Recursive halftoning and gray value substitution

Patent metadata

Field	Value
Publication number	US-10362194-B2
Application number	US-201515545712-A
Country	US
Kind code	B2
Filing date	Feb 27, 2015
Priority date	Feb 27, 2015
Publication date	Jul 23, 2019
Grant date	Jul 23, 2019

Abstract

An example system in accordance with an aspect of the present disclosure includes a halftone engine and a gray value engine. The halftone engine is to apply halftoning to an image recursively across a plurality of levels of image scales and spatial resolutions, to generate a pattern that is at least quasi-periodic across the plurality of levels. The gray value engine is to substitute gray values recursively for at least a portion of the halftoning.

First claim

What is claimed is:

1. A computing system comprising:
a halftone engine to apply halftoning to an input image to obtain a halftone image for a current level;
a gray value engine to substitute gray values for at least a portion of the halftone image to obtain a gray value image for the incremented level; and
a scaling engine to scale the gray value image to obtain a scaled image to serve as the input image for the halftone image at the incremented level;
wherein the computing system is to recursively iterate applying halftoning, substituting gray values, and scaling for a plurality of levels, and
wherein the computing system is to generate and output a pattern that is at least quasi-periodic and encodes a particular data payload at each of a plurality of different resolutions corresponding to the plurality of levels, the pattern being optically machine-readable to recover the corresponding data payload at each of the different resolutions.

2. The computing system of claim 1 , further comprising a stegatone engine to encode at least one payload across a plurality of levels of the halftone image, to recursively generate a multiscale stegatone.

3. The computing system of claim 2 , wherein the stegatone engine is to encode the at least one payload based on circular coding.

4. The computing system of claim 1 , wherein the halftone engine is to replace a halftone cell with a cell image.

5. The computing system of claim 1 , wherein the halftone engine is to identify the plurality of levels to include a level and associated spatial resolution corresponding to a spatial resolution capability of a printer to print the pattern.

6. The computing system of claim 1 , wherein, for a given level, the gray value engine is to replace a white value of the halftone image with a gray value not greater than 50%, and replace a black value of the halftone image with a gray value not less than 50%.

7. The computing system of claim 1 , wherein the scaling engine is to scale the gray value image according to a scale factor based on pixel replication.

8. The computing system of claim 1 , further comprising an image-based range finder, the image-based range finder comprising:
an optical system; and
a range finder target, the target comprising the pattern to be placed at a location for which range measurement is to be determined using the optical system to read the data payload from the pattern at a resolution corresponding to the range between the optical system and range finder target.

9. The computing system of claim 8 , wherein the pattern comprises a multiscale stegatone.

10. The computing system of claim 1 , wherein the pattern comprises a bitonal image.

11. The computing system of claim 1 , the computing system to encode a data payload into the pattern using circular coding.

12. The computing system of claim 1 , the halftoning engine to replace a halftone cell with an entire copy of the input image.

13. A method, comprising:
applying, by a halftone engine, halftoning to an image recursively across a plurality of levels of image scales and spatial resolutions, to generate a pattern that is at least quasi-periodic across the plurality of levels;
substituting, by a gray value engine, gray values recursively for at least a portion of the halftoning; and
outputting the pattern that is at least quasi-periodic and encodes a particular data payload at each of a plurality of different resolutions corresponding to the plurality of levels, the pattern being optically machine-readable to recover the corresponding data payload at each of the different resolutions.

14. The method of claim 13 , further comprising encoding, by a stegatone engine, at least one payload across the plurality of levels of the image, to generate a multiscale stegatone.

15. The method of claim 13 , further comprising encoding a plurality of different payloads across the plurality of levels.

16. The method of claim 13 , further comprising encoding the payload based on applying perturbations to the halftone image, wherein the quasi-periodic nature of the pattern is preserved between levels, despite the non-periodic perturbations contained in a given level.

17. The method of claim 13 , further comprising optically detecting a distance to the image based on visually identifying the pattern at a given level across the plurality of levels, and range finding according to a given range of distances corresponding to the given level.

18. A non-transitory machine-readable storage medium encoded with instructions executable by a computing system that, when executed, cause the computing system to:
apply, by a halftone engine, halftoning to an input image to obtain a halftone image for a current level;
substitute, by a gray value engine, gray values for at least a portion of the halftone image to obtain a gray value image for an incremented level;
scale, by a scaling engine, the gray value image to obtain a scaled image to serve as the input image for the halftone image at the incremented level;
recursively iterate the applying, encoding, incrementing, substituting, and scaling for a plurality of levels, to generate a pattern that is at least quasi-periodic across the plurality of levels; and
output the pattern that is at least quasi-periodic and encodes a particular data payload at each of a plurality of different resolutions corresponding to the plurality of levels, the pattern being optically machine-readable to recover the corresponding data payload at each of the different resolutions.

19. The storage medium of claim 18 , further comprising instructions that cause the computing system to encode the at least one payload based on circular coding and applying non-periodic perturbations to the halftone image.

20. The storage medium of claim 18 , further comprising instructions that cause the computing system to encode, by a stegatone engine, a payload for the current level of the halftone image.

Assignees

• Hewlett Packard Development Co

Inventors

• Ulichney Robert
• Gaubatz Matthew D
• Pollard Stephen

Classifications

• H04N1/4055 Primary

  producing a clustered dots or a size modulated halftone pattern · CPC title

• H04N1/52

  Circuits or arrangements for halftone screening · CPC title

• H04N1/6022 Primary

  Generating a fourth subtractive colour signal, e.g. under colour removal, black masking · CPC title

• H04N2201/0082

  Image hardcopy reproducer (H04N2201/0091 - H04N2201/0094 take precedence) · CPC title