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  2. Top-hat transform - Wikipedia

    en.wikipedia.org/wiki/Top-hat_transform

    In mathematical morphology and digital image processing, a top-hat transform is an operation that extracts small elements and details from given images.There exist two types of top-hat transform: the white top-hat transform is defined as the difference between the input image and its opening by some structuring element, while the black top-hat transform is defined dually as the difference ...

  3. Rectangular function - Wikipedia

    en.wikipedia.org/wiki/Rectangular_function

    Plot of normalized ⁡ function (i.e. ⁡ ()) with its spectral frequency components.. The unitary Fourier transforms of the rectangular function are [2] ⁡ = ⁡ = ⁡ (), using ordinary frequency f, where is the normalized form [10] of the sinc function and ⁡ = ⁡ (/) / = ⁡ (/), using angular frequency , where is the unnormalized form of the sinc function.

  4. Projection-slice theorem - Wikipedia

    en.wikipedia.org/wiki/Projection-slice_theorem

    In N dimensions, the projection-slice theorem states that the Fourier transform of the projection of an N-dimensional function f(r) onto an m-dimensional linear submanifold is equal to an m-dimensional slice of the N-dimensional Fourier transform of that function consisting of an m-dimensional linear submanifold through the origin in the Fourier space which is parallel to the projection ...

  5. Convolution for optical broad-beam responses in scattering ...

    en.wikipedia.org/wiki/Convolution_for_optical...

    For a top-hat beam, the upper integration limits may be bounded by r max, such that r ≤ r max − R. Thus, the limited grid coverage in the r direction does not affect the convolution. To convolve reliably for physical quantities at r in response to a top-hat beam, we must ensure that r max in photon transport methods is large enough that r ...

  6. Top-hat filter - Wikipedia

    en.wikipedia.org/wiki/Top-hat_filter

    In real-space the filter performs nearest-neighbour filtering, incorporating components from neighbouring y-function values. Despite its ease of implementation, its practical use is limited as the real-space representation of a top-hat filter is the sinc function, which has the often undesirable effect of incorporating non-local frequencies.

  7. Computer-generated holography - Wikipedia

    en.wikipedia.org/wiki/Computer-generated_holography

    Computer-generated holography (CGH) is a technique that uses computer algorithms to generate holograms.It involves generating holographic interference patterns.A computer-generated hologram can be displayed on a dynamic holographic display, or it can be printed onto a mask or film using lithography. [1]

  8. Sombrero function - Wikipedia

    en.wikipedia.org/wiki/Sombrero_function

    The factor of 2 is also often omitted, giving yet another definition and causing the function maximum to be 0.5: [3] ⁡ = (). The Fourier transform of the 2D circle function ( circ ⁡ ( ρ ) {\displaystyle \operatorname {circ} (\rho )} ) is a sombrero function.

  9. Rotation matrix - Wikipedia

    en.wikipedia.org/wiki/Rotation_matrix

    Every 3 × 3 rotation matrix is produced by two opposite points on the sphere. Correspondingly, the fundamental group of SO(3) is isomorphic to the two-element group, Z 2 . We can also describe Spin(3) as isomorphic to quaternions of unit norm under multiplication, or to certain 4 × 4 real matrices, or to 2 × 2 complex special unitary ...