Stud welding ferrule and apparatus

A system for automatically identifying one or more welding site locations on a surface of a target metal marked with a plurality of welding site candidates, the system comprising:

• an imager configured to acquire an image of the surface of the target metal including the plurality of welding site candidates, wherein the acquired image comprises a plurality of pixels with each pixel having a corresponding intensity value;
• and
• a processing circuit configured to:
• receive the acquired image,
• compare each intensity value to an intensity threshold for pixel clustering,
• identify a plurality of pixel clusters, each pixel cluster corresponding to a different one of the plurality of welding site candidates, wherein each pixel cluster is a cluster of contiguous pixels that have intensity values that are equal to or greater than the intensity threshold,
• for each pixel cluster, determine whether a total pixel area making up the pixel cluster is less than a threshold pixel area,
• remove any pixel cluster from consideration as a welding site location if the total pixel area of the pixel cluster is less than the threshold pixel area,
• identify first remaining pixel clusters comprising at least one pixel cluster whose total pixel area is equal to or greater than the threshold pixel area,
• for each pixel cluster of the first remaining pixel clusters, determine a largest inscribed circle that is enclosed within the pixel cluster, compare a diameter of the largest inscribed circle with a threshold diameter corresponding to a dimension of a metal stud, and remove the pixel cluster from consideration as a welding site location if the diameter of the largest inscribed circle is less than the threshold diameter,
• identify second remaining pixel clusters comprising at least one pixel cluster whose diameter of the largest inscribed circle is equal to or greater than the threshold diameter,
• for each pixel cluster of the second remaining pixel clusters, determine a center of the largest inscribed circle that is enclosed within the pixel cluster as a center of the pixel cluster having an image-space coordinate, and convert the image-space coordinate to an object-space coordinate of a welding site location for a corresponding metal stud, and
• a controller configured to, for each pixel cluster of the second remaining pixel clusters, align a center of the corresponding metal stud with the object-space coordinate of the welding site location.