04156230 is referenced by 46 patents and cites 5 patents.

A method and apparatus for the smoothing and singularity detection of the ridge contour data of a fingerprint image for classification in an automatic fingerprint identification system. A template scanning window is passed electronically over a digital matrix of ridge contour data to generate a set of correlation values corresponding to each contour data element and to a plurality of reference angle vectors. The correlation values are processed for determination of peaks and valleys. Tests are conducted to determine whether the relative values of peaks and valleys and the relative spacing between peaks and valleys satisfy certain threshold criteria for reliable extraction of fingerprint singularity points for classification. The resultant data, representing the number of correlation peaks and the direction of each, defines the location and angular orientation of cores and deltas of a fingerprint.

Title
Method and apparatus for automatic extraction of fingerprint cores and tri-radii
Application Number
5/847987
Publication Number
4156230
Application Date
November 2, 1977
Publication Date
May 22, 1979
Inventor
Alexander Csiszer
Orange
CA, US
Norman L Bolton
Riverside
CA, US
Gerald D Brown
Mission Viejo
CA, US
Richard D Capello
Orange
CA, US
John P Riganati
Yorba Linda
CA, US
Agent
Rolf M Pitts
H Fredrick Hamann
L Lee Humphries
Assignee
Rockwell International Corporation
CA, US
IPC
G06K 9/00
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