FLAW TYPE CLASSIFICATION BOUNDARY SETTING METHOD IN SURFACE DEFECT DETECTION, AND DEFECT DETECTION METHOD

• Main Authors: NAKAMOTO SHIGEMI, KAZAMA AKIRA, MATSUFUJI YASUHIRO
• Format: Patent
• Language: English
• Published: 08.04.2004
• Edition: 7
• Subjects: AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKINGWITHOUT ESSENTIALLY REMOVING MATERIAL; CALCULATING; COMPUTING; COUNTING; IMAGE DATA PROCESSING OR GENERATION, IN GENERAL; INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIRCHEMICAL OR PHYSICAL PROPERTIES; MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES,OTHERWISE THAN BY ROLLING; MEASURING; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS; MEASURING LENGTH, THICKNESS OR SIMILAR LINEARDIMENSIONS; MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVINGMATERIAL; PERFORMING OPERATIONS; PHYSICS; PUNCHING METAL; TESTING; TRANSPORTING

PROBLEM TO BE SOLVED: To provide a flaw type classification boundary setting method in surface defect detection allowing even an operator without having a special technique to simply realize complicated defect classification, and enabling evaluation capable of remarkably reducing work and of rapidly responding to change of an operation state. SOLUTION: Feature data are inputted for every flaw type (steps S11-S14); parameters (the average vector, a covariance matrix and a coupling coefficient) of a mixture density distribution for every flaw type are found (step S15); an identification boundary for every flaw is determined by using Bayes' theorem based on the found mixture density distribution for every flaw type (step S16); and the likelihood of the determination is calculated (step S17). COPYRIGHT: (C)2004,JPO