Patent ID: 7260246

Claim:
A pattern-center determination apparatus for determining a pattern center of a fingerprint-like pattern, which is formed with a number of pattern curves, said apparatus comprising: an auxiliary-line generation section for generating a number of successive line segments from an outer circumference side of the pattern curves of the fingerprint-like pattern toward an inner circumference side of the pattern curves in such a manner that each of the line segments intersects each a respective one of the pattern curves perpendicularly or substantially perpendicularly two or more auxiliary lines, thereby generating two or more auxiliary lines each of which consists of the successive line segments; and a pattern-center determination section for determining the pattern center based on one or more intersecting points at which the two or more auxiliary lines generated by said auxiliary-line generation section intersect with each other; wherein said auxiliary-line generation section includes: a start-point setting section for setting an arbitrary point of the fingerprint-like pattern as a start point; a reference-circle generation section for generating a reference circle of a predetermined radius centered at the start point set by said start-point setting section; a reference-circle-intersecting-point calculation section for calculating intersecting points of the reference circle generated by said reference-circle generation section and the pattern curves of the fingerprint-like pattern; an intersecting-point extraction section for extracting those two of the intersecting points calculated by said reference-circle-intersecting-point calculation section which satisfy a predetermined condition; an end-point calculation section for calculating a middle point of the two intersecting points extracted by said intersecting-point extraction section as an end point; and a line-segment generation section for generating a line segment interconnecting the start point set by said start-point setting section and the end point calculated by said end-point calculation section; wherein said start-point setting section is operable to set the end point as a new start point so that said reference-circle generation section, said reference-circle-intersecting-point calculation section, said intersecting-point extraction section, said end-point calculation section and said line-segment generation section repeatedly generate a new line segment, thereby generating the auxiliary line as a number of successive line segments.