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  2. Hadamard transform - Wikipedia

    en.wikipedia.org/wiki/Hadamard_transform

    The Hadamard transform H m is a 2 m × 2 m matrix, the Hadamard matrix (scaled by a normalization factor), that transforms 2 m real numbers x n into 2 m real numbers X k.The Hadamard transform can be defined in two ways: recursively, or by using the binary (base-2) representation of the indices n and k.

  3. Image compression - Wikipedia

    en.wikipedia.org/wiki/Image_compression

    Image compression is a type of data compression applied to digital images, ... (FFT) coding in 1968 and the Hadamard transform in 1969. [10]

  4. Sum of absolute transformed differences - Wikipedia

    en.wikipedia.org/wiki/Sum_of_absolute...

    The sum of absolute transformed differences (SATD) is a block matching criterion widely used in fractional motion estimation for video compression.It works by taking a frequency transform, usually a Hadamard transform, of the differences between the pixels in the original block and the corresponding pixels in the block being used for comparison.

  5. List of transforms - Wikipedia

    en.wikipedia.org/wiki/List_of_transforms

    Fast Fourier transform, a popular implementation of the DFT; Discrete cosine transform. Modified discrete cosine transform; Discrete Hartley transform; Discrete sine transform; Discrete wavelet transform; Hadamard transform (or, Walsh–Hadamard transform) Fast wavelet transform; Hankel transform, the determinant of the Hankel matrix; Discrete ...

  6. Data compression - Wikipedia

    en.wikipedia.org/wiki/Data_compression

    Transform coding dates back to the late 1960s, with the introduction of fast Fourier transform (FFT) coding in 1968 and the Hadamard transform in 1969. [33] An important image compression technique is the discrete cosine transform (DCT), a technique developed in the early 1970s. [16]

  7. Hadamard product (matrices) - Wikipedia

    en.wikipedia.org/wiki/Hadamard_product_(matrices)

    The Hadamard product appears in lossy compression algorithms such as JPEG. The decoding step involves an entry-for-entry product, in other words the Hadamard product. [citation needed] In image processing, the Hadamard operator can be used for enhancing, suppressing or masking image regions. One matrix represents the original image, the other ...

  8. Hadamard matrix - Wikipedia

    en.wikipedia.org/wiki/Hadamard_matrix

    Let H be a Hadamard matrix of order n.The transpose of H is closely related to its inverse.In fact: = where I n is the n × n identity matrix and H T is the transpose of H.To see that this is true, notice that the rows of H are all orthogonal vectors over the field of real numbers and each have length .

  9. Sum of absolute differences - Wikipedia

    en.wikipedia.org/wiki/Sum_of_absolute_differences

    There are exactly three unique locations within the search image where the template may fit: the left side of the image, the center of the image, and the right side of the image. To calculate the SAD values, the absolute value of the difference between each corresponding pair of pixels is used: the difference between 2 and 2 is 0, 4 and 1 is 3 ...