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1 .\"
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2 .\" wm_cox_e.1 - the *roff document processor man page source
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3 .\"
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4 .TH wm_cox_e 1 "98/07/01" "Watermarking, Version 1.0"
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5 .SH NAME
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6 .B wm_cox_e
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7 \- a program to embed a signature in the DCT coefficients of an image
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8 .SH SYNOPSIS
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9 .B wm_cox_e
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10 [
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11 .BI \-a \ number
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12 ]
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13 [
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14 .B \-h
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15 ]
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16 [
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17 .BI \-o \ ofile
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18 ]
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19 [
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20 .BI \-q \ number
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21 ]
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22 .BI \-s \ sfile
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23 .I file
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24 .SH DESCRIPTION
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25 .B wm_cox_e
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26 is a program to embed a signature (watermark) from
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27 .I sfile
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28 into the DCT coefficients of an image
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29 .I file
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30 and output a signed (watermarked) image
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31 .I ofile.
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32 Both, input and output image,
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33 are in PGM (portable graymap) format.
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34 .PP
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35 If
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36 .I file
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37 or
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38 .I ofile
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39 is not specified, then standard input or standard output is
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40 used. The signature
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41 .I sfile
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42 is a mandatory parameter however.
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43 .PP
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44 .B gen_cox_sig
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45 is used to generate a signature file,
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46 .B wm_cox_d
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47 extracts a signature from a watermarked image and
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48 .B cmp_cox_sig
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49 allows to compare and test an extracted watermark against the original
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50 signature.
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51 .PP
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52 Please refer to Ingemar J. Cox's paper "Secure Spread Spectrum
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53 Watermarking for Multimedia", 1995, to get an idea about the algorithm.
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54 .PP
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55 .SH OPTIONS
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56 .TP
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57 .BI \-a \ number
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58 Alpha factor that determines embedding strength of the signature.
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59 Allows to override the setting in the signature file.
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60 .TP
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61 .B \-h
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62 Print a help message.
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63 .TP
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64 .BI \-o \ ofile
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65 Output watermarked image to the specified
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66 .I file
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67 instead of standard output.
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68 .TP
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69 .BI \-q \ number
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70 Set quantization/quality factor. Overrides the setting in the signature
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71 file.
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72 .TP
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73 .BI \-s \ sfile
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74 The signature file to embed into the input image. See
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75 .B gen_cox_sig
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76 (1) for a description of the file format. Mandatory parameter.
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77 .IR file
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78 Input image in PGM format to sign (watermark). Default: standard input.
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79 .TP
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80 .I file
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81 The input image in PGM format.
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82 .PP
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83 .SH OUTPUT
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84 The signed (watermarked) image in PGM format is written to standard output
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85 or, optionally, to
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86 .I ofile.
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87 The embedding process may take some time on large images since the DCT
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88 is performed on the whole image in one step (not block-wise).
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89 .PP
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90 The
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91 .I n
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92 largest coefficients are pulsed to embed the
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93 .I n
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94 bit watermark.
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95 .PP
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96 .SH AUTHOR
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97 Peter Meerwald. Email bug reports to pmeerw@cosy.sbg.ac.at.
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98 .SH AVAILABILITY
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99 The most recent released version of
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100 .B wm_cox_e
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101 is always available
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102 at http://www.cosy.sbg.ac.at/~pmeerw/Watermarking or via anonymous ftp from ftp.cosy.sbg.ac.at in the
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103 directory /pub/people/pmeerw/Watermarking.
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104 .SH "SEE ALSO"
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105 .BR gen_cox_sig
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106 (1),
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107 .BR wm_cox_d
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108 (1),
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109 .BR cmp_cox_sig
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110 (1)
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