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dctmtx

PURPOSE ^

% T = dctmtx (n)

SYNOPSIS ^

function T = dctmtx(n)

DESCRIPTION ^

% T = dctmtx (n)
%    Return the DCT transformation matrix of size n x n.
%
% If A is an n x n matrix, then the following are true:
%     T*A    == dct(A),  T'*A   == idct(A)
%     T*A*T' == dct2(A), T'*A*T == idct2(A)
%
% A dct transformation matrix is useful for doing things like jpeg
% image compression, in which an 8x8 dct matrix is applied to
% non-overlapping blocks throughout an image and only a subblock on the
% top left of each block is kept.  During restoration, the remainder of
% the block is filled with zeros and the inverse transform is applied
% to the block.
%
% See also: dct, idct, dct2, idct2

CROSS-REFERENCE INFORMATION ^

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