Encoding printed grayscale images
AssigneeHewlett-Packard Development Company, L.P.
InventorsRobert Ulichney, Matthew D. Gaubatz
Life of this patent
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Abstract
In an example method, a dot pattern of pixels including information to be encoded across an image is mapped to a corresponding subset of the grayscale source pixels corresponding to the image to be printed. A value of a grayscale pixel in the subset of the grayscale source pixels is modified based on based on a predetermined threshold pixel value. The value of the grayscale pixel is decreased in response to detecting that the predetermined threshold pixel value is exceeded. The clipping channel color is used to detect the dot pattern of pixels. The image including the subset of pixels with modified values is printed.
Claims15
A method comprising:
- mapping a dot pattern of pixels comprising information to be encoded across an image to a corresponding subset of grayscale source pixels corresponding to the image;
- modifying a value of a grayscale pixel in the subset of the grayscale source pixels based on a predetermined threshold pixel value, wherein the value of the grayscale pixel is decreased in response to detecting that the predetermined threshold pixel value is exceeded;
- and
- printing the image comprising the subset of pixels with modified values.
An apparatus comprising:
- a receiver to receive a set of grayscale source pixels corresponding to an image to be printed and a dot pattern of pixels comprising information to be encoded across the image;
- a pattern mapper to map the dot pattern of pixels to a corresponding subset of the grayscale source pixels;
- a pixel modifier to modify a value of a grayscale pixel in the subset of the grayscale source pixels based on a predetermined threshold pixel value, wherein the value of the grayscale pixel is to be decreased in response to detecting that the predetermined threshold pixel value is exceeded;
- and
- a printer to print the image comprising the subset of pixels with modified values.
A non-transitory machine-readable storage medium encoded with instructions executable by a processor, the machine-readable storage medium comprising instructions to direct the processor to:
- receive a set of grayscale source pixels corresponding to an image to be printed and a dot pattern of pixels comprising information to be encoded across the image;
- map the dot pattern of pixels to a corresponding subset of the grayscale source pixels;
- modify a value of a grayscale pixel in the subset of the grayscale source pixels based on a predetermined threshold pixel value, wherein the value of the grayscale pixel is to be decreased in response to detecting that the predetermined threshold pixel value is exceeded;
- and
- print the image comprising the subset of pixels with modified values.
Dependencies are inferred from the claim text.