idct2() - Image Processing

B = idct2(A) returns the
two-dimensional inverse discrete cosine transform (DCT) of A.B = idct2(A,m,n) pads A with
0's to size m-by-n before transforming.
If [m n] < size(A), idct2 crops A before
transforming.B = idct2(A,[m n]) same
as above.For any A, idct2(dct2(A)) equals A to
within roundoff error.

Syntax

B = idct2(A)B = idct2(A,m,n)B = idct2(A,[m n])

Example

RGB = imread('autumn.tif');
I = rgb2gray(RGB);
J = dct2(I);
imshow(log(abs(J)),[]), colormap(jet), colorbar

Output / Return Value

Limitations

Alternatives / See Also

Reference