An article of footwear provided with snap-fit replaceable ground-engaging members, particularly snap-fit tips, and a kit and method for altering ground-engaging characteristics of an article of footwear such as an athletic shoe. The fiber optic interface devices have a ferrule with a bore that supports an optical waveguide. A positioning and cutting assembly adjusts the position of the receiving cup to a cutting position with the head down and stem up and rotates the receiving cup. A memory may store the detected topography. The beater rotates about an axis generally transverse relative to the combine and is divided asymmetrically along its length into a number of sections corresponding to the number of streams of crop, each section of the beater having differently angled crop feeding members which direct crop towards a crop steam. Differential coded modulation is then performed on the extracted color values to further reduce image data size.