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  2. Discrete cosine transform - Wikipedia

    en.wikipedia.org/wiki/Discrete_cosine_transform

    A discrete cosine transform (DCT) expresses a finite sequence of data points in terms of a sum of cosine functions oscillating at different frequencies.The DCT, first proposed by Nasir Ahmed in 1972, is a widely used transformation technique in signal processing and data compression.

  3. List of transforms - Wikipedia

    en.wikipedia.org/wiki/List_of_transforms

    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 Chebyshev transform. Equivalent, up to a diagonal scaling, to ...

  4. Discrete transform - Wikipedia

    en.wikipedia.org/wiki/Discrete_transform

    Many common integral transforms used in signal processing have their discrete counterparts. For example, for the Fourier transform the counterpart is the discrete Fourier transform. In addition to spectral analysis of signals, discrete transforms play important role in data compression, signal detection, digital filtering and correlation ...

  5. Trigonometric interpolation - Wikipedia

    en.wikipedia.org/wiki/Trigonometric_interpolation

    The sine-only expansion for equally spaced points, corresponding to odd symmetry, was solved by Joseph Louis Lagrange in 1762, for which the solution is a discrete sine transform. The full cosine and sine interpolating polynomial, which gives rise to the DFT, was solved by Carl Friedrich Gauss in unpublished work around 1805, at which point he ...

  6. Mel-frequency cepstrum - Wikipedia

    en.wikipedia.org/wiki/Mel-frequency_cepstrum

    Take the discrete cosine transform of the list of mel log powers, as if it were a signal. The MFCCs are the amplitudes of the resulting spectrum. There can be variations on this process, for example: differences in the shape or spacing of the windows used to map the scale, [ 4 ] or addition of dynamics features such as "delta" and "delta-delta ...

  7. Transform coding - Wikipedia

    en.wikipedia.org/wiki/Transform_coding

    The most widely used transform coding technique in this regard is the discrete cosine transform (DCT), [1] [2] proposed by Nasir Ahmed in 1972, [3] [4] and presented by Ahmed with T. Natarajan and K. R. Rao in 1974. [5] This DCT, in the context of the family of discrete cosine transforms, is the DCT-II.

  8. Nasir Ahmed (engineer) - Wikipedia

    en.wikipedia.org/wiki/Nasir_Ahmed_(engineer)

    He is best known for inventing the discrete cosine transform (DCT) in the early 1970s. The DCT is the most widely used data compression transformation, the basis for most digital media standards (image, video and audio) and commonly used in digital signal processing. He also described the discrete sine transform (DST), which is related to the ...

  9. Sine and cosine transforms - Wikipedia

    en.wikipedia.org/wiki/Sine_and_cosine_transforms

    By applying Euler's formula (= ⁡ + ⁡), it can be shown (for real-valued functions) that the Fourier transform's real component is the cosine transform (representing the even component of the original function) and the Fourier transform's imaginary component is the negative of the sine transform (representing the odd component of the ...