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 Title: |
US5995640:
System and method for determining if a fingerprint image contains an image portion representing a dry fingerprint impression
[ Derwent Title ]
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| Country: |
US United States of America
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| Inventor: |
Bolle, Rudolf Maarten; Bedford Hills, NY
Pankanti, Sharathchandra Umapatirao; Mt. Kisco, NY
Yao, Yi-Sheng; Scarsdale, NY
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| Assignee: |
International Business Machines Corporation, Armonk, NY
other patents from INTERNATIONAL BUSINESS MACHINES CORPORATION (280070) (approx. 44,393)
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| Published / Filed: |
1999-11-30
/ 1996-10-23
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| Application Number: |
US1996000735721
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| IPC Code: |
Advanced:
G06K 9/00;
Core:
more...
IPC-7:
G06K 9/00;
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| ECLA Code: |
G06K9/00A1; G06K9/00Q;
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| U.S. Class: |
Current:
382/124;
382/125;
382/272;
Original:
382/124;
382/125;
382/272;
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| Field of Search: |
382/124,125,126,116,274,266,263,272
283/068,69,78
356/071
340/825.34
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| Priority Number: |
| 1996-10-23 |
US1996000735721 |
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| Abstract: |
A fingerprint image is divided into blocks of pixels. The blocks are also determined to be within the foreground or background of the image. A dryness process determines a mean intensity of pixels within each foreground block, a second mean intensity of pixels for those pixels whose intensities are smaller than the mean intensity, a standard deviation of intensities of all pixels within the respective foreground block, and a contrast measure being a function of a first ratio of the second mean intensity to the standard deviation. A comparator that determines that the foreground block is a dry block if the contrast measure is larger than a dryness threshold and that the image is a dry image if a second ratio of the number of dry blocks to total number of foreground blocks is larger than a third dryness threshold.
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| Attorney, Agent or Firm: |
Percello, Louis J. ;
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| Primary / Asst. Examiners: |
Kelley, Christopher S; Chawan, Sheela
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| INPADOC Legal Status: |
Show legal status actions
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| Family: |
None
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First Claim:
Show all 18 claims |
We claim:
1. A system for determining whether fingerprint images contain dry impressions comprising:
- a computer comprising at least one central processing unit, at least one memory, and at least one input device;
- at least one fingerprint image having a foreground and a background and being acquired by the input device and stored in the at least one memory, the at least one fingerprint image further comprising a plurality of blocks of pixels;
- a dryness process that operates on said computer for determining a mean intensity of pixels within each foreground block of pixels, for determining a second mean intensity of pixels for those pixels within the respective foreground block of pixels whose intensities are less than the mean intensity, and for determining a standard deviation of intensities of all pixels within the respective foreground block of pixels, wherein a contrast measure is a function of a first ratio of the determined second mean intensity to the determined standard deviation; and
- a comparator that determines that the foreground block of pixels is a dry block if the contrast measure is greater than a dryness threshold, and that further determines that the fingerprint image is a dry image if a second ratio of the number of dry blocks to a total number of foreground blocks is larger than a second dryness threshold.
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| Background / Summary: |
Show background / summary
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| Drawing Descriptions: |
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| Description: |
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| Forward References: |
Show 8 U.S. patent(s) that reference this one
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| Foreign References: |
None
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| Other References: |
N. K. Ratha, S. Chen and A. K. Jain, "Adaptive Flow Orientation-Based Feature Extraction in Fingerprint Images," Pergamon, Pattern Recognition, vol.28, No.11, pp. 1657-1672, 1995.
(16 pages)
Cited by 22 patents
[ISI abstract]
B. M. Mehtre, "Fingerprint Image Analysis for Automatic Identification," R and D Division, CMC Limited, 115 Sarojini Devi Road, Secunderabad-500 003, India, Machine Vision and Application Springer-Verlag 1993.
D. H. Ballard and Christopher M. Brown, "Computer Vision--Region Growing," Department of Computer Science, University of Rochester, Rochester, NY, Prentice-Hall, Inc., Englewood Cliffs, NJ 07632, pp. 149-150, 1982.
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