Pre-processing system for pre-processing an image signal succession prior to identification

• US 4,827,527 A
• Filed: 08/29/1985
• Issued: 05/02/1989
• Est. Priority Date: 08/30/1984
• Status: Expired due to Fees

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Morita, Koichiro, Asai, Ko
• Primary Examiner(s): Boudreau, Leo H.
• Assistant Examiner(s): Mancuso, Joseph
• Application Number:
  US06/770,510
• Time in Patent Office: 1,342 Days
• Field of Search: 382/4, 382/5, 382/44, 382/45, 382/46, 382/56, 382/48, 356/71
• US Class Current: 382/127
• CPC Class Codes: G06V 40/1347 Preprocessing; Feature extraction
• CPC Class Codes: G07C 9/37 using biometric data, e.g. fingerprints, iris scans or voice recognition

Abstract

In a pre-processing system (45) for pre-processing a succession of image signals which are extracted from an object on an input surface and which are representative of a ridge pattern of the object, a center position of the ridge pattern is determined with reference to the image signal succession and is compared with a center zone of the input surface so as to decide whether or not the center position is placed at the center zone. The center position can be decided by monitoring occurrence of runs along each scanning line and by detecting a maximum one of the numbers of runs. Alternatively, the center position may be decided by monitoring ridges extended in a preselected direction with respect to the scanning lines and by detecting a maximum one of the numbers of the ridges extended in the preselected direction. The pre-processing system may detect whether the object is true or false by monitoring the image signal succession.

Claims

1. A pre-processing system for use in pre-processing a succession of image signals representative of a ridge pattern prior to identification of said ridge pattern, each of said image signals having a grey level classifiable into either level, said image signal succession being divisible into a plurality of partial sequences appearing within a plurality of predetermined durations, respectively, said ridge pattern being derived from an object placed on an input surface, said ridge pattern having a center pattern while said input surface has a center zone, comprising:

run detecting means responsive to said image singal succession for detecting a succession of runs to successively count numbers of the runs for respective predetermined durations, each of said runs being specified by preselected one of said first and said second levels;

comparing means coupled to said run detecting means for comparing the numbers of runs with one another to detect a maximum one of said numbers;

means for determining a position of said center pattern from said maximum one of the numbers to produce a position signal indicative of said position; and

pattern detecting means responsive to said position signal for detecting whether said center pattern is placed at said center zone of the input surface to produce a detection signal representative or whether said identification is to be carried out.

2. A pre-processing system as claimed in Claim 1, wherein said pattern detecting means comprises:

means for indicating a reference position indicative of said center zone; and

means for comparing the position of said center position with said reference position to produce said detection signal.

3. A pre-processing system for use in pre-processing a succession of image signals representative of a ridge pattern composed of ridges prior to identification of said ridge pattern, each of said image signals being derived from an object placed on an input surface by successively scanning said ridge pattern in a single scanning direction, said ridge pattern having a center pattern while said input surface has a center zone, said ridge pattern having a plurality of ridges, comprising:

monitoring means responsive to said image signal succession for monitoring a part of said ridge pattern to produce a sequence of ridge signals representative of said part of the ridge pattern;

direction detecting means coupled to said monitoring means for detecting directions of the ridges from said ridge signal sequence;

angle detecting means coupled to said direction detecting means for detecting angles of the ridges relative to said scanning direction from said directions of the ridges;

counting means coupled to said angle detecting means for counting numbers of the ridges which are perpendicular to said scanning direction; and

determining means coupled to said counting means for determining a position of said center pattern from said numbers of the ridges perpendicular to said scanning direction to produce a position signal representative of said position of the center pattern.

4. A pre-processing system as claimed in claim 3, wherein said position of the center pattern is determined by a maximum one of the numbers of the ridges perpendicular to said scanning direction.