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DCT and DST (+ inverse) in arbitrary dimension

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DCT and DST (+ inverse) in arbitrary dimension

by

Damien Garcia (view profile)

 

07 Dec 2009 (Updated )

Discrete cosine/sine transforms and their inverses

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Description

Y = DCTN(X) returns the discrete cosine transform (DCT) of X.

X = IDCTN(Y) returns the inverse discrete cosine transform (IDCT) of Y.

Y = DSTN(X) returns the discrete sine transform (DST) of X.

X = IDSTN(Y) returns the inverse discrete sine transform (IDST) of Y.

X and Y can be N-dimensional.

D = DSTMTX(k) returns the k-by-k DST transform matrix.

Faster DCT2 and IDCT2 are also included in the zip file.

Enter "help dctn", "help dstn", "help idctn", "help idstn" and "help dstmtx" in the Matlab command window for complete information.

Example
-------
RGB = imread('autumn.tif');
I = rgb2gray(RGB);
J = dstn(I);
imshow(log(abs(J)),[]), colormap(jet), colorbar
 
The commands below set values less than magnitude 10 in the DST matrix to zero, then reconstruct the image using the inverse DST.
 
J(abs(J)<10) = 0;
K = idstn(J);
figure, imshow(I)
figure, imshow(K,[0 255])

------
http://www.biomecardio.com/matlab
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Acknowledgements

This file inspired Inpaint Over Missing Data In 1 D, 2 D, 3 D,... N D Arrays.

MATLAB release MATLAB 7.5 (R2007b)
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Comments and Ratings (1)
09 Dec 2011 G. Sken

G. Sken (view profile)

these function when used in >resize3d< allow faster volume resizing of large volumes with less memory usage

Updates
09 Mar 2010 1.2

DCT and IDCT have been added upon request

23 Nov 2011 1.4

Faster DCT2 and IDCT2 are also included

25 Nov 2011 1.5

faster DCT2 and IDCT2 are also included

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