OPTIMIZING OPTICAL SCANNERS FOR DIGITAL WATERMARK DETECTION
First Claim
Patent Images
1. A method comprising:
- illuminating a substrate with a first LED, the first LED providing illumination in a red spectrum, in which the first LED provides illumination having a peak in a range between 630 nm-710 nm;
illuminating the substrate with a second LED, the second LED providing illumination in a blue spectrum, in which the second LED provides illumination having a peak in a range between 410 nm-490 nm;
illuminating the substrate with a third LED, the third LED providing illumination in a green spectrum, in which the third LED provides illumination having a peak in a range between 500 nm-565 nm;
capturing imagery with a first 2D monochrome image sensor, in which the captured imagery comprises a first image capture corresponding to illumination by the first LED and the second LED, minus a second image capture corresponding to illumination by the third LED, in which the first image capture comprises data representing a cyan channel and a yellow channel, with each of the cyan channel and the yellow channel comprising a digital watermark embedded therein at a first signal polarity, and in which the captured imagery comprises a second image capture comprises data representing a magenta channel, the magenta channel comprising a digital watermark embedded therein at a second signal polarity that is inversely related to the first signal polarity.analyzing the captured imagery with a digital watermark detector to detect a digital watermark.
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Abstract
The present disclosure relates generally to digital watermarking for retail product packaging. A digital watermark can be carried in different color channels, and at with different signal polarities. Detection can utilize different illumination sources or image sensors with various filters to highlight signal in one or more of the channels.
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Citations
4 Claims
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1. A method comprising:
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illuminating a substrate with a first LED, the first LED providing illumination in a red spectrum, in which the first LED provides illumination having a peak in a range between 630 nm-710 nm; illuminating the substrate with a second LED, the second LED providing illumination in a blue spectrum, in which the second LED provides illumination having a peak in a range between 410 nm-490 nm; illuminating the substrate with a third LED, the third LED providing illumination in a green spectrum, in which the third LED provides illumination having a peak in a range between 500 nm-565 nm; capturing imagery with a first 2D monochrome image sensor, in which the captured imagery comprises a first image capture corresponding to illumination by the first LED and the second LED, minus a second image capture corresponding to illumination by the third LED, in which the first image capture comprises data representing a cyan channel and a yellow channel, with each of the cyan channel and the yellow channel comprising a digital watermark embedded therein at a first signal polarity, and in which the captured imagery comprises a second image capture comprises data representing a magenta channel, the magenta channel comprising a digital watermark embedded therein at a second signal polarity that is inversely related to the first signal polarity. analyzing the captured imagery with a digital watermark detector to detect a digital watermark.
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2. An method comprising:
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obtaining an image sensor by providing rows and columns of photo-sensors, and overlaying a first set of photo-sensors with a first set of green filters, and overlaying a second set of photo-sensors with a first set of magenta filters, in which for at least four co-located blocks of photo-detectors, there are two magenta filters diagonally arranged, and two green filters diagonally arranged within each 2×
2 block of photo-detectors;capturing image data with the image sensor; processing the captured image by subtracting image data captured by the first set of photo-detectors from image data captured by the second set of photo-detectors, said processing yielding processed image data; and analyzing the processed image data to detect a digital watermark therein.
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3. A method comprising:
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obtaining an image sensor by providing rows and columns of photo-sensors, and overlaying a first set of photo-sensors with a first set of green filters, and overlaying a second set of photo-sensors with a first set of magenta filters, in which for at least a 4×
4 block of photo-detectors, the first set of green filters comprises a 1;
3 ratio relative to the first set of magenta filters;capturing image data with the image sensor; processing the captured image by subtracting image data captured by the first set of photo-detectors from image data captured by the second set of photo-detectors, said processing yielding processed image data; and analyzing the processed image data to detect a digital watermark therein.
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4. A method comprising:
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obtaining an image sensor by providing rows and columns of photo-sensors, and overlaying a first set of photo-sensors with a first set of green filters, and overlaying a second set of photo-sensors with a first set of magenta filters, in which for at least four co-located blocks of 2×
2 photo-detectors, there are three magenta filters arranged, per 1 green filter within each 2×
2 block of photo-detectors;capturing image data with the image sensor; processing the captured image by subtracting image data captured by the first set of photo-detectors from image data captured by the second set of photo-detectors, said processing yielding processed image data; and analyzing the processed image data to detect a digital watermark therein.
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Specification