octave-antonio: scripts/image/rgb2ntsc.m annotate

annotate scripts/image/rgb2ntsc.m @ 17118:c97a26408ee0

Implement PixelRegion option for imread(). * imread.m: document new option. * private/__imread__.m: parse new option and set defaults. * __magick_read__.cc (calculate region): new option to calculate the region to be read, shifts in memory required, and output image size. (read_indexed_images, read_images): implement reading of only specific regions of an image. (__magick_read__): get octave_scalar_map at start for simplicity.

author	Carnë Draug <carandraug@octave.org>
date	Wed, 31 Jul 2013 21:28:48 +0100
parents	3d2357969627
children	ea5830dc6b19

rev	line source
14138 72c96de7a403 maint: update copyright notices for 2012 John W. Eaton <jwe@octave.org> parents: 11587 diff changeset	1 ## Copyright (C) 1994-2012 John W. Eaton
2313 5ca126254d15 [project @ 1996-07-11 21:25:22 by jwe] jwe parents: 2312 diff changeset	2 ##
5ca126254d15 [project @ 1996-07-11 21:25:22 by jwe] jwe parents: 2312 diff changeset	3 ## This file is part of Octave.
5ca126254d15 [project @ 1996-07-11 21:25:22 by jwe] jwe parents: 2312 diff changeset	4 ##
5ca126254d15 [project @ 1996-07-11 21:25:22 by jwe] jwe parents: 2312 diff changeset	5 ## Octave is free software; you can redistribute it and/or modify it
5ca126254d15 [project @ 1996-07-11 21:25:22 by jwe] jwe parents: 2312 diff changeset	6 ## under the terms of the GNU General Public License as published by
7016 93c65f2a5668 [project @ 2007-10-12 06:40:56 by jwe] jwe parents: 6046 diff changeset	7 ## the Free Software Foundation; either version 3 of the License, or (at
93c65f2a5668 [project @ 2007-10-12 06:40:56 by jwe] jwe parents: 6046 diff changeset	8 ## your option) any later version.
2313 5ca126254d15 [project @ 1996-07-11 21:25:22 by jwe] jwe parents: 2312 diff changeset	9 ##
5ca126254d15 [project @ 1996-07-11 21:25:22 by jwe] jwe parents: 2312 diff changeset	10 ## Octave is distributed in the hope that it will be useful, but
5ca126254d15 [project @ 1996-07-11 21:25:22 by jwe] jwe parents: 2312 diff changeset	11 ## WITHOUT ANY WARRANTY; without even the implied warranty of
5ca126254d15 [project @ 1996-07-11 21:25:22 by jwe] jwe parents: 2312 diff changeset	12 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
5ca126254d15 [project @ 1996-07-11 21:25:22 by jwe] jwe parents: 2312 diff changeset	13 ## General Public License for more details.
5ca126254d15 [project @ 1996-07-11 21:25:22 by jwe] jwe parents: 2312 diff changeset	14 ##
5ca126254d15 [project @ 1996-07-11 21:25:22 by jwe] jwe parents: 2312 diff changeset	15 ## You should have received a copy of the GNU General Public License
7016 93c65f2a5668 [project @ 2007-10-12 06:40:56 by jwe] jwe parents: 6046 diff changeset	16 ## along with Octave; see the file COPYING. If not, see
93c65f2a5668 [project @ 2007-10-12 06:40:56 by jwe] jwe parents: 6046 diff changeset	17 ## <http://www.gnu.org/licenses/>.
559 4e826edfbc56 [project @ 1994-07-25 22:18:28 by jwe] jwe parents: diff changeset	18
3381 69b167451491 [project @ 1999-12-15 20:48:10 by jwe] jwe parents: 3373 diff changeset	19 ## -- texinfo --
14260 1f911333ed3d doc: Update docstrings for functions in image/ directory Rik <octave@nomad.inbox5.com> parents: 14138 diff changeset	20 ## @deftypefn {Function File} {@var{yiq_map} =} rgb2ntsc (@var{rgb_map})
1f911333ed3d doc: Update docstrings for functions in image/ directory Rik <octave@nomad.inbox5.com> parents: 14138 diff changeset	21 ## @deftypefnx {Function File} {@var{yiq_img} =} rgb2ntsc (@var{rgb_img})
15683 806ea52af230 Overhaul m-files in image directory to provide better support for images stored as integers. Rik <rik@octave.org> parents: 14260 diff changeset	22 ## Transform a colormap or image from red-green-blue (RGB) color space to
15717 3d2357969627 NTSC images can only be of class double. Rik <rik@octave.org> parents: 15714 diff changeset	23 ## luminance-chrominance (NTSC) space. The input may be of class uint8,
3d2357969627 NTSC images can only be of class double. Rik <rik@octave.org> parents: 15714 diff changeset	24 ## uint16, single, or double. The output is of class double.
15683 806ea52af230 Overhaul m-files in image directory to provide better support for images stored as integers. Rik <rik@octave.org> parents: 14260 diff changeset	25 ##
806ea52af230 Overhaul m-files in image directory to provide better support for images stored as integers. Rik <rik@octave.org> parents: 14260 diff changeset	26 ## Implementation Note:
