Encoded signal systems and methods to ensure minimal robustness

• US 10,506,128 B1
• Filed: 06/18/2018
• Issued: 12/10/2019
• Est. Priority Date: 06/16/2017
• Status: Active Grant

• Current Assignee: Digimarc Corporation
• Original Assignee: Digimarc Corporation
• Inventors: Chadwick, Dean H., Brundage, Trent J.
• Primary Examiner(s): Williams, Miya J
• Application Number:
  US16/011,092
• Time in Patent Office: 540 Days
• Field of Search: None
• CPC Class Codes: G06T 1/0028 Adaptive watermarking, e.g. Human Visual System [HVS]-based watermarking
• CPC Class Codes: G06T 1/005 Robust watermarking, e.g. average attack or collusion attack resistant
• CPC Class Codes: G06T 2201/0202 whereby the quality of watermarked images is measured; Measuring quality or performance of watermarking methods; Balancing between quality and robustness
• CPC Class Codes: G06T 3/40 Scaling of whole images or parts thereof, e.g. expanding or contracting
• CPC Class Codes: G06T 7/90 Determination of colour characteristics
• CPC Class Codes: G06T 9/00 Image coding bandwidth or redundancy reduction for static pictures H04N1/41; coding or decoding of static colour picture signals H04N1/64; methods or arrangements for coding, decoding, compressing or decompressing digital video signals H04N19/00
• CPC Class Codes: H04N 1/32149 Methods relating to embedding, encoding, decoding, detection or retrieval operations
• CPC Class Codes: H04N 1/32309 in colour image data
• CPC Class Codes: H04N 1/3232 Robust embedding or watermarking
• CPC Class Codes: H04N 19/467 characterised by the embedded information being invisible, e.g. watermarking

Abstract

This disclosure relates to advanced signal processing technology including signal encoding and image processing. One implementation describes an encoding system including a masking module. The masking module scales or eliminates signal encoding adjustments based on an image'"'"'s luminance or chrominance values. Of course, other implementations, combinations and claims are also provided.

Claims

1. A system comprising:

an input to receive a design file, the design file comprising an image including an area of layered colors, the image comprising luminance or chrominance values;

one or more multi-core processors and a memory storing instructions that, when the instructions are executed by the one or more multi-core processors, cause the one or more multi-core processors to function as;

a blend module for operating on the design file, the blend module generating reflectance spectra estimates for the image including the area of layered colors, the reflectance spectra estimates provided on a per pixel basis for the design file;

a signal detector to determine whether the design file includes a signal encoded therein;

a signal encoder for encoding a signal in the image to yield an encoded image, in which the signal encoder encodes the image only when the signal detector finds no signal encoded within the design file, the signal encoder transforming the image by introducing positive or negative adjustments in units of the image, with each unit representing a plurality of pixels;

a visibility module for generating visibility information associated with the encoded image, and for reducing visibility of the encoded signal in at least one area of the image;

a mask module for evaluating the image on a unit level to determine whether the luminance or chrominance values, prior to encoding, falls within a predetermined luminance or chrominance range, and for compressing or eliminating the positive or negative adjustments when the luminance or chrominance values fall within the predetermined luminance or chrominance range, the mask module producing a masked, encoded image.

2. The system of claim 1 in which the signal encoder comprises a digital watermark encoder.

3. The system of claim 1 in which the input comprises memory or a communications bus connecting the signal encoder with one or more modules of the system.

4. The system of claim 1 in which the signal detector operates in three stages, in which two of the stages comprise i) a blend module for operating on the image, the blend module generating reflectance spectra estimates for the image including the area of layered colors, the reflectance spectra estimates provided on a per pixel basis for the image, and ii) a payload detection module for decoding one or more payloads from the any encoded signals.

5. The system of claim 4 in which a third stage (iii) comprises a payload aggregation module for aggregating payloads decoded from the any encoded signal.

6. The system of claim 1 in which the mask module operates by:

i) determining whether luminance of a pixel value in a unit of the image prior to encoding (“

LU”

) comprises LU<

=A, where A comprises a first predetermined luminance percentage value, and if true then a scaling factor, F, is not applied to a pixel value;

ii) determining whether LU>

A for remaining n pixels within the unit, where n is a pixel number, and then if true, applying a scaling factor, F, to a positive or negative adjustment according to;

fn=max (0, (C−

LU)/(C−

A)), where the max function returns the maximum of the two values, 0 or (C−

LU)/(C−

A), for each of the n pixels satisfying LU>

A, where fn comprises a pixel scaling factor for a particular pixel, pixel 1 to n, and C comprises a second predetermined luminance percentage value that is greater than the first predetermined pixel vlaue A;

F=min (f1, fn), where the min function returns the minimum f pixel scaling value for all pixels evaluated in the unit from pixel number 1 to n.

