Method and system for detecting a defect in projected portions of an object having the projected portions formed in the same shape with a predetermined pitch along an arc

A system for detecting a defect on an object having projected portions formed in the same shape along an arc with a predetermined pitch, comprising

• imaging means for imaging an object to be inspected,
• image capture means for holding an picked-up image as digital data,
• region area detection means for analyzing the digital data held by said image capture means to determine an arc circumscribing a tip of each of the projected portion of said object, and then extracting each overlapping region formed by an overlapping portion between an inner portion of a region defined by said arc and a cut-away portion of said object to determine an area of each overlapping region,
• region area comparison means for comparing the area of each overlapping region determined by said region area detection means with each other to determine an area difference, and
• defect determination means for determining that no defect exists on said object if the area difference determined by said region area comparison means falls within a range of predetermined criteria, whereas determining that a defect exists on said object if said area difference exceeds the range of the predetermined criteria.

A method for detecting a defect on an object having projected portions formed in the same shape along an arc with a predetermined pitch, comprising the steps of:

• determining an arc inscribing a tip of each projected portion of an object to be inspected,
• extracting each overlapping region formed by an overlapping portion between an outer portion of a region defined by said arc and a cut-away portion of said object to determine an area of each overlapping region,
• comparing the area of each of said overlapping regions with each other, and
• determining that no defect exists on said object if each area difference falls within a range of predetermined criteria, whereas determining that a defect exists on said object if said area difference exceeds the range of the predetermined criteria.

A system for detecting a defect on an object having projected portions formed in the same shape along an arc with a predetermined pitch, comprising

• imaging means for imaging an object to be inspected,
• image capture means for holding an picked-up image as digital data,
• region area detection means for analyzing the digital data held by said image capture means to determine an arc inscribing a tip of each of the projected portion of said object, and then extracting each overlapping region formed by an overlapping portion between an outer portion of a region defined by said arc and a cut-away portion of said object to determine an area of each overlapping region,
• region area comparison means for comparing the area of each overlapping region determined by said region area detection means with each other to determine an area difference, and
• defect determination means for determining that no defect exists on said object if the area difference determined by said region area comparison means falls within a range of predetermined criteria, whereas determining that a defect exists on said object if said area difference exceeds the range of the predetermined criteria.