Method and system for generating a representation of a finger print minutiae information
The invention relates to a method for generating a representation of a finger print minutiae information. The invention also relates to a method for generating a representation of a finger print for biometric template protection purposes Biometric template protection techniques provide technological means to protect the privacy of biometric reference information stored in biometric. systems These methods stand in sharp contrast to approaches where biometric information is protected only by legislation and procedures around storage facilities. These systems are not reliable as they are susceptible to human and procedural errors. Template protection guarantees the protection of biometric information without the assumption that individuals are trusted or procedures are properly implemented.
1. Method for generating a representation of a finger print minutiae information comprising the steps of:
obtaining said minutiae information; obtaining at least one reference point P in said finger print; determining a coordinate system based on said reference point P;
determining sampled function values of said minutiae information in said coordinate system, wherein each sampled function value contains at least the minutiae locations and orientations with respect to said reference point P embedded using a pre-defined set of spatial filters;
generating a vector representation based on said sampled function values.
2. Method according to claim 1 , wherein said coordinate system is characterized by the step of:
defining a circle C R around said reference point P.
3. Method according to claim 1 , wherein said sampled function values are characterized by the steps of:
determining distinct feature sample values by projecting said minutiae information on to said circle CR;
generating a feature vector representation based on said distinct feature sample values.
4. Method according to claim 1 , characterized by the step of using a plurality of said reference points P to generate a plurality of feature vectors.
5. Method according to claim 4 , characterized by the step of combining said plurality of feature vectors into a single feature vector.
6. Method according to claim 5 , wherein said combination of said plurality of feature vectors is a linear combination of the individual vectors.
7. Method according to claim 1 , wherein said reference point P is at least one or a group of
single or multiple core points of the finger print;
single or multiple delta points of the finger print; single or multiple minutiae locations;
a mass center of a finger print image; a mass center of minutiae locations.
8. Method according to claim 1 , wherein said minutiae information comprises at least one or more of
a minutiae direction;
a minutiae type;
a minutiae quality;
location information of said minutiae with respect to said reference point P.
9. Method according to claim 1 , wherein the minutia are grouped into a plurality of distinct sets, and the contribution of said plurality of distinct sets are merged into independent feature vectors or combinations thereof.
10. Method according to claim 9 wherein said clustering is achieved according to their radial distance from the reference stable point.
11. A system for generating a representation of minutiae locations in a finger print comprising;
capturing means for capturing the finger print of a person;
image processing means arranged for
processing said finger print being captured in a finger print image; as well as
determining said minutiae locations in said finger print image;
determining at least one reference point P in said finger print image;
determining ordered minutiae values as functions of minutiae parameters and relative minutiae locations with respect to said reference point, wherein each ordered minutiae value contains at least the minutiae locations and orientations with respect to said reference point P embedded using a pre-defined set of spatial filters; and
generating a vector representation based on said ordered minutiae values.
12. A method for generating a representation of a finger print minutiae information comprising the steps of:
obtaining said minutiae information;
obtaining at least one reference point P in said finger print;
determining a coordinate system based on said reference point P and defining a circle C R around said reference point P;
determining sampled function values of said minutiae information in said coordinate system, wherein each sampled function value contains at least the minutiae locations and orientations with respect to said reference point P embedded using a pre-defined set of spatial filters, the step characterized by determining distinct feature sample function, the step characterized by determining distinct feature sample function values by projecting said minutiae information on to said circle C R ; and
generating a feature vector representation based on the said distinct feature sample values.