phash - matlab code for perceptual hashing -

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I need a matlab code here for the conceptual hashing algorithm:

Actually I remove it Want to delay an image and leave only information about the key structure components.

To do this, I think I need the following steps: 1. Reduce the DCT. Let's say the DCT is 32x32 (), just keep the top-left 8x8. They represent the lowest frequencies in the picture. Calculate the average value, like the average hash, the average DCT value (using only 8x8 DCT low frequency values ​​and excluding the first term, the DC coefficient other Calculate the values ​​can be quite different and the average will be off).

  • Reduce further DCT to determine 64 thousand bits based on 0 or 1 depending on whether the average of 64 dct values ​​is above or below each average value. The result does not tell us the actual low frequencies; It only tells the attacks the many relative values ​​of the frequencies, the result will not be different unless the overall structure of the image remains the same; It can avoid gamma and color histogram adjustments without problems.

  • Rebuilding the image after processing.

    • Can anyone help any one of the above steps? I have tried some code which gives some results (in the link below), it is not correct yet:

    Try it out:

    Read the image I = imread ('cameraman.tif'); % Cosine result and decrease D = DCT2 (I); D = D (1: 8,1: 8); % Calculation average a = mean (mean (d)); % Set bits, here's the ambiguity that & gt; Or & gt; = Will be used b = d & gt; a; % Maybe change to string: string = num2str (b (:) ');

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