1Pamtooctaveimg User Manual(0)                    Pamtooctaveimg User Manual(0)
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5       " "netpbm documentation"
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NAME

8       pamtooctaveimg - convert a Netpbm image to a GNU Octave image
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SYNOPSIS

12       pamtooctaveimg [netpbmfile]
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DESCRIPTION

16       This program is part of Netpbm(1).
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18       pamtooctaveimg  reads a Netpbm image as input and produces a GNU Octave
19       ⟨http://www.octave.org/⟩  image file as output.
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21       An Octave image file (called "Octave's image format" in Octave documen‐
22       tation)  is  a  particular  kind of Octave data file.  It describes two
23       matrices:
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27       ·      the image itself as a list of indexes into a colormap, and
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29       ·      the corresponding colormap as  a  list  of  {red,  green,  blue}
30              triplets.
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33       An  Octave  data file is an ASCII text file that you use to import data
34       to Octave.
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36       See the
37        Image                        Processing                        chapter
38       ⟨http://www.gnu.org/software/octave/doc/interpreter/Image-
39       Processing.html#Image-Processing⟩    of  the  GNU  Octave  manual   for
40       details.
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42       pamtooctaveimg writes the output Octave image to Standard Output.
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Arguments

46       netpbmfile  is  the  name  of  the file containing the input PNM or PAM
47       image, or - to indicate Standard Input.  If you don't  specify  netpbm‐
48       file,  the  input is from Standard Input.  pamtooctaveimg converts only
49       the first image in the input stream.
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Examples

54          % pamtooctaveimg myimage.ppm > myimage.img
55          % octave
56          > [img,map] = loadimage("myimage.img");
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58          # (At this point, img is an X by Y matrix and map is a 3 by M matrix.)
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60          > imshow(img,map);   # Displays img with colormap map
61          > [r,g,b] = ind2rgb(img,map);
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63          # (r, g, and b are now each X by Y matrices of color levels [0 to 1].)
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65          > [newimg,newmap] = rgb2ind(r,b,g);   # Swap the blue and green channels.
66          > saveimage("newimage.ppm", newimg, "ppm", newmap);  # Save as a PPM file.
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NOTES

71       There is no octavetopam program.  However, GNU Octave's saveimage  com‐
72       mand can save images in PPM format.
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HISTORY

77       pamtooctaveimg was new in Netpbm 10.39 (June 2007).
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SEE ALSO

82       octave(1), pam(1).
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AUTHOR

86       Copyright (C) 2007 Scott Pakin, scott+pbm@pakin.org.
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DOCUMENT SOURCE

89       This  manual  page was generated by the Netpbm tool 'makeman' from HTML
90       source.  The master documentation is at
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92              http://netpbm.sourceforge.net/doc/pamtooctaveimg.html
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94                                 27 June 2007    Pamtooctaveimg User Manual(0)
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