Electro-optic ice detection
First Claim
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1. A method of indicating the presence of ice on a surface, comprising the following steps:
- detecting the intensity of reflected light from said surface at a first lower wavelength band, said lower band being within a band extending from about 1.1 microns to about 1.3 microns;
detecting the intensity of reflected light from said surface at a second upper wavelength band having substantially the same bandwidth as said lower band, said upper band being within a band extending from about 1.16 microns to about 1.3 microns; and
determining the presence or absence of ice on said surface based upon the intensity of reflected light at said first band and the intensity of reflected light at said second band.
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Abstract
To determine whether ice is present on an aircraft wing, the intensity of light in a band between 1.16 and 1.20 microns is determined as is the intensity in a band between 1.24 and 1.28 microns. The contrast, defined as the difference between the intensities over the sum of these intensities, is determined. Because of the peculiar characteristics of the reflectivity of ice, water, Type I de-icing fluid, and Type II anti-icing fluid, if the contrast is positive, it is an indication of ice on the wing whereas if it is negative it is an indication there is no ice present.
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Citations
24 Claims
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1. A method of indicating the presence of ice on a surface, comprising the following steps:
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detecting the intensity of reflected light from said surface at a first lower wavelength band, said lower band being within a band extending from about 1.1 microns to about 1.3 microns; detecting the intensity of reflected light from said surface at a second upper wavelength band having substantially the same bandwidth as said lower band, said upper band being within a band extending from about 1.16 microns to about 1.3 microns; and determining the presence or absence of ice on said surface based upon the intensity of reflected light at said first band and the intensity of reflected light at said second band.
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2. A method of indicating the presence of ice on an aircraft surface, comprising the following steps:
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detecting the intensity of reflected light from said surface at a first lower wavelength band, said lower band being within a band extending from about 1.16 microns to about 1.24 microns; detecting the intensity of reflected light from said surface at a second upper wavelength band having substantially the same bandwidth as said lower band, said upper band being within a band extending from about 1.24 microns to about 1.29 microns; and determining the presence or absence of ice on said surface based upon the intensity of reflected light at said first band and the intensity of reflected light at said second band. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. Apparatus for determining the presence of ice on a surface, comprising the following:
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bandpass filter means configured to pass light within a first lower wavelength band, said lower band being within a band extending from about 1.1 microns to about 1.3 microns and within a second upper wavelength band having substantially the same bandwidth as said lower band, said upper band being within a band extending from about 1.16 microns to about 1.3 microns, said bandpass filter means for receiving light reflected from said surface; means for detecting the intensity of light passed through said bandpass filter means; and means responsive to said detecting means for determining the presence or absence of ice on said surface. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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Specification