image compressing with DCT

what is the coding Elimination of DCT coefficients for jpeg image compression ?? i using matlab R2008a

help me..

[Walter Roberson]

I do not understand this question as phrased, unless it is a duplicate of your other question http://www.mathworks.com/matlabcentral/answers/21891-jpeg-image-compressing-with-dct

Answer 1

[Hamrit]

dvalue=imread('yourimage');
dvalue = double(dvalue)/255;
dvalue = rgb2gray(dvalue);
imshow(dvalue)
img_dct=dct2(dvalue);
img_pow=(img_dct).^2;
img_pow=img_pow(:);
[B,index]=sort(img_pow);%no zig-zag
B=flipud(B);
index=flipud(index);
compressed_dct=zeros(size(dvalue));
coeff = 20000;% maybe change the value
for k=1:coeff
compressed_dct(index(k))=img_dct(index(k));
end
im=idct2(compressed_dct);

imwrite(im, 'Hassan.jpg')

not for color Jpeg