7. The system of claim 1 in which the mask module operates by:

scaling positive or negative adjustments on a per unit basis when luminance values associated with the image prior to encoding fall within a first luminance value range;

eliminating positive or negative adjustments on a per unit basis when luminance values associated with the image prior to encoding fall with a second luminance value range, the second luminance value range comprising luminance values above the first luminance value range up to 100% luminance.

8. The system of claim 1, in which the masking module alters positive or negative adjustments depending on value ranges of the image prior to receiving encoding, the value ranges comprising:

Range i;

between 0% luminance to a first predetermined luminance percentage, A %;

Range ii;

between A % to a second predetermined luminance percentage, C %; and

Range iii;

between C % to 100% luminance;

in which

the positive or negative adjustments are not altered when luminance of the image prior to encoding (LU) falls within Range i, the positive or negative adjustments are reduced by a scaling factor when luminance of the image prior to encoding (LU) falls within Range ii, and the positive or negative adjustments are eliminated when luminance of the image prior to encoding (LU) falls within Range iii.

9. An image processing method comprising:

receiving a design file, the design file comprising an image including an area of layered colors, the image comprising luminance or chrominance values;

generating reflectance spectra estimates for the image including the area of layered colors, the reflectance spectra estimates provided on a per pixel basis for the design file;

detecting whether the design file includes a signal encoded therein;

transforming the image by encoding a signal therein to yield an encoded image, in which said transforming encodes the image only when no signal is encoded within the design file, said transforming transforms the image by introducing positive or negative adjustments in units of the image, with each unit representing a plurality of pixels;

generating visibility information associated with the encoded image, and reducing visibility of the encoded signal in at least one area of the encoded image;

evaluating the image on a unit level to determine whether corresponding luminance or chrominance values, prior to encoding, fall within a predetermined luminance or chrominance range, and compressing or eliminating the positive or negative adjustments when the luminance or chrominance values fall within the predetermined luminance or chrominance range.

10. The image processing method of claim 9 in which said transforming utilizes a digital watermark encoder.

11. The image processing method of claim 9 in which the detecting comprises three stages, in which two of the stages comprise i) generating reflectance spectra estimates for the image including the area of layered colors, the reflectance spectra estimates provided on a per pixel basis for the image, and ii) decoding one or more payloads from the any encoded signals.

12. The image processing method of claim 11 in which a third stage (iii) comprises aggregating payloads decoded from the any encoded signals.

13. The image processing method of claim 9 in which the evaluating comprises:

i) determining whether luminance of a pixel value in a unit of the image prior to encoding (“

LU”

) comprises LU<

=A, where A comprises a first predetermined luminance percentage value, and, if true, not apply a scaling factor, F, a corresponding pixel value;

ii) determining whether LU>

A for remaining n pixels within the unit, where n is a number of remaining pixels, and then if true, applying a scaling factor, F, to a positive or negative adjustment according to;

fn=max (0, (C−

LU)/(C−

A)), where the max function returns the maximum of the two values, 0 or (C−

LU)/(C−

A), for each of the n pixels satisfying LU>

A, where fn comprises a pixel scaling factor for a particular pixel, pixel 1 to n, and C comprises a second predetermined luminance percentage value that is greater than the first predetermined pixel value A;

where

F=min (f1, fn), where the min function returns the minimum f pixel scaling value for all pixels evaluated in the unit from pixel number 1 to n.

14. The image processing method of claim 9 in which said evaluating comprises:

scaling positive or negative adjustments on a per unit basis when luminance values associated with the image prior to encoding fall within a first luminance value range;

eliminating positive or negative adjustments on a per unit basis when luminance values associated with the image prior to encoding fall within a second luminance value range, the second luminance value range comprising luminance values above the first luminance value range, and ending at 100% luminance.

15. The image processing method of claim 9, in which said evaluating alters positive or negative adjustments depending on value ranges of the image prior to receiving encoding, the value ranges comprising:

Range i;

between 0% luminance to a first predetermined luminance percentage, A %;

Range ii;

between A % to a second predetermined luminance percentage, C %; and

Range iii;

between C % to 100% luminance;

in which

the positive or negative adjustments are not altered when luminance of the image prior to encoding (LU) falls within Range i, the positive or negative adjustments are reduced by a scaling factor when luminance of the image prior to encoding (LU) falls within Range ii, and the positive or negative adjustments are eliminated when luminance of the image prior to encoding (LU) falls within Range iii.

16. A non-transitory computer readable medium comprising instructions stored thereon, which when executed by one or more multi-core processors, cause the one or more multi-core processors to perform the method of claim 9.

17. A non-transitory computer readable medium comprising instructions stored thereon, which when executed by one or more multi-core processors, cause the one or more multi-core processors to perform the method of claim 13.

18. A non-transitory computer readable medium comprising instructions stored thereon, which when executed by one or more multi-core processors, cause the one or more multi-core processors to perform the method of claim 14.

19. A non-transitory computer readable medium comprising instructions stored thereon, which when executed by one or more multi-core processors, cause the one or more multi-core processors to perform the method of claim 15.