Methods for matching ridge orientation characteristic maps and associated finger biometric sensor

A method for comparing a finger biometric verify ridge orientation characteristic map to a finger biometric enrollment ridge orientation characteristic map performed by a finger biometric controller comprising:

• sensing finger biometric data from a finger using a finger biometric sensor;
• generating the finger biometric verify ridge orientation characteristic map based upon the finger biometric data;
• generating a first probability distribution function substantially for corresponding values of the verify and enrollment ridge orientation characteristic maps that differ from one another by less than or equal to a threshold difference;
• generating a second probability distribution function substantially for corresponding values of the verify and enrollment ridge orientation characteristic maps that differ from one another by more than the threshold difference;
• and
• comparing the verify ridge orientation characteristic map to the enrollment ridge orientation characteristic map to determine a match therewith based upon the first and second probability distribution functions.

A finger biometric sensor comprising:

• a finger biometric sensing area for sensing finger biometric enrollment data from a finger;
• and
• a processor connected to said finger biometric sensing area for
• arranging the finger biometric data into an array of cells,
• estimating at least one respective gradient for each cell,
• generating an initial ridge orientation characteristic map for the finger based upon the finger biometric data based upon the gradients by at least
• tessellating the finger biometric data into an array of cells,
• estimating at least one respective gradient for each cell, and
• generating the initial ridge orientation characteristic map based upon the estimated gradients;
• estimating an amount of noise in the initial ridge orientation characteristic map,
• adaptively filtering the gradients based upon the amount of estimated noise, and
• generating a final ridge orientation characteristic map based upon the filtered gradients.