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