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annotate scripts/image/ind2gray.m @ 904:3470f1e25a79

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[project @ 1994-11-09 21:22:15 by jwe]
author jwe
date Wed, 09 Nov 1994 21:22:15 +0000
parents 4e826edfbc56
children b843a65fa977
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4e826edfbc56 [project @ 1994-07-25 22:18:28 by jwe]
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1 function Y = ind2gray(X,map)
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2
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3 # Convert an octave indexed image to a gray scale intensity image.
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4 #
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5 # Y = ind2gray(X) converts an indexed image to a gray scale intensity
3470f1e25a79 [project @ 1994-11-09 21:22:15 by jwe]
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6 # image. The current colormap is used to determine the intensities.
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7 # The intensity values lie between 0 and 1 inclusive.
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8 #
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9 # Y = ind2gray(X,map) uses the specified colormap instead of the current
3470f1e25a79 [project @ 1994-11-09 21:22:15 by jwe]
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10 # one in the conversion process.
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11 #
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12 # SEE ALSO: gray2ind, rgb2ntsc, image, colormap
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4e826edfbc56 [project @ 1994-07-25 22:18:28 by jwe]
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14 if (nargin == 1)
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15 map = colormap;
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16 endif
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17
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18 # Convert colormap to intensity values.
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19 yiq = rgb2ntsc(map);
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20 y = yiq(:,1);
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21
4e826edfbc56 [project @ 1994-07-25 22:18:28 by jwe]
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22 # 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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23 # preference.
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24 pref = do_fortran_indexing;
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25 do_fortran_indexing = "true";
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4e826edfbc56 [project @ 1994-07-25 22:18:28 by jwe]
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27 # 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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28 # matrix.
4e826edfbc56 [project @ 1994-07-25 22:18:28 by jwe]
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29 [rows, cols] = size(X);
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30 Y = y(X(:));
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31 Y = reshape(Y,rows,cols);
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33 # Restore the user's preference.
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34 do_fortran_indexing = pref;
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36 endfunction