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annotate scripts/image/ind2gray.m @ 559:4e826edfbc56

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[project @ 1994-07-25 22:18:28 by jwe] Initial revision
author jwe
date Mon, 25 Jul 1994 22:19:05 +0000
parents
children 3470f1e25a79
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4e826edfbc56 [project @ 1994-07-25 22:18:28 by jwe]
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1 function Y = ind2gray(X,map)
4e826edfbc56 [project @ 1994-07-25 22:18:28 by jwe]
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2 #Convert an octave indexed image to a gray scale intensity image.
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3 #
4e826edfbc56 [project @ 1994-07-25 22:18:28 by jwe]
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4 #Y = ind2gray(X) converts an indexed image to a gray scale intensity
4e826edfbc56 [project @ 1994-07-25 22:18:28 by jwe]
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5 #image. The current colormap is used to determine the intensities.
4e826edfbc56 [project @ 1994-07-25 22:18:28 by jwe]
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6 #The intensity values lie between 0 and 1 inclusive.
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7 #
4e826edfbc56 [project @ 1994-07-25 22:18:28 by jwe]
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8 #Y = ind2gray(X,map) uses the specified colormap instead of the current
4e826edfbc56 [project @ 1994-07-25 22:18:28 by jwe]
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9 #one in the conversion process.
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10 #
4e826edfbc56 [project @ 1994-07-25 22:18:28 by jwe]
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11 #SEE ALSO: gray2ind, rgb2ntsc, image, colormap
4e826edfbc56 [project @ 1994-07-25 22:18:28 by jwe]
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12
4e826edfbc56 [project @ 1994-07-25 22:18:28 by jwe]
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13 if (nargin == 1)
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14 map = colormap;
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15 endif
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16
4e826edfbc56 [project @ 1994-07-25 22:18:28 by jwe]
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17 # Convert colormap to intensity values.
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18 yiq = rgb2ntsc(map);
4e826edfbc56 [project @ 1994-07-25 22:18:28 by jwe]
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19 y = yiq(:,1);
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20
4e826edfbc56 [project @ 1994-07-25 22:18:28 by jwe]
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21 # We need Fortran indexing capability, but be sure to save the user's
4e826edfbc56 [project @ 1994-07-25 22:18:28 by jwe]
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22 # preference.
4e826edfbc56 [project @ 1994-07-25 22:18:28 by jwe]
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23 pref = do_fortran_indexing;
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24 do_fortran_indexing = "true";
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25
4e826edfbc56 [project @ 1994-07-25 22:18:28 by jwe]
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26 # Replace indices in the input matrix with indexed values in the output
4e826edfbc56 [project @ 1994-07-25 22:18:28 by jwe]
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27 # matrix.
4e826edfbc56 [project @ 1994-07-25 22:18:28 by jwe]
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28 [rows, cols] = size(X);
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29 Y = y(X(:));
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30 Y = reshape(Y,rows,cols);
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31
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32 # Restore the user's preference.
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33 do_fortran_indexing = pref;
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34
4e826edfbc56 [project @ 1994-07-25 22:18:28 by jwe]
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35 endfunction