Encoding and decoding digital signals in conductive ink structures

• US 10,686,963 B1
• Filed: 05/19/2017
• Issued: 06/16/2020
• Est. Priority Date: 05/20/2016
• Status: Active Grant

• Current Assignee: Digimarc Corporation
• Original Assignee: Digimarc Corporation
• Inventors: Rodriguez, Tony F.
• Primary Examiner(s): Yang, Qian
• Application Number:
  US15/600,676
• Time in Patent Office: 1,124 Days
• CPC Class Codes: G06T 1/0092 Payload characteristic determination in a watermarking scheme, e.g. number of bits to be embedded
• CPC Class Codes: H04N 1/32261 in binary data H04N1/32256 takes precedence
• CPC Class Codes: H04N 1/32309 in colour image data
• CPC Class Codes: H04N 1/32336 Informed embedding, i.e. the original image being known for the encoding or decoding method

Abstract

Digital encoding methods are used to encode digital payloads in image and conductive ink carriers. These carriers are applied to objects by various printing technologies, together in one or more ink formulations or in separate ink layers on an object. The image payload is extracted from an image sensed with image sensor, while the conductive ink payload is extracted from an image sensed with a capacitive or resistive sensor or like device for sensing the modulation in conductivity of the printed conductive ink elements.

Claims

1. An object comprising:

a substrate; and

a pattern of conductive ink elements printed on the substrate;

the pattern of conductive ink elements comprising plural carrier signals, a first carrier signal being modulated to convey a first message symbol, and a second carrier signal being modulated to convey a second message symbol;

each of the plural carrier signals comprising plural conductive ink elements mapped to spatial locations on the substrate;

wherein the pattern of conductive ink elements form a two-dimensional pattern of capacitive ink structures readable by a two dimensional capacitive sensor array;

a layer of ink in which ink has a color property that is modulated to carry an auxiliary machine readable signal and a conductive ink property that is modulated to carry the pattern of conductive ink elements;

wherein the auxiliary machine readable signal comprises a data message that is related to a data message encoded in the pattern of conductive ink elements.

2. The object of claim 1 wherein the conductive ink elements form a binary pattern, wherein presence of a conductive ink element on the substrate conveys a first binary symbol and absence of a conductive ink element on the substrate conveys a second binary symbol.

3. The object of claim 1 wherein amount of conductive ink applied to a spatial location is varied in thickness to form the pattern of conductive ink elements comprising multi-valued conductive ink structures at the spatial locations, the multi-valued conductive ink structures having at least two different values conveying an auxiliary data signal, comprised of multi-valued pixels, where the multi-valued pixels are mapped to spatial locations on the substrate.

4. The object of claim 3 wherein the multi-valued conductive ink elements convey a variable payload message in the auxiliary data signal and a synchronization signal.

5. The object of claim 1 wherein object includes one or more layers of ink, where ink in the one or more layers has a color property that is modulated to carry an auxiliary machine readable signal and a conductive ink property that is modulated to carry the pattern of conductive ink elements.

6. The object of claim 5 wherein the pattern of conductive ink elements forms a first ink layer, and further including a second ink layer carrying the auxiliary machine readable signal in modulation of a color channel.

7. The object of claim 5 wherein the auxiliary machine readable signal comprises a synchronization signal that is oriented relative to the pattern of conductive ink elements to convey information.

8. The object of claim 1 comprising:

a printed ink layer, the printed ink layer comprising a color property that is modulated to carry an auxiliary machine readable signal;

the auxiliary machine readable signal and the pattern being related to each other to convey machine readable information.

9. The object of claim 8 wherein the conductive ink elements form a binary pattern, wherein presence of a conductive ink element on the substrate conveys a first binary symbol and absence of a conductive ink element on the substrate conveys a second binary symbol.

10. The object of claim 8 wherein the conductive ink elements form capacitive ink structures readable by a capacitive sensor array.

11. The object of claim 8 wherein an amount of conductive ink applied to a spatial location is varied in thickness to form the pattern of conductive ink elements comprising multi-valued conductive ink structures at the spatial locations, the multi-valued conductive ink structures having at least two different values conveying an auxiliary data signal, comprised of multi-valued pixels, where the multi-valued pixels are mapped to spatial locations on the substrate.

12. The object of claim 11 wherein the multi-valued conductive ink elements convey a variable payload message in the auxiliary data signal and a synchronization signal.

13. The object of claim 8 wherein the object includes one or more layers of ink, where ink in the one or more layers has a color property that is modulated to carry an auxiliary machine readable signal and a conductive ink property that is modulated to carry the pattern of conductive ink elements.

14. The object of claim 13 wherein the pattern of conductive ink elements forms a first ink layer, and further including a second ink layer carrying the auxiliary machine readable signal in modulation of a color channel.

15. The object of claim 13 wherein the auxiliary machine readable signal comprises a synchronization signal that is oriented relative to the pattern of conductive ink elements to convey information.

16. The object of claim 13 wherein the auxiliary machine readable signal comprises a data message that is related to a data message encoded in the pattern of conductive ink elements.