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I have an RGB image 512x512, and a 64x64 Watermark image which embedded with DWT, SVD.

watermarked image is 512x512 and double. extracted image is good (bit error rate=0).

But when I use imnoise with d=0, the extracted image is not good and BER=58%!

What is causing this and how can I prevent this error?

watermarked_image_attack=double(imnoise(uint8(Watermarked_Image),'salt & pepper', 0));
Recovered_message=Extracting_attacked_image(watermarked_image_attack,'db1',0.05);
Cris Luengo
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Marzi.KP
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  • You convert to `uint8`, likely destroying most information in the image. – Cris Luengo Jul 27 '19 at 14:52
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    If you want more help than this, you’ll have to include a [mre]. – Cris Luengo Jul 27 '19 at 14:55
  • converted to uint8 because imnoise accept just uint8. – Marzi.KP Jul 28 '19 at 08:10
  • That is not true. The documentation says “imnoise expects pixel values of data type double and single to be in the range [0, 1]. You can use the rescale function to adjust pixel values to the expected range. If your image is type double or single with values outside the range [0,1], then imnoise clips input pixel values to the range [0, 1] before adding noise.” – Cris Luengo Jul 28 '19 at 13:11

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