[WM]: Re: wavelet based watermarked

["Min-Su KIM" <speedyminsu@gmail.com>]

after forward WT, did you insert a bit like THIS?
W = W + M ?
,where W is detail coefficient, M is your random bits.

and if you did so, maybe, it was too big to be invisible.

Try like THIS,

W = W + alpha * M,

, where 0.0 < alpha <1.0

you can control the strength of your watermark more invisible with alpha.

or you can also try like THIS,

 W = W + alpha * M * W,

, where 0.0 < alpha <1.0.

You can see our BIBLE book, DIGITAL WATERMARKING from the the COX, the MILLER, and the BLOOM . :)

----- Original Message ----- 
From: "bo zambo" <bo_me_bo@yahoo.com>
To: <watermarking@watermarkingworld.org>
Sent: Wednesday, August 24, 2005 5:41 PM
Subject: [WM]: wavelet based watermarked


> dear watermarkers
> 
> I'm working on a wavelet based watermarked...I'm really new in this field and I have lot to ask...
> I try a simple wavelet based watermarked just decomposed the image and change the details coeffecients of the lowest level by
adding
> it with 1 or -1 (randomly) after that inverse DWT, the problem is...the watermarked image is not perceptual invisibility...can
> antone tell me why and rceptual invisibility...can
>how to fix this. I follow the step from some papers but the result is not the same. Am I miss some step? Ok
> thanks. please don't laugh,,I really new in these field,,,ok you can laugh but please answer my question.
> 
> regau can laugh but please answer my question.
>rds
> Bo
> 
> 


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