劉晟志 2010/03/21 Homework 1. watermarking

Hide “nsysu logo” into the 3 rd bit plane

PSNR: dB OriginalPost

Discuss:  why can’t we extract the watermarking after doing the “Noise adding” by Photoshop?  Every pixel had been change during the process  The noise rate only decides the weight of the noise that will be add to every pixel  As the result, the watermarking can not avoid attack  Add black spot noise

Add black spot noise with different occur rate (gray level watermarking) 5% 10% 15% 20%

Add black spot noise with different occur rate (binary watermarking) 5% 10% 15% 20%

Different JPEG compress rate 5% 10% 15% 20% Cover image Water marking

Discuss:  why can’t we extract the watermarking after doing the “Noise adding” by Photoshop?  Every pixel had been change during the process  The noise rate only decides the weight of the noise that will be add to every pixel  As the result, the watermarking can not avoid this kind of noise attack

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