Fingerprint identification method and apparatus

• US 20030123715A1
• Filed: 01/24/2003
• Published: 07/03/2003
• Est. Priority Date: 07/28/2000
• Status: Active Grant

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Uchida, Kaoru
• Granted Patent: US 7,194,115 B2
• Time in Patent Office: Days
• US Class Current: 382/124
• CPC Class Codes: G06V 40/1335 Combining adjacent partial images (e.g. slices) to create a composite input or reference pattern; Tracking a sweeping finger movement

Abstract

A method and device for fingerprint identification implementing precise identification at a high speed by using partial images of a fingerprint obtained through relative movements of a finger to a small sized sensor are provided.

For reassembling a sequence of partial images inputted from a frame input section 50 into a complete image, each of the partial images is collated with a user'"'"'s fingerprint image (template image) registered in a template image storage section 52 to determine a position where the partial image matches best at an optimal position calculator 55, and then combined with a partial composite image stored in a partial composite image storage section 53 at an image combining section 60. When the complete composite image is obtained after repeating the above operations, specific features are extracted from the composite image at a reference character extracting section 62, and collated with those of the template image stored in a template reference character storage section 54. Consequently, user authentication can be performed at a high speed while ensuring stability in the collating operation.

Claims

1. (amended) A fingerprint identification method, in which a sequence of partial images of a fingerprint is inputted and the similarity between the inputted fingerprint and a previously registered one is judged, comprising the steps of:

deciding a position for each of the partial images by using image information of the registered fingerprint;

accumulating first penalty indices, each of which is a minimum value at a position bearing the closest resemblance to each of the partial images in the registered fingerprint image; and

determining that the inputted fingerprint differs from the registered one when the cumulative sum exceeds a predetermined penalty threshold.

2. (amended) A fingerprint identification method, in which a sequence of partial images of a fingerprint is inputted and the similarity between the inputted fingerprint and a previously registered one is judged, comprising the steps of:

deciding a position for each of the partial images by using image information of the registered fingerprint;

calculating a first penalty index of each partial image, which is a minimum value at a position bearing the closest resemblance to each of the partial images in the registered fingerprint image,

arranging and combining the partial images based on the information about the position bearing the closest resemblance to each of the partial images to obtain a composite image;

collating the composite image with the registered fingerprint image;

accumulating the first penalty indices; and

determining that the inputted fingerprint differs from the registered one when the cumulative sum exceeds a predetermined penalty threshold.

3. (amended) A fingerprint identification method, in which a sequence of partial images of a fingerprint is inputted and the similarity between the inputted fingerprint and a previously registered one is judged, comprising the steps of:

deciding a position for each of the partial images by using image information of the registered fingerprint;

accumulating first penalty indices, each of which is a minimum value at a position bearing the closest resemblance to each of the partial images in the registered fingerprint image; and

determining that the inputted fingerprint resembles to the registered one when the cumulative sum of the first penalty indices does not exceed a predetermined penalty threshold, and the area of a partial composite image becomes larger than a predetermined area threshold.

4. (amended) A fingerprint identification method, in which a sequence of partial images of a fingerprint is inputted and the similarity between the inputted fingerprint and a previously registered one is judged, comprising the steps of:

deciding a position for each of the partial images by using image information of the registered fingerprint;

calculating a first penalty index of each partial image, which is a minimum value at a position bearing the closest resemblance to each of the partial images in the registered fingerprint image;

arranging and combining the partial images based on the information about the position bearing the closest resemblance to each of the partial images to obtain a composite image;

collating the composite image with the registered fingerprint image;

accumulating the first penalty indices; and

determining that the inputted fingerprint resembles to the registered one when the cumulative sum of the first penalty indices does not exceed a predetermined penalty threshold, and the area of the partial composite image becomes larger than a predetermined area threshold.

5. (amended) A fingerprint identification method, in which a sequence of partial images of a fingerprint is inputted and the similarity between the inputted fingerprint and a previously registered one is judged, comprising the steps of:

deciding a position for each of the partial images by using image information of the registered fingerprint;

calculating a first penalty index of each partial image, which is a minimum value at a position bearing the closest resemblance to each of the partial images in the registered fingerprint image;

arranging and combining the partial images based on the information about the position bearing the closest resemblance to each of the partial images to obtain a composite image;

collating the composite image with the registered fingerprint image;

finding a position where the partial image fits with least discordance in the partial composite image while finding the position bearing the closest resemblance to each partial image in the registered fingerprint image; and

arranging and combining the partial images based on the~results.

6. (amended) The fingerprint identification method claimed in claim 5, further comprising the steps of:

calculating a second penalty index of each partial image, which is a minimum value at a position where the partial image fits with least discordance in the partial composite image as well as the first penalty index; and

integrating calculation results of the first and second penalty indices according to the weighted average of the penalty indices to determine the position.

