公开(公告)号：DE1946861A1

公开(公告)日：1970-04-02

申请号：DE1946861

申请日：1969-09-16

Applicant: IBM

Inventor： MANTON BERGER JAY ,  JACK LEVINE WILBUR ,  MALEK KASEM

IPC: G06K9/00 ,  G06K9/16

Abstract: 1,232,329. Fingerprint recognition. INTERNATIONAL BUSINESS MACHINES CORP. 27 Aug., 1969 [25 Sept., 1968], No. 42565/69. Heading G4R. Pattern recognition apparatus, for identifying a core of a fingerprint having a plurality of ridges, line scans the fingerprint at first and second angles to produce co-ordinates of first and second respective sets of points of tangency of the scanning lines with the ridges, and compares respective co-ordinates of the points of the two sets to determine the pair of points having co-ordinates differing by less than a predetermined quantity, the determined pair of points being taken as the location where the scans converge. The core is scanned in a plurality of parallel lines at the first angle, the distance between the scan lines being approximately the typical ridge thickness. The contents of X and Y counters, driven in step with the scanner, are gated to registers on detection of each white-toblack and following black-to-white transition to give the X and Y co-ordinates of the transitions. The extent of ridge crossing is obtained from the differences of the X and Y co-ordinates of each such pair of corresponding transitions and if it exceeds about twice the ridge thickness, the averages of the X and Y co-ordinates are stored as the co-ordinates of the point of tangency. After the whole core has been scanned at the first angle, scans are performed at the second angle until a point of tangency is obtained and stored in a similar way which is less than the typical distances between adjacent ridges from a point of tangency obtained in the scans at the first angle. The position thus obtained is taken as the core centre used as a reference point from which numbers of ridges can be counted and relative directions of line endings and bifurcations can be determined for storage and comparison for recognition purposes.