{HEAD ~ The method} includes emitting light rays from each light source in a set of at least four light sources in a serial manner, and reflecting {TAIL ~ at least a portion} of the light rays emitted from each of the light sources from an encoded scale 
{ HEAD ~ The method } includes emitting light rays from each light source in a set of at least four light sources in a serial manner , and reflecting { TAIL ~ at least a portion } of the light rays emitted from each of the light sources from an encoded scale
HEAD HEAD HEAD HEAD HEAD HEAD REL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH