Assessment of camera phone distortion for digital watermarking
First Claim
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1. A method comprising:
- using one or more programmed electronic processors, quantifying distortion introduced by a cell phone camera, in which said act of quantifying distortion comprises quantifying a spatial frequency response (SFR) of the cell phone camera;
providing quantified distortion introduced by the cell phone camera as feedback to adjust a digital watermarking embedding process in view of the quantified distortion introduced by the cell phone camera, and in which adjustments are in terms of digital watermarking density or digital watermarking embedding strength; and
adjusting the digital watermarking embedding process in view of the quantified distortion introduced by the cell phone camera.
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Abstract
The present disclosure relates generally to cell phones and cameras, and to digital watermarking involving such cell phones and cameras. One claim recites a method comprising: measuring distortion introduced by a cell phone camera; using a programmed electronic processor, quantifying the distortion; and providing quantified distortion as feedback to adjust a digital watermark embedding process in view of the distortion introduced by the cell phone camera. The act of quantifying distortion may include, e.g., quantifying a spatial frequency response (SFR) of the cell phone camera. Of course, other claims and combinations are provided too.
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Citations
12 Claims
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1. A method comprising:
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using one or more programmed electronic processors, quantifying distortion introduced by a cell phone camera, in which said act of quantifying distortion comprises quantifying a spatial frequency response (SFR) of the cell phone camera; providing quantified distortion introduced by the cell phone camera as feedback to adjust a digital watermarking embedding process in view of the quantified distortion introduced by the cell phone camera, and in which adjustments are in terms of digital watermarking density or digital watermarking embedding strength; and adjusting the digital watermarking embedding process in view of the quantified distortion introduced by the cell phone camera.
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2. A method comprising:
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using one or more programmed electronic processors, quantifying distortion introduced by a cell phone camera;
providing quantified distortion introduced by the cell phone camera as feedback to adjust a digital watermarking process in view of the quantified distortion introduced by the cell phone camera, in which said act of quantifying distortion comprises quantifying a spatial frequency response (SFR) of the cell phone camera, in which quantifying the spatial frequency response (SFR) is determined by computing an area under the SFR curve for the range of spatial frequencies associated with a digital watermarking component and subtracting an area under the SFR curve due to aliasing; andadjusting the digital watermarking process in view of the quantified distortion introduced by the cell phone camera. - View Dependent Claims (3)
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4. A method comprising:
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measuring distortion introduced by a cell phone camera, in which said act of measuring distortion comprises quantifying a spatial frequency response (SFR) of the cell phone camera; using a programmed electronic processor, quantifying the distortion introduced by a cell phone camera, in which quantifying a spatial frequency response (SFR) is determined by;
λ
=ρ
synch−
ρ
alias,where ρ
synch is an area under a SFR curve in a region of an associated digital watermark component, and ρ
alias is an area under the SFR curve due to spatial frequencies aliasing with the digital watermark component; andproviding quantified distortion as feedback to adjust a digital watermarking process. - View Dependent Claims (5)
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6. A method comprising:
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measuring distortion introduced by a cell phone camera, in which said act of measuring distortion comprises analyzing a spatial frequency response (SFR) of the cell phone camera, and in which analyzing the spatial frequency response (SFR) comprises computing an area under a SFR curve for a range of spatial frequencies associated with a digital watermarking component and subtracting an area under the SFR curve due to aliasing; using a programmed electronic processor, quantifying the distortion; and providing quantified distortion as feedback to adjust a digital watermarking process in view of the distortion introduced by the cell phone camera. - View Dependent Claims (7, 9)
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8. A method comprising:
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measuring distortion introduced by a cell phone camera, in which said act of measuring distortion comprises analyzing a spatial frequency response (SFR) of the cell phone camera, and in which analyzing the spatial frequency response (SFR) comprises;
λ
=ρ
synch−
ρ
alias,where ρ
synch is an area under a SFR curve in a region of an associated digital watermarking component, and ρ
alias is an area under the SFR curve due to spatial frequencies aliasing with the digital watermark component;using a programmed electronic processor, quantifying the distortion; and providing quantified distortion as feedback to adjust a digital watermarking process.
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10. A system comprising:
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a cell phone comprising a camera; one or more processors programmed for; quantifying image distortion introduced by the cell phone camera, in which the quantifying image distortion comprises quantifying a spatial frequency response (SFR) of the cell phone camera, and in which the quantifying the spatial frequency response (SFR) comprises computing an area under a SFR curve for a range of spatial frequencies associated with a digital watermarking component and subtracting an area under the SFR curve due to aliasing; and providing quantified distortion as feedback to adjust digital watermarking in view of the image distortion introduced by the cell phone camera; and a digital watermarking module, which is configured to be adjusted in view of the quantified distortion introduced by the cell phone camera. - View Dependent Claims (11, 12)
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Specification