Disk-shaped dial inspection method, inspection apparatus, and recording medium

The invention discloses an inspection method of a disc-shaped dial, an inspection apparatus, and a recording medium. The inspection method comprises: an image data acquisition step for acquiring data related to an image of a disc-shaped dial as disc-shaped dial image data; and a polar coordinate conversion step for converting the disc-shaped dial image data into polar coordinates using the center of the disc-shaped dial as a reference to generate polar coordinate scale image data. The defect detection step comprises: a processing area setting step for setting a processing area for each scale line on a polar coordinate angle display axis; a center-of-gravity calculation step for calculating the center of gravity for each processing area; and a center-of-gravity distance calculation step for calculating the center-of-gravity distance calculated in the center-of-gravity calculation step. Defect detection is performed by comparing a pitch of scales in the polar coordinate scale image data with a predetermined ref