Optical angle of arrival measurement system and method
First Claim
1. An optical angle of arrival measurement system, comprising:
- a focal plane array (FPA) comprising an M row×
N column array of pixels, said rows and said columns being parallel to a row axis and a column axis, respectively; and
one or more optical elements, one of which is a diffractive optical element (DOE), arranged to converge incoming light from one or more point sources onto said FPA in a predetermined pattern of lines which are oblique with respect to the row and column axes of said FPA, such that the position of said lines on said FPA varies with the angular position of said point source(s) relative to said measurement system;
wherein said predetermined pattern of lines comprises two perpendicular narrow width lines that form a cross-pattern, each of said lines being oblique with respect to said row and column axes and traversing at least two of said rows or columns along their respective lengths.
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Accused Products
Abstract
An optical angle of arrival measurement system uses an optical element to form at least one narrow width line on a focal plane array (FPA) which is oblique with respect to the FPA'"'"'s row and column axes and which traverses at least two rows or columns along its length; forming two perpendicular narrow width lines in a cross-pattern is preferred. Interpolating the position of the lines on the FPA provides coordinates that can be used to calculate the optical angle of arrival in accordance with θx=A(x)·tan−1(x/f), and θy=B(y)·tan−1(y/f), where f is the focal length of the optical element, and A(x) and B(y) are parameters that account for optical distortion and other imperfections of the system. The resolution δθ of the angle of arrival measurement can be improved to at least δθ˜(d/n)/f, where d is the FPA pixel width and n is the length in pixels of the imaged line.
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Citations
22 Claims
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1. An optical angle of arrival measurement system, comprising:
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a focal plane array (FPA) comprising an M row×
N column array of pixels, said rows and said columns being parallel to a row axis and a column axis, respectively; andone or more optical elements, one of which is a diffractive optical element (DOE), arranged to converge incoming light from one or more point sources onto said FPA in a predetermined pattern of lines which are oblique with respect to the row and column axes of said FPA, such that the position of said lines on said FPA varies with the angular position of said point source(s) relative to said measurement system; wherein said predetermined pattern of lines comprises two perpendicular narrow width lines that form a cross-pattern, each of said lines being oblique with respect to said row and column axes and traversing at least two of said rows or columns along their respective lengths. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. An optical angle of arrival measurement system, comprising:
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a focal plane array (FPA) comprising an M row×
N column array of pixels, said rows and said columns being parallel to a row axis and a column axis, respectively; andone or more optical elements which include first and second orthogonal uniaxial birefringent cylindrical lens assemblies arranged to converge polarized incoming light from one or more point sources onto said FPA, said first birefringent cylindrical lens assembly having a focusing power in the x-direction for the x-polarization component of the light only and said second birefringent cylindrical lens assembly having a focusing power in the y-direction for y-polarization component of the light only, said first and second orthogonal uniaxial birefringent cylindrical lens assemblies arranged such that incoming light from said one or more point sources converges onto said FPA as two perpendicular narrow width lines, each of which is oblique with respect to said row and column axes and traverses at least two of said rows or columns along its length, such that the position of said lines on said FPA varies with the angular position of said point source(s) relative to said measurement system. - View Dependent Claims (21)
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22. An optical angle of arrival measurement system, comprising:
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a focal plane array (FPA) comprising an M row×
N column array of pixels, said rows and said columns being parallel to a row axis and a column axis, respectively; andone or more optical elements which include first and second orthogonal uniaxial birefringent cylindrical lens assemblies arranged to converge polarized incoming light from one or more point sources onto said FPA, said first birefringent cylindrical lens assembly having a focusing power in the x-direction for the x-polarization component of the light only and said second birefringent cylindrical lens assembly having a focusing power in the y-direction for y-polarization component of the light only, said first and second orthogonal uniaxial birefringent cylindrical lens assemblies arranged such that incoming light from said one or more point sources converges onto said FPA as two perpendicular narrow width lines, each of which is oblique with respect to said row and column axes and traverses at least two of said rows or columns along its length, such that the position of said lines on said FPA varies with the angular position of said point source(s) relative to said measurement system; wherein each of said first and second orthogonal uniaxial birefringent cylindrical lens assemblies comprises a positive cylindrical lens formed from birefringent material and a negative cylindrical lens formed from an isotropic material.
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Specification