Watermarking different areas of digital images with different intensities

• US 7,697,716 B2
• Filed: 12/05/2005
• Issued: 04/13/2010
• Est. Priority Date: 09/01/1999
• Status: Active Grant

• Current Assignee: Digimarc Corporation
• Original Assignee: Digimarc Corporation
• Inventors: Miller, Marc D., Rodriguez, Tony F., Haaga, Donald
• Primary Examiner(s): KIM, CHONG R
• Application Number:
  US11/295,345
• Publication Number:
  US 20060140441A1
• Time in Patent Office: 1,590 Days
• Field of Search: None
• US Class Current: 382/100
• CPC Class Codes: G06T 1/0028 Adaptive watermarking, e.g. Human Visual System [HVS]-based watermarking
• CPC Class Codes: G06T 1/0092 Payload characteristic determination in a watermarking scheme, e.g. number of bits to be embedded
• CPC Class Codes: G06T 2201/0061 Embedding of the watermark in each block of the image, e.g. segmented watermarking
• CPC Class Codes: H04N 1/32203 Spatial or amplitude domain methods H04N1/32309 takes precedence
• CPC Class Codes: H04N 1/32208 involving changing the magnitude of selected pixels, e.g. overlay of information or super-imposition H04N1/32219, H04N1/32224 take precedence
• CPC Class Codes: H04N 1/32229 with selective or adaptive application of the additional information, e.g. in selected regions of the image H04N1/32213 takes precedence
• CPC Class Codes: H04N 1/32251 in multilevel data, e.g. greyscale or continuous tone data
• CPC Class Codes: H04N 1/32261 in binary data H04N1/32256 takes precedence

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.

Claims

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;

wherein the method includes performing said watermarking procedures using a computer that is programmed to perform said procedures pursuant to instructions from program software.

2. A method of processing a color image comprised of at least first and second color channel images, the method including performing the method of claim 1 on the first color channel image.

3. The method of claim 1 wherein said elements comprise halftone elements of varying sizes.

4. The method of claim 1 that includes printing said digitally watermarked image on a substrate to produce a printed document.

5. A printed document produced by the method of claim 4.

6. 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;

wherein if said first and second portions define a region of overlap, then applying a digital watermarking procedure to said overlap region using said first watermarking intensity rather than said second watermarking intensity; and

wherein the method includes performing said watermarking procedures using a computer that is programmed to perform said procedures pursuant to instructions from program software.

7. 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;

wherein said elements comprise lines of varying widths; and

wherein the method includes performing said watermarking procedures using a computer that is programmed to perform said procedures pursuant to instructions from program software.

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:

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;

wherein if said first and second masks define a portion of overlap, then watermarking said overlap portion using said first watermarking intensity rather than said second watermarking intensity; and

wherein the method includes performing said watermarking procedures using a computer that is programmed to perform said procedures pursuant to instructions from program software.

9. 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:

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;

wherein said elements comprise lines of varying widths; and

wherein the method includes performing said watermarking procedures using a computer that is programmed to perform said procedures pursuant to instructions from program software.

10. The method of claim 9 wherein;

the first portion of said image, identified by said first mask, includes regions of the image in which said lines have widths within a first range; and

the second portion of said image, identified by said second mask, includes regions of the image in which said lines have widths within a second range.

11. 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:

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;

wherein said elements comprise halftone elements of varying sizes; and

wherein the method includes performing said watermarking acts using a computer that is programmed to perform said watermarking acts pursuant to instructions from program software.

12. The method of claim 11 wherein;

the first portion of said image, identified by said first mask, includes regions of the image in which said halftone elements have sizes within a first range; and

the second portion of said image, identified by said second mask, includes regions of the image in which said halftone elements have sizes within a second range.

13. 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:

identifying a first portion of the image comprising elements having a first similar characteristic, said first portion spanning plural of said elements;

identifying a second portion of the image comprising elements having a second similar characteristic different than the first characteristic, said second portion spanning plural of said elements;

watermarking the first portion of the image using a first watermarking intensity; and

watermarking the second portion of the image using a second, greater watermarking intensity;

wherein the method includes performing said identifying and watermarking with a computer that is programmed to perform said acts pursuant to instructions from program software, and wherein the first similar characteristic comprises elements defining lines having a first range of widths, and the second similar characteristic comprises elements not defining lines having said first range of widths.

14. 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:

identifying a first portion of the image comprising elements having a first similar characteristic, said first portion spanning plural of said elements;

identifying a second portion of the image comprising elements having a second similar characteristic different than the first characteristic, said second portion spanning plural of said elements;

watermarking the first portion of the image using a first watermarking intensity; and

watermarking the second portion of the image using a second, greater watermarking intensity;

wherein the method includes performing said identifying and watermarking with a computer that is programmed to perform said acts pursuant to instructions from program software, and wherein the first similar characteristic comprises elements defining lines having a first range of widths, and the second similar characteristic comprises elements having a second, different, range of widths.

15. 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:

identifying a first portion of the image comprising elements having a first similar characteristic, said first portion spanning plural of said elements;

identifying a second portion of the image comprising elements having a second similar characteristic different than the first characteristic, said second portion spanning plural of said elements;

watermarking the first portion of the image using a first watermarking intensity; and

watermarking the second portion of the image using a second, greater watermarking intensity;

wherein the method includes performing said identifying and watermarking with a computer that is programmed to perform said acts pursuant to instructions from program software, and wherein the first similar characteristic comprises elements defining structures having a first range of sizes, and the second similar characteristic comprises elements not defining structures having said first range of sizes.

16. 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:

identifying a first portion of the image comprising elements having a first similar characteristic, said first portion spanning plural of said elements;

identifying a second portion of the image comprising elements having a second similar characteristic different than the first characteristic, said second portion spanning plural of said elements;

watermarking the first portion of the image using a first watermarking intensity; and

watermarking the second portion of the image using a second, greater watermarking intensity;

wherein the method includes performing said identifying and watermarking with a computer that is programmed to perform said acts pursuant to instructions from program software, and wherein the first similar characteristic comprises elements defining structures having a first range of sizes, and the second similar characteristic comprises elements having a second, different, range of sizes.

17. A computer readable storage medium having program software instructions stored thereon for causing a computer to perform acts including:

identify a first portion of a two-dimensional image that comprises elements having a first similar characteristic, said first portion spanning plural elements;

identify a second portion of the image that comprises elements having a second similar characteristic different than the first characteristic, said second portion also spanning plural elements;

steganographically watermark the first portion of the image using a first watermark intensity; and

steganographically watermark the second portion of the image using a second, greater watermark intensity;

wherein the first similar characteristic comprises elements defining structures having a first range of sizes, and the second similar characteristic comprises elements not defining structures having said first range of sizes.