Decoder and encoder for a digital fingerprint code

1. An identification decoding method for a digital fingerprint code, the method comprising the steps of:

capturing the digital fingerprint code using a digital imaging device;

determining an image captured curve in the captured digital fingerprint code;

determining from a set of two-dimensional points on the image captured curve a set of thicknesses in a direction perpendicular to the image captured curve; and

determining a plurality of N-bit data from the set of thicknesses and a location of the set of two-dimensional points on the image captured curve; wherein

the image captured curve is a bounded, non-intersecting, continuous line;

wherein

the digital fingerprint code is an identification code which includes a set of curves and a content embedded by the plurality of N-bit data;

each possible value of N-bit data in the plurality of N-bit data has a thickness and a length;

the plurality of N-bit data includes a first N-bit data and a different second N-bit data on a curve of the set of curves; and

a thickness (T N,i,1 ) of a value (v N,1 ) of the first N-bit data on the image captured curve is different from a thickness (T N,i,2 ) of a value (v N,2 ) of the second N-bit data, and/or wherein a length (L N,i,1 ) of the value (v N,1 ) of the first N-bit data on the image captured curve is different from a length (L N,i,2 ) of the value (v N,2 ) of the second N-bit data.

2. The method according to claim 1 , wherein the each possible value of the N-bit data in the plurality of N-bit data of the digital fingerprint code includes a color (C N,i ), and a color (C N,i,1 ) of the value (v N,1 ) of the first N-bit data on the curve is different from a color (C N,i,2 ) of the value (v N,2 ) of the second N-bit data; and the method further comprises the steps of:

determining in the set of two-dimensional points a set of colors; and

determining the plurality of N-bit data from the set of thicknesses, a location of the set of two-dimensional points on a path, and the set of colors.

3. The method according to claim 2 , wherein the step of determining the plurality of N-bit data includes smoothing and/or approximating a one-dimensional signal from the set of thicknesses according to a location of the set of two-dimensional points on a path.

4. The method according to claim 2 , further comprising the steps of:

masking the image captured curve in the captured digital fingerprint code; and

detecting another image captured curve in the captured digital fingerprint code.

5. The method according to claim 2 , further comprising the step of tracking and tracing for workpieces.

6. The method according to claim 1 , wherein the step of determining the plurality of N-bit data from the set of thicknesses and the location of the set of two-dimensional points on the image captured curve includes the step of generating a one-dimensional signal based on the determined set of locations and corresponding thicknesses.

7. The method according to claim 2 , wherein the step of determining the plurality of N-bit data from the set of thicknesses and the location of the set of two-dimensional points on the image captured curve includes the step of generating a one-dimensional signal based on the determined set of locations and corresponding thicknesses.

8. The method according claim 1 , wherein the step of determining the image capturing is performed using a digital imaging device included in a mobile device, and the mobile device is a mobile computer or a mobile phone.

9. The method according to claim 1 , further comprising the steps:

analyzing the content embedded by the plurality of N-bit data; and

selecting an action according to a result of the step of analyzing the content embedded by the plurality of N-bit data.

10. The method according to claim 1 , wherein the step of determining the plurality of N-bit data includes smoothing and/or approximating a one-dimensional signal from the set of thicknesses according to the location of the set of two-dimensional points on a path.

11. The method according to claim 1 , further comprising the steps of:

masking the image captured curve in the captured digital fingerprint code; and

detecting another image captured curve in the captured digital fingerprint code.

12. The method according to claim 1 , further comprising the step of tracking and tracing for workpieces.

13. An identification encoding method for a digital fingerprint code, the method comprising the steps of:

determining a document;

determining a curve in the document;

determining for an N-bit data of a plurality of N-bit data a thickness and a length;

determining a first segment on the determined curve with a determined length (L N,i );

changing a thickness of a portion in the first segment in a direction perpendicular to a determined thickness; and

generating from the document with the digital fingerprint code a new document;

wherein

the determined curve in the document is a bounded, non-intersecting, continuous line;

the digital fingerprint code is an identification code which includes a set of curves and a content embedded by the plurality of N-bit data;

each possible value of N-bit data in the plurality of N-bit data has a thickness and a length;

the plurality of N-bit data includes a first N-bit data and a different second N-bit data on a curve of the set of curves; and

a thickness (T N,i,1 ) of a value (v N,1 ) of the first N-bit data on the curve is different from a thickness (T N,i,2 ) of a value (v N,2 ) of the second N-bit data and/or wherein a length (L N,i,1 ) of the value (v N,1 ) of the first N-bit data on the curve is different from a length (L N,i,2 ) of the value (v N,2 ) of the second N-bit data.

14. The method according to claim 13 , further comprising the steps of:

determining a thickness (T N,i ) and a length (L N,i ) of a following N-bit data of the plurality of N-bit data;

determining a second segment on the determined curve, following the first segment, wherein the second segment has the determined length of the following N-bit data; and

changing a thickness of a portion in the second segment to the determined thickness of the following N-bit data.

15. The method according to claim 13 , further comprising the following steps of:

determining for the N-bit data a color (C N,i ); and

changing the color of the segment to the determined color (C N,i ).

16. The method according to claim 13 , wherein the step of determining the curve includes the step of generating a plane filling line pattern.