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Re: [WM]: RST_watermarking
Dear Serap,
In the algorithm proposed by Ruanaidh (1997), the FFT magnitude must be shifted at the centre of the image, before computing the LPM
in the forward process. Since LPM and ILPM cause distortions, owing to interpolation and round-off errors, the frequencies of you
image can be significantly modified (specially the higher ones).
Those are the only distortions your image should undergo. As far as I know, the image brightness should not be considerably
modified.
Best,
Sergio Bravo-Solorio
El vie, 09-02-2007 a las 13:37 +0200, Serap KAZAN escribió:
> Hello,
>
> I used RST for watermarking. I made FFT, LPM, FFT watermark and IFFT,
>ILPM and IFFT. But after these the image is not same the image at the begining= . It is darker. I don't know what to do. Can you
explain this.
>
> thanks
>
> Serap
>
>
>
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