Mercurial > hg > wm
diff Meerwald/wm_cox_d.1 @ 0:be303a3f5ea8
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author | Peter Meerwald <pmeerw@cosy.sbg.ac.at> |
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date | Sun, 12 Aug 2007 13:14:34 +0200 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/Meerwald/wm_cox_d.1 Sun Aug 12 13:14:34 2007 +0200 @@ -0,0 +1,132 @@ +.\" +.\" wm_cox_d.1 - the *roff document processor man page source +.\" +.TH wm_cox_d 1 "98/07/05" "Watermarking, Version 1.0" +.SH NAME +.B wm_cox_d +\- a program to extract a signature from the DCT coefficients of a watermarked image +.SH SYNOPSIS +.B wm_cox_d +[ +.BI \-a \ number +] +[ +.B \-h +] +[ +.BI \-i \ ifile +] +[ +.BI \-n \ number +] +[ +.BI \-o \ ofile +] +[ +.BI \-q \ number +] +[ +.BI \-v \ number +] +.br +.BI \-s \ sfile +.I file +.SH DESCRIPTION +.B wm_cox_d +is a program to extract a signature from the DCT coefficients of the watermarked image +.I file. +The +.B cmp_cox_sig +program is used to test the extracted signature against the original signature. +The input image is in PGM (portable graymap) format. +.PP +If +.I file +or +.I ofile +is not specified, then standard input or standard output is +used. +.PP +.B gen_cox_sig +is used to generate a signature file, +.B wm_cox_e +embeds the signature into an image. +.PP +Please refer to Ingemar J. Cox's paper "Secure Spread Spectrum +Watermarking for Multimedia", 1995, to get an idea about the algorithm. +.PP +.SH OPTIONS +.TP +.BI \-a \ number +Alpha factor that determines embedding strength of the signature. +Allows to override the setting in the signature file. +.TP +.B \-h +Print a help message. +.TP +.BI \-i \ ifile +The original image. +.TP +.BI \-o \ ofile +Output watermarked image to the specified +.I file +instead of standard output. +.TP +.BI \-q \ number +Set quantization/quality factor. Overrides the setting in the signature +file. +.TP +.BI \-v \ number +Verbosity level. Default value: 0. +.TP +.BI \-s \ sfile +The signature file to embed into the input image. See +.B gen_cox_sig +(1) for a description of the file format. Mandatory parameter. +.IR file +Input image in PGM format to sign (watermark). Default: standard input. +.TP +.I +The watermarked image file in PGM format. +.PP +.SH OUTPUT +The signed (watermarked) image in PGM format is written to standard output +or ,optionally, to +.I ofile. +The embedding process may take some time on large images since the DCT +is performed on the whole image in one step (not block-wise). +.PP +.PP +The output file has the following format: +.TP +.B CXSG +Magic to identify file type. +.TP +.I number +The length of the signature in bits. +.TP +.I number +The alpha factor (embedding strength). +.TP +.I number +The quantization/quality factor. +.TP +.I numbers +The actual normal distributed signature values, one per line. +.PP +.SH AUTHOR +Peter Meerwald. +Email bug reports to pmeerw@cosy.sbg.ac.at. +.SH AVAILABILITY +The most recent released version of +.B wm_cox_d +is always available +at http://www.cosy.sbg.ac.at/~pmeerw/Watermarking or via anonymous ftp from ftp.cosy.sbg.ac.at in the +directory /pub/people/pmeerw/Watermarking. +.SH "SEE ALSO" +.BR gen_cox_sig +(1), +.BR wm_cox_e +(1), +.BR cmp_cox_sig +(1)