Numerical model for image feature extraction

1. A method performed by a computer for extracting features from an image, the method comprising:

dividing the image into a plurality of local regions with a surface appearance of fluid flow;

establishing a mathematical model according to conditions of the plurality of local regions with a surface appearance of fluid flow;

solving the mathematical model; and

mapping respective values of the solutions of the mathematical model to respective local regions of the image.

2. The method of claim 1 , wherein the step of establishing a mathematical model comprises:

forming a partial differential equation;

determining initial conditions for the partial differential equation; and

determining boundary condition for the partial differential equation.

3. The method of claim 2 , wherein the step of determining initial conditions comprises:

normalizing the image to reduce variations in gray-level values along ridges of the image;

estimating property values the image; and

mapping the estimated property values into weight coefficients of the partial differential equation.

4. The method of claim 2 , wherein the step of forming a partial differential equation comprises:

calculating a plurality of intrinsic properties of the image according to image ridge pattern; and

mapping the plurality of intrinsic properties into coefficients of the partial differential equation.

5. The method of claim 2 , wherein the step of determining initial conditions comprises:

normalizing the image to reduce variations in gray-level values along ridges of the image;

estimating property values of the image; and

mapping the estimated property values into weight coefficients of the partial differential equation.

6. The method of claim 2 , wherein the step of determining boundary condition comprises:

drawing a close boundary within the image; and

setting boundary condition on the drawn boundary.

7. The method of claim 1 , wherein the image is a fingerprint.

8. The method of claim 1 , wherein the image is a facial image.

9. The method of claim 1 , wherein the image is a hand-palm image.

10. The method of claim 1 , wherein the image is an eye iris image.

11. The method of claim 1 , wherein the image is a texture image.

12. The method of claim 1 , wherein the image is an eye retina image.

13. A method performed by a computer for image processing of a biometric image, the method comprising:

dividing the biometric image into a plurality of local regions each with a flow-like pattern;

calculating an intrinsic property of each of the plurality of the local regions according to flow-like pattern to establish numerical relationship between visual appearance of each of the plurality of local regions; and

approximating solutions of a numerical model according to the established numerical relationship to determine features of the biometric image.

14. The method of claim 13 , wherein the step of calculating an intrinsic property comprises:

forming a partial differential equation;

mapping the plurality of intrinsic properties into coefficients of the partial differential equation; and

determining a boundary condition for the partial differential equation from the image to establish a relationship between properties of the image and the partial differential equation.

15. The method of claim 14 , wherein the step of forming a partial differential equation comprises:

determining initial conditions for the partial differential equation; and

determining boundary condition for the partial differential equation.

16. The method of claim 14 , wherein the step of determining initial conditions comprises:

normalizing the image to reduce variations in gray-level values along ridges of the image;

estimating property values the image; and

mapping the estimated property values into weight coefficients of the partial differential equation.

17. The method of claim 14 , wherein the step of determining boundary condition comprises:

drawing a close boundary within the image; and

setting boundary condition on the drawn boundary.

18. The method of claim 13 , wherein the biometric image is one or more of a fingerprint image, a facial image, a hand-palm image, an eye iris image, a texture image, and an eye retina image.

19. A digital signal processor (DSP) having stored thereon a set of instructions including instruction for extracting features from an image and when executed by the DSP causing the DSP to perform the steps of:

establishing a mathematical model according to conditions of the plurality of local regions with a surface appearance of fluid flow;

solving the mathematical model; and

mapping respective values of the solutions of the mathematical model to respective local regions of the image.

20. The DSP of claim 19 , wherein the image is one or more of a fingerprint image, a facial image, a hand-palm image, an eye iris image, a texture image, and an eye retina image.