Information coding and decoding in spectral differences
First Claim
Patent Images
1. A method for encoding an information signal in spectral differences within an image signal, the method comprising, with a programmed processor:
- generating an information signal comprising message symbols;
mapping the message symbols of the information signal to insertion locations within a host image signal; and
at the insertion locations, inserting the message symbols of the information signal by computing values for color components at the locations so as to form a spectral difference signal between ink applied at a first pixel location and ink applied at a second pixel location to encode a message symbol in relative spectral difference in spectral distribution between the ink at the first and second pixel locations, the computing encoding relative spectral differences at the locations that conveys the message symbols of the information signal within the host image, the spectral difference signal representing a distinguishable spectra between two or more colors that appear similar in the human visual system at the insertion locations within the host image signal.
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Abstract
Information is encoded in an image signal by exploiting spectral differences between colors that appear the same when rendered. These spectral differences are detected using image sensing that discerns the spectral differences. Spectral difference detection methods include using sensor-synchronized spectrally-structured-light imaging, 3D sensors, imaging spectrophotometers, and higher resolution Bayer pattern capture relative to resolution of patches used to convey a spectral difference signal.
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Citations
22 Claims
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1. A method for encoding an information signal in spectral differences within an image signal, the method comprising, with a programmed processor:
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generating an information signal comprising message symbols; mapping the message symbols of the information signal to insertion locations within a host image signal; and at the insertion locations, inserting the message symbols of the information signal by computing values for color components at the locations so as to form a spectral difference signal between ink applied at a first pixel location and ink applied at a second pixel location to encode a message symbol in relative spectral difference in spectral distribution between the ink at the first and second pixel locations, the computing encoding relative spectral differences at the locations that conveys the message symbols of the information signal within the host image, the spectral difference signal representing a distinguishable spectra between two or more colors that appear similar in the human visual system at the insertion locations within the host image signal. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A non-transitory computer readable medium, on which is stored instructions, which when executed on one or more processors, perform a method for encoding an information signal in spectral differences within an image signal, the method comprising:
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generating an information signal comprising message symbols; mapping the message symbols of the information signal to insertion locations within a host image signal; and at the insertion locations, inserting the message symbols of the information signal by computing values for color components at the locations so as to form a spectral difference signal between ink applied at a first pixel location and ink applied at a second pixel location to encode a message symbol in relative spectral difference between the ink at the first and second pixel locations, the computing encoding relative spectral differences at the locations that conveys the message symbols of the information signal within the host image, the spectral difference signal representing a distinguishable spectra between two or more colors that appear similar in the human visual system at the insertion locations within the host image signal.
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9. A method of decoding an information signal comprising, with a programmed processor:
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obtaining spectra of an image signal at locations within the image signal; discerning a spectral difference signal at the locations by determining, at the locations, a relative difference between spectral distributions at first and second pixel locations in the image signal, the spectral difference signal representing a distinguishable spectra between two or more colors that appear similar in the human visual system at the locations within the host image signal; and decoding an information signal from the spectral difference signal by extracting message symbols from relative differences between spectral distributions of different pixel locations and error correction decoding a message from the message symbols. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A non-transitory computer readable medium, on which is stored instructions, which when executed on one or more processors, perform a method of decoding an information signal, the method comprising:
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obtaining spectra of an image signal at locations within the image signal; discerning a spectral difference signal at the locations by determining, at the locations, a relative difference between spectral distributions at first and second pixel locations in the image signal, the spectral difference signal representing a distinguishable spectra between two or more colors that appear similar in the human visual system at the locations within the host image signal; and decoding an information signal from the spectral difference signal by extracting message symbols from relative differences between spectral distributions of different pixel locations and error correction decoding a message from the message symbols.
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22. An image capture device comprising:
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an illumination source in communication with a controller for providing controlled spectral illumination; an image capture sensor for capturing an image signal of an object or scene under the controlled spectral illumination; and one or more programmed processors configured to; obtain spectra of an image signal at locations within the image signal; discern a spectral difference signal at the locations by determining, at the locations, a relative difference between spectral distributions at first and second pixel locations in the image signal, the spectral difference signal representing a distinguishable spectra between two or more colors that appear similar in the human visual system at the locations within the host image signal; and decode an information signal from the spectral difference signal by extracting message symbols from relative differences between spectral distributions of different pixel locations and error correction decoding a message from the message symbols.
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Specification