Discrete cosine transform DCT (urgent)

Dear all,

I am doing the palm print recognition.May i know is it somebody know how to calculate the DCT of the image?
i have try a few method....in the MATLAB..
i use the DCT or DCT2 in MATLAB but the result is not good....
I hope somebody can help me...
My source code is as below....I have try 3 method to calculate the DCT of image...

DCTfm1 = dct2(I);

max(max(DCTfm1))
min(min(DCTfm1))
ans =
18.0219
ans =
-6.2640
---------------------------------------------------------------------------------------------
logofDCT = log(DCTfm1);
max(max(logofDCT))
min(min(logofDCT))
ans =
-13.8896 + 3.1416i
ans =
-1.4010
---------------------------------------------------------------------------------------------
a = I;
b=im2col(a,[8 8],'distinct');
mean(b);
max(b);
a1=mean(b)./max(b);
[max_a1,k] = max(a1)

max_a1 =
0.2985
k =
87
--------------------------------------------------------------------------------------------

I want to ask whether which method above is better to used in the propagation of neural network.?May be i did wrong in my source code.....please guide me...

If you have any source code or file which related with the DCT or neural network, please e-mail to me....
yuna_free@yahoo.com

Please.............. i really hope somebody can guide me...

Thanks in advance.....

Hi ,
I think you need to go trough this book ,
Digital Image Proceessing in Matlab by Gonzales
They have sample program which does it also the working principle of DCT
Hope this helps...
Thanx