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  2. Frame (linear algebra) - Wikipedia

    en.wikipedia.org/wiki/Frame_(linear_algebra)

    The frame condition was first described by Richard Duffin and Albert Charles Schaeffer in a 1952 article on nonharmonic Fourier series as a way of computing the coefficients in a linear combination of the vectors of a linearly dependent spanning set (in their terminology, a "Hilbert space frame"). [4]

  3. Flat-field correction - Wikipedia

    en.wikipedia.org/wiki/Flat-field_correction

    This picture is darker at the edges. This variation is called vignetting , and can be corrected by selectively brightening the perimeter of the image. Flat-field correction ( FFC ) is a digital imaging technique to mitigate the image detector pixel-to-pixel sensitivity and distortions in the optical path .

  4. Fundamental matrix (computer vision) - Wikipedia

    en.wikipedia.org/wiki/Fundamental_matrix...

    In computer vision, the fundamental matrix is a 3×3 matrix which relates corresponding points in stereo images.In epipolar geometry, with homogeneous image coordinates, x and x′, of corresponding points in a stereo image pair, Fx describes a line (an epipolar line) on which the corresponding point x′ on the other image must lie.

  5. Periodic boundary conditions - Wikipedia

    en.wikipedia.org/wiki/Periodic_boundary_conditions

    Periodic boundary conditions in 2D Unit cell with water molecules, used to simulate flowing water. Periodic boundary conditions (PBCs) are a set of boundary conditions which are often chosen for approximating a large (infinite) system by using a small part called a unit cell. PBCs are often used in computer simulations and mathematical models.

  6. Rotation matrix - Wikipedia

    en.wikipedia.org/wiki/Rotation_matrix

    Because this equation holds for all vectors, p, one concludes that every rotation matrix, Q, satisfies the orthogonality condition, Q T Q = I . {\displaystyle Q^{\mathsf {T}}Q=I.} Rotations preserve handedness because they cannot change the ordering of the axes, which implies the special matrix condition,

  7. Parallel transport - Wikipedia

    en.wikipedia.org/wiki/Parallel_transport

    A linear isomorphism is determined by its action on an ordered basis or frame. Hence parallel transport can also be characterized as a way of transporting elements of the (tangent) frame bundle GL(M) along a curve. In other words, the affine connection provides a lift of any curve γ in M to a curve γ̃ in GL(M).

  8. Otsu's method - Wikipedia

    en.wikipedia.org/wiki/Otsu's_method

    An example image thresholded using Otsu's algorithm Original image. In computer vision and image processing, Otsu's method, named after Nobuyuki Otsu (大津展之, Ōtsu Nobuyuki), is used to perform automatic image thresholding. [1]

  9. Foreground detection - Wikipedia

    en.wikipedia.org/wiki/Foreground_detection

    The following analyses make use of the function of V(x,y,t) as a video sequence where t is the time dimension, x and y are the pixel location variables. e.g. V(1,2,3) is the pixel intensity at (1,2) pixel location of the image at t = 3 in the video sequence.