7. (amended) The fingerprint identification method claimed in claim 5, further comprising the steps of:

integrating calculation results of the first and second penalty indices according to a weighted average method, in which the second penalty index adds weight as the partial images are added to the partial composite image; and

determining the position based on the integration result.

8. (amended) A fingerprint identification device for judging the similarity between an inputted fingerprint and a previously registered one by using a sequence of partial images of the fingerprint, comprising:

a frame image input means for inputting the partial images of the fingerprint;

a registered image optimum position calculating means for calculating first penalty indices, each of which is a minimum value at a position bearing the closest resemblance to each of the partial images in the registered fingerprint image;

an image combining means for combining the partial image arranged at the position bearing the closest resemblance with a partial composite image having been composed up to this point to produce an extended partial composite image;

a fingerprint collating means for judging the similarity between a composite image composed of all the inputted partial images and the registered fingerprint image; and

a composite image optimum position calculating means for finding a position where the partial image fits with least discordance in the partial composite image composed of previous partial images;

wherein

the image combining means combines the partial images according to the results derived by the registered image optimum position calculating means and the composite image optimum position calculating means.

9. (amended) A fingerprint identification device for judging the similarity between an inputted fingerprint and a previously registered one by using a sequence of partial images of the fingerprint, comprising:

a frame image input means for inputting the partial images of the fingerprint;

a registered image optimum position calculating means for calculating first penalty indices, each of which is a minimum value at a position bearing the closest resemblance to each of the partial images in the registered fingerprint image;

an image combining means for combining the partial image arranged at the position bearing the closest resemblance with a partial composite image having been composed up to this point to produce an extended partial composite image;

a fingerprint collating means for judging the similarity between a composite image composed of all the inputted partial images and the registered fingerprint image; and

a mismatch determination means for accumulating the first penalty indices and determining that the inputted fingerprint differs from the registered one when the cumulative sum exceeds a predetermined penalty threshold.

10. (amended) A fingerprint identification device for judging the similarity between an inputted fingerprint and a previously registered one by using a sequence of partial images of the fingerprint, comprising:

a frame image input means for inputting the partial images of the fingerprint;

a registered image optimum position calculating means for calculating first penalty indices, each of which is a minimum value at a position bearing the closest resemblance to each of the partial images in the registered fingerprint image;

an image combining means for combining the partial image arranged at the position bearing the closest resemblance with a partial composite image having been composed up to this point to produce an extended partial composite image;

a fingerprint collating means for judging the similarity between a composite image composed of all the inputted partial images and the registered fingerprint image;

a composite image optimum position calculating means for finding a position where the partial image fits with least discordance in the partial composite image composed of previous partial images; and

a mismatch determination means for accumulating the first penalty indices and determining that the inputted fingerprint differs from the registered one when the cumulative sum exceeds a predetermined penalty threshold.

11. (amended) A fingerprint identification device for judging the similarity between an inputted fingerprint and a previously registered one by using a sequence of partial images of the fingerprint, comprising:

a frame image input means for inputting the partial images of the fingerprint;

a registered image optimum position calculating means for calculating first penalty indices, each of which is a minimum value at a position bearing the closest resemblance to each of the partial images in the registered fingerprint image;

an image combining means for combining the partial image arranged at the position bearing the closest resemblance with a partial composite image having been composed up to this point to produce an extended partial composite image;

a fingerprint collating means for judging the similarity between a composite image composed of all the inputted partial images and the registered fingerprint image; and

a rough match determination means for accumulating the first penalty indices, and determining that the inputted fingerprint matches the registered one when the cumulative sum does not exceed a predetermined penalty threshold, and the area of the partial composite image combined by the image combining means becomes larger than a predetermined area threshold.

12. (added) A fingerprint identification device for judging the similarity between an inputted fingerprint and a previously registered one by using a sequence of partial images of the fingerprint, comprising:

a frame image input means for inputting the partial images of the fingerprint;

a registered image optimum position calculating means for calculating first penalty indices, each of which is a minimum value at a position bearing the closest resemblance to each of the partial images in the registered fingerprint image;

an image combining means for combining the partial image arranged at the position bearing the closest resemblance with a partial composite image having been composed up to this point to produce an extended partial composite image;

a fingerprint collating means for judging the similarity between a composite image composed of all the inputted partial images and the registered fingerprint image;

a composite image optimum position calculating means for finding a position where the partial image fits with least discordance in the partial composite image composed of previous partial images; and

a rough match determination means for accumulating the first penalty indices, and determining that the inputted fingerprint matches the registered one when the cumulative sum does not exceed a predetermined penalty threshold, and the area of the partial composite image combined by the image combining means becomes larger than a predetermined area threshold;

wherein

the image combining means combines the partial images according to the results derived by the registered image optimum position calculating means and the composite image optimum position calculating means.