劉晟志2010/03 /21

Homework 1.watermarking

Hide “nsysu logo” into the 3rd bit plane

PSNR: 42.092 dB

Original Post

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

End