An apparatus for classifying articles may include a frame connected to (1) transport means for directing articles to create a product stream, (2) an emitter section having a radiation source and (3) a detection section for detecting a portion of radiation reflected by articles. The detection section may include first detection means for converting radiant power of reflected radiation having a first polarization state into a first electrical signal, second detection means for converting radiant power of reflected radiation having a second polarization state into a second electrical signal, and third detection means for converting radiant power of reflected radiation into a third electrical signal. Control circuitry, which may receive the electrical signals, may include decision means for generating a selection signal. Selection means may separate an article from the product stream according to the received selection signal from the control circuitry.