manual.lyx

包含了多个matlab编程在图像中加入水印的处理代码

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\layout Title

Watermarking Source Code
\layout SubTitle

version 0.4
\layout Author

Peter Meerwald
\layout Address

Dept.
 of Scientific Computing, University of Salzburg
\newline 
Jakob-Haringer-Str.
 2, A-5020 Salzburg, Austria
\newline 

\begin_inset LatexCommand \url{mailto:[e-mail]}

\end_inset 


\newline 

\begin_inset LatexCommand \url{http://www.cosy.sbg.ac.at/~pmeerw/Watermarking}

\end_inset 


\layout Abstract

This package provides source code for some watermarking algorithms in hopefully
 portable C code.
 The programs can be used to study watermarking techniques, perform comparative
 robustness tests and develop new attacks against embedded watermarks.
\layout Abstract

However, the provided programs are by no means suitable for real-world applicati
on (i.e.
 copyright protection) and the code solely serves some educational purpose.
\layout Standard


\begin_inset LatexCommand \tableofcontents{}

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\layout Section

Introduction
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Academic research in the watermarking field has grown dramatically since
 approximately 1995.
 But surprisingly, source code for the proposed watermarking schemes has
 not been made available.
 The reason is most likely the security of many watermarking systems lies
 at least to some extent in the embedding and detection algorithm itself,
 and not in the keys used -- violating the Kerckhoff principle 
\begin_inset LatexCommand \cite{Kerckhoff1883a}

\end_inset 

.
\layout Standard

With the availability of public robustness test for watermarking algorithms,
 StirMark 
\begin_inset LatexCommand \cite{Petitcolas99c, Petitcolas98b, Petitcolas98a}

\end_inset 

, Unzign
\begin_float footnote 
\layout Standard


\begin_inset LatexCommand \url{http://www.altern.org/watermark}

\end_inset 


\end_float 
 and very recently Checkmark
\begin_inset LatexCommand \cite{Pereira01b}

\end_inset 

, the situation begins to improve.
 Now it is possible to measure the performance of watermarking systems.
 
\layout Standard

In order the compare and evaluate new embedding and detection techniques,
 it is also necessary to have some reference implementations of the older,
 now often called classical schemes.
 In this work, we provide some implementations of watermarking schemes,
 some of which can be considered 'classical'.
\layout Standard

It was the goal to capture the main ideas of the proposed algorithms, as
 layed out in the respective papers.
 This is clearly not an easy task as some papers do not disclose all details
 or state which particular parameters were used to obtain the results outlined
 in the communications.
\layout Standard

I am very interested in hearing your comments, complaints and suggestions
 regarding this software.
 Moreover, if you have source code for a watermarking scheme not yet covered
 or some useful utility I would be happy to include your code in this distributi
on.
 Please see the contact information at the top of this document.
\layout Standard

If you use the accompanying code, please cite my thesis:
\layout Quotation

Peter Meerwald, Digital Image Watermarking in the Wavelet Transform Domain,
 Master's Thesis, Department of Scientific Computing, University of Salzburg,
 Austria, January 2001.
\layout Section

Software
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Most of the software provided herein was written by myself, as part of my
 Master thesis.
 Some contributions were made by Vassilis Fotopoulos
\begin_float footnote 
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\begin_inset LatexCommand \url{mailto:[e-mail]}

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\end_float 
.
 The software in the archive is organized in the following sub-directories:
\layout Description

Fotopoulos/ contains contributions by Vassilis Fotopoulos
\layout Description

Meerwald/ contains my work
\layout Description

images/ contains the Lena image in PGM format; the default parameters of
 most algorithms are tuned to work best with that image
\layout Description

linux_bin/ the place where the Linux executables are stored in the binary
 distribution
\layout Description

win32_bin/ the place where Windows 32-bit executables are distributed; tested
 with Windows NT 4.0 only
\layout Description

make/ contains the 
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Makefile
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\size default 
 options to build the code on supported platforms
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For the purpose of this software package, a watermarking system comprises
 four parts, namely: signature generation, watermark embedding, watermark
 extraction and signature comparison or detection -- with the exception
 of Vassilis's code; there are only cast and test programs (corresponds
 to watermark embedding and detection).
 Signature is used more less as a synonym for mark and can be thought of
 as the payload (at least for some schemes :-).
\layout Standard

All programs only accept the image in NetPBM format and will also produce
 only NetPBM-format files (see section 
\begin_inset LatexCommand \ref{sec:prereq}

\end_inset 

).
 Unfortunately, most programs have only been tested with 8-bit gray-scale
 images of size 
\begin_inset Formula \( 512\times 512. \)
\end_inset 

 
\layout Standard

In order to simplify batch testing, the programs allow to read either from
 a file, e.g.
\layout Standard


\family typewriter 
\size small 
wm_cox_e -s cox.sig 
\series bold 
image.pgm
\layout Standard

or from standard input, i.e.
\layout Standard

wm_cox_e -s cox.sig 
\series bold 
< image.pgm
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The output is usually written to standard output, i.e.
 
