BenRavin wrote:
> Hi,
> 
> I am looking for some technical information rgarding DCT. Why DCT is
> used in image/video/audio instead of transform like FFT? What
> information we get after taking a DCT? Is DCT just the real part of
> FFT? 
> 
> Please send me some info regarding this.

See the cartoon at the end of http://users.erols.com/jyavins/procfaq.htm.

Jerry
-- 
Engineering is the art of making what you want from things you can get.
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"BenRavin" <Biju.ushas@gmail.com> wrote in message
news:1140134103.811348.115560@f14g2000cwb.googlegroups.com...
> Hi,
>
> I am looking for some technical information rgarding DCT. Why DCT is
> used in image/video/audio instead of transform like FFT? What
> information we get after taking a DCT? Is DCT just the real part of
> FFT?
>
> Please send me some info regarding this.

http://en.wikipedia.org/wiki/Discrete_cosine_transform

It took me less than 15 secs to find this. It is taking me longer to write
this post. It probably took you even longer to write your first post.
Have you tried something called Google or perhaps you are new to all this
but I'll bet half my ass that AltaVista or Yahoo can do this just as good.
(sorry...I'm in a pissy mood from staring at an obscure spec written several
centuries back).

Cheers
Bhaskar

did you hit google first ?

DCT is just another transform, which also create bins of specific
frequency components.

dct(x) != real(fft(x))

so they are not the same.
DCT creates those frequency bins very similar to the way our eyes
handles the vision (Human vision is modelled better using DCT - atleast
till wavelets). So, if we figure out what frequencies are really
important for the eyes, we can throw away others, which is exactly the
DCT based compression in image/video does !! 

-mank

Hi,

I am looking for some technical information rgarding DCT. Why DCT is
used in image/video/audio instead of transform like FFT? What
information we get after taking a DCT? Is DCT just the real part of
FFT? 

Please send me some info regarding this.

Thanking you