Patent ID: 7948682

Claim:
An apparatus comprising: a first portion having optics configured to route a selected waveband of radiation along a path of travel passing successively through spaced first, second and third locations with a selected field of view, said optics causing first radiation within said selected waveband to travel from said first location to said third location along said path of travel within said selected field of view; and a second portion including a filtering structure, transmissive to radiation within a passband, disposed along said path of travel and a radiation generator which emits second radiation within said selected waveband, wherein said filtering structure introduces said second radiation, which falls within the passband, into said field of view at said second location and reflects said first radiation, except for a portion of the first radiation that falls within the passband, said second radiation thereafter traveling with said first radiation, less the portion that fell within the passband, from said second location to said third location along said path of travel.