Patent attributes
A device includes a storage 52 for storing a reference pattern corresponding to a part of a workpiece outer peripheral part, an imager 27 for imaging the outer peripheral part at least for one turn of a workpiece by such imaging at a fixed point as to include at least a part of the outer peripheral part in an imaging field of view, an image processor 55 for detecting a region corresponding to the reference pattern by performing a pattern matching process, and a misalignment detector 51 for detecting the misalignment based on information on a position of each of a plurality of the detected regions. The reference pattern corresponds in shape to a plurality of characteristic parts that present on the outer peripheral part, have shapes congruent to each other and have a mutually symmetrical positional relationship with respect to rotation about the center axis.
