System for detecting ice or snow on surface which specularly reflects light
First Claim
1. A method for detecting on a surface which specularly reflects light, a presence of a polarization altering substance comprising the steps of:
- transmitting light over a transmitting path to said surface;
receiving said transmitted light over a receiving path for said transmitted light from said surface and from said substance alternately in optical isolator and optical nonisolator states;
measuring a first intensity of light received in said optical non-isolator state;
measuring a second intensity of light received in said optical isolator state; and
comparing said first and second intensities of received light to a plurality of reference data to detect the presence of said substance on said surface.
6 Assignments
0 Petitions
Accused Products
Abstract
A method and apparatus for detecting a presence of a polarization altering substance on a specular surface includes transmitting light to the surface over a transmitting path and receiving the transmitted light from the surface and from the polarization altering substance. An intensity of the light is measured in an optical non-isolator state and in an isolator state before being compared to reference data established for various specular surfaces. The reference data are preferably established by measuring an intensity of the light in both an optical non-isolator state and in an isolator state for a known surface when the polarization altering substance is absent from the known surface.
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Citations
26 Claims
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1. A method for detecting on a surface which specularly reflects light, a presence of a polarization altering substance comprising the steps of:
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transmitting light over a transmitting path to said surface; receiving said transmitted light over a receiving path for said transmitted light from said surface and from said substance alternately in optical isolator and optical nonisolator states; measuring a first intensity of light received in said optical non-isolator state; measuring a second intensity of light received in said optical isolator state; and comparing said first and second intensities of received light to a plurality of reference data to detect the presence of said substance on said surface. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. Apparatus for detecting on a surface which specularly reflects light, the presence of a polarization altering substance comprising:
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means for transmitting 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; optical means in at least one of said transmitting path and said receiving path; means for alternating said optical means between an optical non-isolator state and an optical isolator state; said means for receiving including means for measuring a first intensity of light received at said means for receiving when said optical means is in said optical non-isolator state, and means for measuring a second intensity of light received at said means for receiving when said optical means is in said optical isolator state; and means for comparing said first and second intensities of light to a plurality of reference data to detect the presence of said substance on said surface. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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24. Apparatus for detecting on a surface which specularly reflects light, the presence of a polarization altering substance comprising:
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means for transmitting 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; optical means in at least one of said transmitting path and said receiving path; means for alternating said optical means between an optical non-isolator state and an optical isolator state; means for measuring a first intensity of light received at said means for receiving when said optical means is in said optical non-isolator state and outputting a first logarithmic signal; means for measuring a second intensity of light received at said means for receiving when said optical means is in said optical isolator state and outputting a second logarithmic signal; means, responsive to a length of said receiving path, for range-correcting said first and second logarithmic signals; means for comparing said range-corrected second logarithmic signal to said range-corrected first logarithmic signal and outputting a ratio signal; means for calculating a threshold signal; and means for comparing said ratio signal to said threshold signal. - View Dependent Claims (25, 26)
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Specification