초록 ▼

A presence of a polarization altering substance on a specular surface is detected by transmitting light from a single strobed light source to the surface over a transmitting path and receiving the transmitted light from the surface. An intensity of the light is measured in both an optical non-isolat

A presence of a polarization altering substance on a specular surface is detected by transmitting light from a single strobed light source to the surface over a transmitting path and receiving the transmitted light from the surface. An intensity of the light is measured in both an optical non-isolator state and an isolator state by a same detector by delaying the non-isolated return light for a definite period of time before measuring it with the detector. The measured isolated and non-isolated intensities are converted to logarithmic form, range corrected, and compared to reference data established for the specific specular surface being investigated to detect the presence or absence of the polarization altering substance. Attenuation and backscattering effects of scattering and/or absorbing interference in the transmitted light are compensated so that the reference table is entered at the correct point. Using different intensities of transmitted light increases the dynamic range of the system.

대표청구항 ▼

[ What is claimed is:] [1.] Apparatus for detecting, on a surface which specularly reflects light, the presence of a polarization altering substance on said surface comprising:means for transmitting a pulse of light over a transmitting path to said surface;means for receiving transmitted light;a rec

[ What is claimed is:] [1.] Apparatus for detecting, on a surface which specularly reflects light, the presence of a polarization altering substance on said surface comprising:means for transmitting a pulse of light over a transmitting path to said surface;means for receiving transmitted light;a receiving path for said transmitted light from said surface and from said substance to said means for receiving;means for splitting said transmitted light into a non-isolated portion and an isolated portion;means for delaying one of said non-isolated portion and said isolated portion relative to another thereof to produce a first-to-arrive signal and a second-to-arrive signal;said first-to-arrive signal being completed at an output of said means for delaying before said second-to-arrive signal arrives at said output;means for measuring a first intensity of said first-to-arrive signal and outputting a first signal;means for measuring a second intensity of light of said second-to-arrive signal and outputting a second signal; andmeans for comparing said first and second intensities of light to reference data to detect the presence of said substance on said surface.