1Pamtooctaveimg User Manual(0)                    Pamtooctaveimg User Manual(0)
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NAME

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

16       pamtooctaveimg [netpbmfile]
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DESCRIPTION

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

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

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

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

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

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

90       Copyright (C) 2007 Scott Pakin, scott+pbm@pakin.org.
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94netpbm documentation          27 June 2007<br /> Pamtooctaveimg User Manual(0)
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