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\family typewriter 
\size small 
wm_cox_e -s cox.sig image.pgm 
\series bold 
> wm_image.pgm
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unless redirected to a file, e.g.
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\family typewriter 
\size small 
wm_cox_e -s cox.sig 
\series bold 
-o wm_image.pgm
\series default 
 image.pgm
\layout Subsection

Featured algorithms
\layout Standard

Currently it includes the following watermarking algorithms
\layout Itemize

Bruyndonckx [bruyn], refer to
\layout Quotation

O.
 Bruyndonckx, Jean-Jacques Quisquater, and Benoit M.
 Macq.
 Spatial method for copyright labeling of digital images.
 In IEEE Workshop on Nonlinear Signal and Image Processing '95, Thessaloniki,
 Greece, pages 456 - 459, 1995.
\layout Itemize

Corvi, refer to
\layout Quotation

Marco Corvi and Gianluca Nicchiotti.
 Wavelet-based image watermarking for copyright protection.
 In Scandinavian Conference on Image Analysis SCIA '97, Lappeenranta, Finland,
 June 1997.
\layout Itemize

Cox, refer to
\layout Quotation

Ingemar J.
 Cox, Joe Kilian, Tom Leighton, and Talal G.
 Shamoon.
 Secure spread spectrum watermarking for multimedia.
 In Proceedings of the IEEE ICIP '97, volume 6, pages 1673 - 1687, Santa
 Barbara, California, USA, 1997.
\layout Itemize

Dugad, refer to
\layout Quotation

Rakesh Dugad, Krishna Ratakonda, and Narendra Ahuja.
 A new wavelet-based scheme for watermarking images.
 In Proceedings of the IEEE International Conference on Image Processing,
 ICIP '98, Chicago, IL, USA, October 1998.
 
\layout Itemize

Fridrich (2.
 scheme), refer to
\layout Quotation

Jiri Fridrich.
 Combining low-frequency and spread spectrum watermarking.
 In Proceedings of the SPIE Symposium on Optical Science, Engineering and
 Instrumentation, San Diego, USA, July 1998.
 
\layout Itemize

Kim, refer to 
\layout Quotation

Jong Ryul Kim and Young Shik Moon.
 A robust wavelet-based digital watermark using level-adaptive thresholding.
 In Proceedings of the 6th IEEE International Conference on Image Processing
 ICIP '99, page 202, Kobe, Japan, October 1999.
\layout Itemize

Koch, refer to
\layout Quotation

Eckhard Koch and Jian Zhao.
 Towards robust and hidden image copyright labeling.
 In Proceedings of the IEEE International Workshop on Nonlinear Signal and
 Image Processing, pages 452 - 455, Halkidiki, Marmaras, Greece, June 1995.
\layout Itemize

Wang, refer to
\layout Quotation

Houng-Jyh Wang, Po-Chyi Su, and C.-C.
 Jay Kuo.
 Wavelet-based digital image watermarking.
 Optics Express, volume 3, pp.
 497, December 1998.
 
\layout Itemize

Xia, refer to
\layout Quotation

Xiang-Gen Xia, Charles G.
 Boncelet, and Gonzalo R.
 Arce.
 Wavelet transform based watermark for digital images.
 Optics Express, volume 3, pp.
 497, December 1998.
\layout Itemize

Xie, refer to
\layout Quotation

Liehua Xie and Gonzalo R.
 Arce.
 Joint wavelet compression and authentication watermarking.
 In Proceedings of the IEEE International Conference on Image Processing,
 ICIP '98, Chicago, IL, USA, 1998.
\layout Itemize

Zhu, refer to
\layout Quotation

Wenwu Zhu, Zixiang Xiong, and Ya-Qin Zhang.
 Multiresolution watermarking for images and video: a unified approach.
 In Proceedings of the IEEE International Conference on Image Processing,
 ICIP '98, Chicago, IL, USA, October 1998.
 
\layout Itemize

Piva/Fotopoulos [cast|test-pv,hart,sub], contribution by Vassilis Fotopoulos,
 refer to
\layout Quotation

M.Barni, F.
 Bartolini, V.
 Cappellini, A.
 Piva.
 A DCT-Domain System for Robust Image Watermarking, Signal Processing, vol.
 66, pp 357 - 372, 1998.
\begin_deeper 
\layout Standard
\added_space_top smallskip \added_space_bottom smallskip 
and
\end_deeper 
\layout Quotation

V.
 Fotopoulos, A.
 N.
 Skodras, A Subband DCT approach to image watermarking, X European Signal
 Processing Conference, September 4 - 8, 2000, Tampere, Finland.
\layout Standard

More algorithms will be added over time, I have implemented about 13 watermarkin
g algorithms in the spatial-, DCT-, and wavelet domain so far.
\layout Subsection


\begin_inset LatexCommand \label{sec:utility_programs}

\end_inset 

Utility programs
\layout Standard

A good way to check the effect of a watermarking algorithm is computing
 the difference image, i.e.
 subtracting the original image from the watermarked image.
 Alternatively, one can also have a look at the modified coefficients in
 the transform domain.
 The following programs facilitate these tasks:
\layout Description

cmp_pgm compute difference image, PSNR, ...
\layout Description

cmp_dct compute full-frame DCT domain difference image
\layout Description

cmp_dct8x8 compute 8x8 block-based DCT difference image
\layout Description

cmp_dwt compute DWT domain difference image
\layout Standard

For example, to produce the difference image of two PGM files and compute
 the PSNR along with some other measures, the following command can be used:
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\family typewriter 
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cmp_pgm -p -i original.pgm -o diff.pgm watermarked.pgm
\layout Section

Usage
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Note, almost all programs will output usage information if called with the
 
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\size small 
-h
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\size default 
 argument.
\layout Subsection

Generating a mark
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First, you have to generate an appropriate signature file for the corresponding
 embedding/detection algorithm; e.g.
 if you are going to use Cox' scheme, then you would run
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\size small 
gen_cox_sig
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The programs outputs some parameters and a sequence of Gaussian distributed
 random numbers (which is the watermark sequence).
 You want to save that into a signature file, so you run
\layout Standard


\family typewriter 
\size small