An imaging system includes a first off-axis illumination source for providing
a first illumination field at a surface of an illumination modulator such that
when the modulator is in a first non-activated mode a zero-order reflected illumination
field is directed toward a first illumination blocking device, and when the modulator
is in a second activated mode one first order reflected illumination field is directed
toward an imaging surface while another first order reflected illumination field
is directed toward a second illumination blocking device.