Re: [WM]: Query on Digital Watermarking

[zh_do@encs.concordia.ca]

Dear all,

When I using dwt2 to decompose a grayscale image, say 512 x 512 using bior4.4.
(I want to use the Daubechies 9/7, but there is no such functions in Matlab)

[CA, CH, CV, CD] = idw2(image_data, 'bior)

For the first level, the four band image is all 260 x 260!
and many intensities of CA is larger than 255!

I hope all the four band is 256 x 256, and CA is between 0 to 255. CV, CH, CD is no less than 0!  What is more, there should be no
information lost during the translation. Finally, I hope I can restore the image using idw2 command by these "normalized
CA,CH,CV,CD'



Thank you very much!!

Jeffery Dong



Quoting Vidyasagar Potdar <Vidyasagar.Potdar@cbs.curtin.edu.au>:

> Hello Vijayendra Gaur
> Its nice to hear that you are working on Watermarking Most of your 
> questions would be answered if you visit my website 
> http://www.ceebi.curtin.edu.au/~potdarv/
> As far as most implementation goes MATLAB is the preferred tool All 
> complex mathematical equations are inbuilt in MATLAB I have MATLAB 
> code for most of my watermarking algorithms which are based on 
> Wavelet.
> It might be helpful to you
> I recommend you go thru my papers which would give you an insight into 
> this field
>
> V. Potdar, S. Han, E. Chang, "A Survey of Digital Image Watermarking 
> Techniques",  in Proceedings of the 3rd International IEEE Conference 
> on Industrial Informatics, Perth, Western Australia, 10-12 Aug 2005
>
> V. Potdar, E. Chang, "Scalar Quantization based Robust Image 
> Watermarking Algorithm in the Wavelet Domain",  in ITC Conference, 
> Perth, Western Australia, 2005
>
> V. Potdar, S. Han, E. Chang, "Fingerprinted Secret Sharing 
> Steganography for Robustness against Image Cropping Attacks",  in 
> Proceedings of the 3rd International IEEE Conference on Industrial 
> Informatics, Perth, Western Australia, 10-12 Aug 2005 "Received Best 
> Paper (Presentation) Award and Invited for IEEE Transactions"
>
> If you need any have any more queries please feel free to contact me
>
> Regards.
>
>
>
> POTDAR Vidyasagar M.
>
> Doctoral Researcher and Associate Lecturer @ Curtin University of 
> Technology Address  214 Hill View Terrace, Bentley, Perth 6102
> Mobile    (+61) 04  2124 7048
> Office     (+61) 08  9266 3171 or 1057
> Web       http://www.ceebi.research.cbs.curtin.edu.au/~potdarv
>
> WINNER's don't do different things
>               They do things DIFFERENTLY
>
>>>> Vijayendra <viju_jaipur@yahoo.com> 11/30/2005 3:17 PM >>>
> Dear watermarkers
>
>  I am final year student of software engineering and i am doing a 
> project on Invisible Watermarking of Digital Images for Copyright 
> Protection but i do not have pre knowledge of this field but till now 
> i have done lot of research work on it and have gone through Digital 
> Image  Processing books. Now i am familiar with image like what is a 
> image and how to operate on them.
>
>    i wrote few programs like histogram equalization, median filter, 
> negative etc. using VC++ and Vision SDK tookit.
>
>  But i have few problems  as stated below-
>
>  1) As image processing is totaly mathematical so i am finding 
> difficulties in converting large mathematical equation into programs. 
> can any body tell me easiest way to do it.
>
>  2) i am not getting any idea on how to implement watermark on image
>
>
>  3) i will be using Haar Wavelet Transformation algorithm. But the 
> concept of Wavelet and Multiresolution band, Subband is not clear to 
> me.
>
>  4) What is a band in an image context. how can i understand it.
>
>  Can you guys help me out with some useful solution. ALso plz tell me 
> any site where i can get some sample programs in image manipulation 
> using VC++ platform.
>
>  Plz Guide me in my project...................
>
>
>  Thanking You
>
>
>
>
>
>
>
> Best Wishes!!
> Vijayendra Gaur


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