Is there a function in MATLAB to calculate higher DCTs like DCT-III, IV etc?

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sahil sharma 2022-10-13

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回答： Matt J 2022-10-13

I have started learning DCT recently. I know the function dct() and dct2() are used to calculated 1-D and 2-D DCT-II repectively. Is there any function that is used to calculate the DCT-III or DCT-IV? idct() is based on DCT-III but it is not going forward into DCT domain.

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Answer 1

Matt J 2022-10-13

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https://ww2.mathworks.cn/matlabcentral/answers/1825498-is-there-a-function-in-matlab-to-calculate-higher-dcts-like-dct-iii-iv-etc#answer_1074158

You can check the File Exchange, e.g.,

https://www.mathworks.com/matlabcentral/fileexchange/24050-multidimensional-discrete-cosine-transform-dct?s_tid=srchtitle

https://www.mathworks.com/matlabcentral/fileexchange/26040-dct-and-dst-inverse-in-arbitrary-dimension?s_tid=srchtitle

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Answer 2

Matt J 2022-10-13

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编辑：Matt J 2022-10-13

在 MATLAB Online 中打开

I don't think so, but you can always build one from fft().

function Y=dctn(X)
    d=size(X);
    n=numel(d);
    subs0=repmat({':'},1,n);
    
 Y=X;
 for i=1:n
     
     subs=subs0;
     subs{i}=1:d(i);
     
     Y=fft( cat(i,Y,flip(Y,i))  ,[],i);
     Y=real(Y(subs{:});
     
 end
  
end