Method of embedding color information in printed documents using watermarking
AssigneeXerox Corporation
InventorsZhigang Fan, Shen-Ge Wang, Hui Cheng
Life of this patent
Estimating the term…
Abstract
A method for enhancing color fidelity in multi-reproduction, includes scanning an image to be reproduced, wherein the image contains an invisible digital watermark including color information; decoding the color information contained in the watermark; comparing the decoded color information with the scanned image; generating a correction table from the differences between the decoded color information and the scanned image; and performing color correction on the scanned image using the correction table. This method confines the color error to one generation, even when copies go through multiple reproduction.
Claims17
A method for enhancing color fidelity in multi-reproduction, comprising:
- scanning an image to be reproduced, wherein the image contains a digital watermark including color information;
- decoding the color information contained in the watermark;
- comparing the decoded color information with the scanned image;
- generating a correction table from the differences between the decoded color information and the scanned image;
- and
- performing color correction on the scanned image using the correction table.
A method for enhancing color fidelity in multi-reproduction, comprising:
- extracting color information from an original image;
- embedding and encoding the extracted color information in a digital watermark associated with the original image;
- printing a copy of the original image containing the digital watermark;
- scanning the printed image containing the digital watermark;
- decoding the color information contained in the watermark;
- comparing the decoded color information with the scanned image;
- generating a color-correction table from the differences between the decoded color information and the scanned image;
- and
- performing color correction on the scanned image using the correction table.
A method of extracting color information for use in a digital watermark, comprising:
- smoothing and sub-sampling an original image;
- sorting the samples into smooth samples and edge samples;
- quantizing pixel values of the smooth samples;
- and
- compressing the quantized pixel values of the smooth samples.
Dependencies are inferred from the claim text.