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Discrete cosine transform .. help!!

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Ahmed Ragab

Ahmed Ragab

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Any one has any pdf's on the discrete cosine transform?
i need to get data about the definition, basis function, inverse , fast algorithms
Thanks for all.
 

Refer any book on Digital Image Processing. You will find many transform coding techniques including Discrete Cosine transform for image compression. You may also search the forum for Digital Image Processing by Pratt.
 

Ahmed Ragab said:
Any one has any pdf's on the discrete cosine transform?
i need to get data about the definition, basis function, inverse , fast algorithms
Thanks for all.
Click to expand...

reg. the boks there are plenty availkable here itself...




and many moire...

/cedance
 

you can also refer to the JPEG and MPEG standards as the basis of these compression is DCT only. These groups maintain their own sites and u can easily find them by searching thru google
regards,
kunal
 

DCT is getting out of phase. DWT is getting its way into digital image and video processing such as JPEG-2000, H.264, etc.
 

The professor under whom Iam working has done a paper which is a reconfigurable architecture in which all known transforms are done in terms of DCT and DST..If you find that this could help you i can upload that paper.

Regards
drdolittle :)
 

Yes DrDolittle I think this article will be interesting .

Best Regards
dora
 

Rao(from U. Texas Ausdin) wrote a book on fast discret cosine tranform and its application. It was published about 15 years ago. You oculd find it in the local university library.
 

K. R. Rao is with U of Texas at Arlington, not Austin. He discovered the DCT with N. Ahmed (now with UNM).
 

Re: Discrete time dsp in matlab... help!!

eg. i have x(n)={...,0,0,1,2,1,-1,0,0...} i want to fft this signal when N=4,8,16
[X(k)=?] in matlab.and i couldn't.would you mind helping me quickly? thanks:)
 

I am guessing you use the function fft(x,n) where n is 4,8,.. and x is the array u define..

FFT(X,N) is the N-point FFT, padded with zeros if X has less
than N points and truncated if it has more.

hope this helps
 

fftw project on the internet maybe can help you.
It is a project of the group of fft .
Maybe it will have the DCT.
 


The best way to learn about Discrete Transform is to read any book of Image Processing.
If you want to learn how DCT is used specifically in image compression then the best thing to start with is JPEG standard
You can be in touch with jpeg on



In addition H.264 has new 4x4 integer transform which is basically derived from actual DCT.

There are lots of fast DCT algorithms and you can easily search fast DCT algorithms on google.

I will look into my repository if i get something for you

-Regards
 

I have done a lot of DCT fast implementation and test, including DCT8x8, DCT4x4, DCT248. Please check the attached source code. Hope it is helpful
 

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