Method of and device for identification of fingermarks

• US 7,003,141 B1
• Filed: 06/19/2001
• Issued: 02/21/2006
• Est. Priority Date: 06/21/2000
• Status: Expired due to Fees

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Kroeninger, Mario, Lichtermann, Jan
• Primary Examiner(s): Ahmed, Samir
• Assistant Examiner(s): KIM, CHONG R
• Application Number:
  US09/884,838
• Publication Number:
  US 20020015515A1
• Time in Patent Office: 1,708 Days
• Field of Search: 382/115, 382124-127, 382/209, 382/224, 340/5.53, 340/5.83
• US Class Current: 382/124
• CPC Class Codes: G06V 40/1365 Matching; Classification

Abstract

Identification of a fingermark is performed by obtaining for a fingermark a fingermark image, storing reference fingermarks in a databank, comparing the obtained fingermark image with the reference fingermarks for identification, before the identification determining for each reference fingermark in comparison with the obtained fingermark image a similarity degree, sorting the reference fingermarks in the databank in accordance with the similarity degree, and performing the identification of the fingermark beginning with the reference fingermark which leads to the greatest similarity degree.

Claims

1. A method of identification of a fingermark, comprising obtaining for a fingermark a fingermark image;

storing reference fingermarks in a databank;

comparing the obtained fingermark image with the reference fingermarks for identification;

before the identification determining for each reference fingermark in comparison with the obtained fingermark image a similarity degree;

sorting the reference fingermarks in the databank in accordance with the similarity degree; and

performing the identification of the fingermark beginning with the reference fingermark which leads to a greatest similarity degree; and

placing square areas around a reference point of the obtained fingermark;

multiplying the area with window function;

transforming the area by means of a first integral transform in a space frequency region;

determining features in the areas of the reference point;

evaluating for the features the space frequencies in accordance with amount and direction; and

determining by the features of the obtained fingermark and the reference fingermark correspondingly the similarity degree for the corresponding reference fingermark.

2. A method as defined in claim 1;

and further comprising laying the square areas in different sizes.

3. A method as defined in claim 1, and further comprising breaking a power density spectrum of the areas of the reference points in sectors and rings;

summing for the sectors and the ring the powers of the corresponding containing space frequencies so that for the sectors a degree for the orientation is provided and for the rings a degree for the amount;

forming thereby a ring vector and a sector vector;

forming the ring vector and the sector vector as a feature vector; and

comparing with a feature vector of the reference finger marks to determine the similarity degree.

4. A method as defined in claim 3;

and further comprising joining the comparison of the ring vector and the sector vectors before ard after a second integral transform to the similarity degree for the corresponding reference fingermark.

5. A method as defined in claim 4;

and further comprising performing the comparison by a method selected from the group consisting of a difference square method and a correlation method.

6. A method as defined in claim 3;

and further comprising comparing the ring vector with the sector vector before and after each second integral transformation with the corresponding ring vector and the sector vector of the corresponding reference finger mark, to determine the similarity for the corresponding reference fingermark.