Patent ID: 8553069

Claim:
A method of obtaining a rectilinear image, the method comprising: acquiring an uncorrected image plane using a camera equipped with a wide-angle lens rotationally symmetric about an optical axis; and extracting a processed image plane from the uncorrected image plane, wherein, the uncorrected image plane is a two dimensional array with K max , rows and L max columns, a pixel coordinate of the optical axis on the uncorrected image plane is (K o , L o ), a real projection scheme of the lens is an image height r obtained as a function of a zenith angle θ of a corresponding incident ray and given as r=r(θ), a magnification ratio g of the camera is given as g = r ′ r , wherein r′ is a pixel distance on the uncorrected image plane corresponding to the image height r, the processed image plane is a two dimensional array with I max rows and J max columns, a pixel coordinate of the optical axis on the processed image plane is (I o -ΔI, J o -ΔJ), wherein (I o , J o ) is given as ( I o , J o ) = ( 1 + I max 2 , I + J max 2 ) , and ΔI and ΔJ are arbitrary pixel distances, a video signal value for the pixel having a coordinate (I, J) on the processed image plane is given as a video signal value of an imaginary pixel on the uncorrected image plane having a coordinate (x′ I,J -y′ I,J ), wherein the pixel coordinate (x′ I,J -y′ I,J ) of the imaginary pixel is given by a following set of equations s ″ = J max - 1 2 ⁢ ⁢ tan ⁡ ( Δ ⁢ ⁢ ψ 2 ) θ I , J = tan - 1 ⁢ { ( I - I o + Δ ⁢ ⁢ I ) 2 + ( J - J o + Δ ⁢ ⁢ J ) 2 s ″ } ϕ I , J = tan - 1 ⁡ ( I - I o + Δ ⁢ ⁢ I J - J o + Δ ⁢ ⁢ J ) X I , J = sin ⁢ ⁢ θ I , J ⁢ cos ⁢ ⁢ ϕ I , J Y I , J = sin ⁢ ⁢ θ I , J ⁢ sin ⁢ ⁢ ϕ I , J Z I , J = cos ⁢ ⁢ θ I , J X I , J ″ = X I , J ⁢ cos ⁢ ⁢ β + Y I , J ⁢ sin ⁢ ⁢ β ⁢ ⁢ sin ⁢ ⁢ α + Z I , J ⁢ sin ⁢ ⁢ βcos ⁢ ⁢ α Y I , J ″ = Y I , J ⁢ cos ⁢ ⁢ α - Z I , J ⁢ sin ⁢ ⁢ α Z I , J ″ = - X I , J ⁢ sin ⁢ ⁢ β + Y I , J ⁢ cos ⁢ ⁢ β ⁢ ⁢ sin ⁢ ⁢ α + Z I , J ⁢ cos ⁢ ⁢ β ⁢ ⁢ cos ⁢ ⁢ α θ I , J = cos - 1 ⁡ ( Z I , J ″ ) ϕ I , J ⁢ = tan - 1 ⁡ ( Y I , J ″ X I , J ″ ) r I , J = r ⁡ ( θ I , J ) ⁢ ⁢ x I , J ′ = L o + g ⁢ ⁢ r I , J ⁢ cos ⁢ ⁢ ( ϕ I , J ) ⁢ ⁢ y I , J ′ = K o + g ⁢ ⁢ r I , J ⁢ sin ⁡ ( ϕ I , J ) wherein Δψ is an arbitrary angle smaller than 180°, and α and β are arbitrary angles.