How to extract features of image using DCT??

I am working on a copy move forgery in which first i input the image then convert it in ycbcr colour code nd then make y component as input image and apply SWT on image. now can u plz help me how to apply DCT for extracting the features of this image. I am attaching my code.

clc
clear all
close all
I = imread('gun.png');
K = imresize(I,[256 256]);
ycbcr = rgb2ycbcr(K);
figure
imshow(ycbcr);
title('Image in RGB Color Space');
%a = 128+zeros(256,256);
    %Isolate Y. 
Y = ycbcr(:,:,1);
    %Isolate Cb. 
Cb = ycbcr(:,:,2);
    %Isolate Cr. 
Cr= ycbcr(:,:,3);
    
figure, imshow(Y), title('Y Component')
    %Display the Cb Component.
figure, imshow(Cb), title('Cb Component')
     %Display the Cr Component.
figure, imshow(Cr), title('Cr Component')
[ca,chd,cvd,cdd] = swt2(Y,2,'db6');
A1 = wcodemat(ca(:,:,1),255);
H1 = wcodemat(chd(:,:,1),255);
V1 = wcodemat(cvd(:,:,1),255);
D1 = wcodemat(cdd(:,:,1),255);
subplot(2,2,1)
image(A1)
title('Approximation Coef. of Level 1')

subplot(2,2,2)
image(H1)
title('Horizontal Detail Coef. of Level 1')

subplot(2,2,3)
image(V1)
title('Vertical Detail Coef. of Level 1')

subplot(2,2,4)
image(D1)
title('Diagonal Detail Coef. of Level 1')

[KALYAN ACHARJYA]

@Vaishali It would be better, if the question is specific. As "features word" is represent a broad sense in image processing domain, the features extraction are based on target application. See the examples Link1, Link2, Link3

[vaishali sharma]

i want to extract features of image using DCT and then used those feature for feature matching in order to locate copy move forged region