a Large drop size, Medium drop size, Small drop size and None.

7. The article of manufacture of claim 6 , comprising a machine-readable medium including data that, when accessed by a machine, further cause the machine to process non-single values in the one or more calibrated threshold arrays.

8. The article of manufacture of claim 3 , wherein the one or more un-calibrated threshold arrays and the one or more calibrated threshold arrays comprise multi-bit threshold arrays.

9. The article of manufacture of claim 1 , wherein the inverse transfer function is derived from a corresponding transfer function.

10. The article of manufacture of claim 1 , comprising a machine-readable medium including data that, when accessed by a machine, further cause the machine to print the processed image data.

11. A printing system comprising:
a controller operable to generate an inverse transfer function for each of a plurality of gray levels based on a target response and a measured response, receive one or more un-calibrated halftones, transform un-calibrated threshold values in the one or more un-calibrated halftones via an inverse transfer function to generate calibrated halftone threshold values, generate one or more calibrated halftones based on the calibrated halftone threshold values, process image data using the one or more calibrated halftones and transmit the processed image data for printing.

12. The printing system of claim 11 wherein generating the inverse transfer function comprises defining a highest achievable gray level, calculating a value a magnitude less than the highest gray level and determining the inverse transfer function from a target response and a measured response.

13. The printing system of claim 12 wherein the controller is operable to process one or more un-calibrated threshold arrays including the un-calibrated threshold values using the inverse transfer function to generate one or more calibrated threshold arrays having the calibrated halftone values.

14. The printing system of claim 13 wherein the controller is operable to compare image data to values in the one or more calibrated threshold arrays for each of one or more planes.

15. The printing system of claim 14 wherein each of the one or more planes define thresholds for a drop size.

16. The printing system of claim 15 wherein the one or more planes comprise at least one of a Large drop size, Medium drop size, Small drop size and None.

17. The printing system of claim 16 wherein the controller is operable to process non-single values in the one or more calibrated threshold arrays.

18. The printing system of claim 13 wherein the one or more un-calibrated threshold arrays and the one or more calibrated threshold arrays comprise multi-bit threshold arrays.

19. The printing system of claim 11 wherein the inverse transfer function is derived from a corresponding transfer function.

20. The printing system of claim 11 , further comprising a printer to print the processed image data.

Assignees

• Stanich Mikel
• Gurudath Nikita
• Ernst Larry M
• Manchester William E
• Ricoh Co Ltd

Inventors

• Stanich Mikel
• Gurudath Nikita
• Ernst Larry M
• Manchester William E

Classifications

• G06K15/1881 Primary

  Halftoning (halftoning of still images in general H04N1/405, H04N1/52) · CPC title

• H04N1/4057 Primary

  the pattern being a mixture of differently sized sub-patterns, e.g. spots having only a few different diameters (multi-toning H04N1/40087) · CPC title