Converting DFT samples to DCT

[barath_87]

I require some materials regarding converting dft samples to dct .Pls help.
Thanks in advance.

 

[armin]

DFT to DCT???

Hi
assume that your signal is u for n=0,1,...,N-1
& that DCT{u}=v(k) for k=0,1,...,N-1

now define s such that:
s=u(2n) ]
] for n=0,1,...,N/2 -1
s(N-n-1)=u(2n+1) ]

now it is shown that:
v(k)=RE{a(k).exp(-j.pi.k/(2N)).DFT{s(n}}

----------------------------------------------
in other words,if we denote DFT{s} by h(k),then

v(k)=RE{a(k).exp(-j.pi.k/(2N)).h(k)} (in k domain)
&
s=u(2n) ]
] for n=0,1,...,N/2 -1(in n domain)
s(N-n-1)=u(2n+1) ]

----------------------------------------------------

for more detailed discussion i refer you to
"fundamentals of digital image processing" by Jain

ofvcourse there are many other refrences

hope it helped
Armin

 

[kastantin]

Re: DFT to DCT???

check
https://www.mathworks.com/matlabcentral/fileexchange/loadFile.do?objectId=13693&objectType=File