Watermarking different areas of digital images with different intensities
First Claim
1. In a method of digitally watermarking an image by changing aspects thereof to steganographically convey a plural-bit payload, an improvement comprising:
- receiving image data representing a pattern of elements of differing spatial sizes but of uniform color;
applying a first filtering function to said image data to identify a first portion of the image represented thereby, said first portion comprising one or more regions having image elements within a first range of sizes;
applying a digital watermarking procedure to said first portion of the image using a first watermarking intensity;
applying a second filtering function to said image data to identify a second portion of the image represented thereby, said second portion comprising one or more regions having image elements within a second range of sizes;
applying a digital watermarking procedure to said second portion of the image using a second watermarking intensity greater than the first.
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Accused Products
Abstract
An image is processed to encode a digital watermark, with different regions thereof processed using different levels of watermark intensity. In an image comprised of elements of differing sizes (e.g., halftone shapes of different sizes, or lines of different width), the different regions can be defined by reference to the sizes of elements contained therein. Regions characterized by relatively small elements can be watermarked at a relatively low intensity. Regions characterized by relatively large elements can be watermarked at a relatively high intensity. A variety of other features are also discussed.
48 Citations
16 Claims
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1. In a method of digitally watermarking an image by changing aspects thereof to steganographically convey a plural-bit payload, an improvement comprising:
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receiving image data representing a pattern of elements of differing spatial sizes but of uniform color;
applying a first filtering function to said image data to identify a first portion of the image represented thereby, said first portion comprising one or more regions having image elements within a first range of sizes;
applying a digital watermarking procedure to said first portion of the image using a first watermarking intensity;
applying a second filtering function to said image data to identify a second portion of the image represented thereby, said second portion comprising one or more regions having image elements within a second range of sizes;
applying a digital watermarking procedure to said second portion of the image using a second watermarking intensity greater than the first. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. In a method of digitally watermarking a two-dimensional image by changing aspects thereof to steganographically convey a plural-bit payload, the image comprising a pattern of elements, an improvement comprising:
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defining a first two-dimensional mask, said first mask serving to identifying a first portion of the image, said first portion spanning plural of said elements;
defining a second two-dimensional mask, said second mask serving to identifying a second portion of the image, said second portion spanning plural of said elements;
watermarking the portion of the image identified by the first mask using a first watermarking intensity; and
watermarking the portion of the image identified by the second mask using a second, greater watermarking intensity. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16)
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Specification