Reconstruct the initial image with idct2

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Damien Dubois
Damien Dubois 2021-6-17
评论： Damien Dubois 2021-6-20
Hello, for an assignment I needed to create an image of 512x512 pixels black with in its center a square of white pixel of 100pixels, then I had to make its transformation into discrete cosine and now I must thanks to the function idct2, reconstruct the initial image by retaining only :
  • The 80% largest coefficients of the DCT
  • The 50% largest coefficients of the DCT
  • The 20% largest coefficients of the DCT
But I don't know how to set this parameter, here is my code currently.
image=zeros(512,512);
image(206:305,206:305)=255;
J = dct2(image);
imshow(log(abs(J)),[])
colormap parula
colorbar

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采纳的回答

Jonas
Jonas 2021-6-19
编辑：Jonas 2021-6-19
have a look into this post
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Jonas
Jonas 2021-6-20
your code is correct. it will remove all values that are smaller than 75% border of absolute values. you can change it to 80, 50 (which is the median by the way!) and 20 to achieve your original goal according to your question

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