Multi-level retarder plate polarization dependent imaging
First Claim
1. A retarder plate for a television camera comprising:
- said camera including a plurality of pixels;
said retarder plate being disposed before said plurality of pixels;
a linear polarizer between said plurality of pixels and said retarder plate;
said retarder plate including a first plurality of first regions having a first optical thickness;
said retarder plate including a second plurality of second regions having a second optical thickness;
said first optical thickness and said second optical thickness differing from each other by a multiple of one quarter of an optical wavelength;
said first plurality being aligned before a first subset of said plurality of pixels; and
said second plurality being aligned before a second subset of said plurality of pixels, whereby said linear polarizer and said first and second regions produce two of left-hand polarization, right-hand polarization, and non-polarization.
5 Assignments
0 Petitions
Accused Products
Abstract
A system for detecting the presence of an energy polarization altering dielectric material, such as ice or snow, on a surface, such as a part of an aircraft, which normally specularly reflects incident energy, such as light, when there is no such dielectric present. The energy is conveyed from a transmitter along a path to the surface and the incident energy is reflected from the surface along a path to a receiver with a dielectric on the surface destroying any polarization, such as circular, of the energy and that reflected from a specular portion maintaining the polarization. An optical system in one or both of the paths operates in an isolator state to produce an image of the dielectric portion having a first intensity level and that of the specular portion passing through the optical system having a different intensity level. When the optical system is operated alternately in isolator and non-isolator states it produces an image of the dielectric portion having a relatively steady intensity level and that of the specular portion alternating between first and second different intensity levels corresponding to the isolator and non-isolator states of the optical system.
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Citations
4 Claims
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1. A retarder plate for a television camera comprising:
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said camera including a plurality of pixels; said retarder plate being disposed before said plurality of pixels; a linear polarizer between said plurality of pixels and said retarder plate; said retarder plate including a first plurality of first regions having a first optical thickness; said retarder plate including a second plurality of second regions having a second optical thickness; said first optical thickness and said second optical thickness differing from each other by a multiple of one quarter of an optical wavelength; said first plurality being aligned before a first subset of said plurality of pixels; and said second plurality being aligned before a second subset of said plurality of pixels, whereby said linear polarizer and said first and second regions produce two of left-hand polarization, right-hand polarization, and non-polarization. - View Dependent Claims (2, 3)
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4. A television system comprising:
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a color television camera from which color filtering for red (R), green (G) and blue (B) colors has been removed; a retarder plate in front of said color television camera; a linear polarizer between said color television camera and said retarder plate; said retarder plate including a plurality of first regions, corresponding to said color filtering for red; said retarder plate including a plurality of second regions, corresponding to said color filtering for green; said retarder plate including a plurality of third regions, corresponding to said color filtering for blue; said first regions having an optical thickness equal to an integral multiple of a half wavelength of light, minus one quarter wavelength; said second regions having an optical thickness equal to an integral multiple of a half wavelength of light; and said third regions having an optical thickness equal to an integral multiple of a half wavelength of light, plus one quarter wavelength.
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Specification