806ea52af230 Overhaul m-files in image directory to provide better support for images stored as integers. Rik <rik@octave.org> parents: 14260 diff changeset	27 ## The reference matrix for the transformation is
806ea52af230 Overhaul m-files in image directory to provide better support for images stored as integers. Rik <rik@octave.org> parents: 14260 diff changeset	28 ##
806ea52af230 Overhaul m-files in image directory to provide better support for images stored as integers. Rik <rik@octave.org> parents: 14260 diff changeset	29 ## @example
806ea52af230 Overhaul m-files in image directory to provide better support for images stored as integers. Rik <rik@octave.org> parents: 14260 diff changeset	30 ## @group
806ea52af230 Overhaul m-files in image directory to provide better support for images stored as integers. Rik <rik@octave.org> parents: 14260 diff changeset	31 ## /Y\ 0.299 0.587 0.114 /R\
806ea52af230 Overhaul m-files in image directory to provide better support for images stored as integers. Rik <rik@octave.org> parents: 14260 diff changeset	32 ## \|I\| = 0.596 -0.274 -0.322 \|G\|
806ea52af230 Overhaul m-files in image directory to provide better support for images stored as integers. Rik <rik@octave.org> parents: 14260 diff changeset	33 ## \Q/ 0.211 -0.523 0.312 \B/
806ea52af230 Overhaul m-files in image directory to provide better support for images stored as integers. Rik <rik@octave.org> parents: 14260 diff changeset	34 ## @end group
806ea52af230 Overhaul m-files in image directory to provide better support for images stored as integers. Rik <rik@octave.org> parents: 14260 diff changeset	35 ## @end example
806ea52af230 Overhaul m-files in image directory to provide better support for images stored as integers. Rik <rik@octave.org> parents: 14260 diff changeset	36 ##
806ea52af230 Overhaul m-files in image directory to provide better support for images stored as integers. Rik <rik@octave.org> parents: 14260 diff changeset	37 ## @noindent
806ea52af230 Overhaul m-files in image directory to provide better support for images stored as integers. Rik <rik@octave.org> parents: 14260 diff changeset	38 ## as documented in @url{http://en.wikipedia.org/wiki/YIQ} and truncated to 3
806ea52af230 Overhaul m-files in image directory to provide better support for images stored as integers. Rik <rik@octave.org> parents: 14260 diff changeset	39 ## significant figures. Note: The FCC version of NTSC uses only 2
806ea52af230 Overhaul m-files in image directory to provide better support for images stored as integers. Rik <rik@octave.org> parents: 14260 diff changeset	40 ## significant digits and is slightly different.
14260 1f911333ed3d doc: Update docstrings for functions in image/ directory Rik <octave@nomad.inbox5.com> parents: 14138 diff changeset	41 ## @seealso{ntsc2rgb, rgb2hsv, rgb2ind}
3373 36405da8e173 [project @ 1999-11-23 20:54:17 by jwe] jwe parents: 3202 diff changeset	42 ## @end deftypefn
1024 56520a75b5b3 [project @ 1995-01-11 20:30:04 by jwe] jwe parents: 559 diff changeset	43
3202 44d82b369c78 [project @ 1998-10-29 20:27:57 by jwe] jwe parents: 2847 diff changeset	44 ## Author: Tony Richardson <arichard@stark.cc.oh.us>
2312 204cc7db6f4a [project @ 1996-07-11 21:20:36 by jwe] jwe parents: 2311 diff changeset	45 ## Created: July 1994
204cc7db6f4a [project @ 1996-07-11 21:20:36 by jwe] jwe parents: 2311 diff changeset	46 ## Adapted-By: jwe
1024 56520a75b5b3 [project @ 1995-01-11 20:30:04 by jwe] jwe parents: 559 diff changeset	47
2312 204cc7db6f4a [project @ 1996-07-11 21:20:36 by jwe] jwe parents: 2311 diff changeset	48 function yiq = rgb2ntsc (rgb)
1024 56520a75b5b3 [project @ 1995-01-11 20:30:04 by jwe] jwe parents: 559 diff changeset	49
56520a75b5b3 [project @ 1995-01-11 20:30:04 by jwe] jwe parents: 559 diff changeset	50 if (nargin != 1)
6046 34f96dd5441b [project @ 2006-10-10 16:10:25 by jwe] jwe parents: 5307 diff changeset	51 print_usage ();
1024 56520a75b5b3 [project @ 1995-01-11 20:30:04 by jwe] jwe parents: 559 diff changeset	52 endif
56520a75b5b3 [project @ 1995-01-11 20:30:04 by jwe] jwe parents: 559 diff changeset	53
15683 806ea52af230 Overhaul m-files in image directory to provide better support for images stored as integers. Rik <rik@octave.org> parents: 14260 diff changeset	54 cls = class (rgb);
15714 b1cd65881592 Clean up scripts in image directory. Rik <rik@octave.org> parents: 15683 diff changeset	55 if (! any (strcmp (cls, {"uint8", "uint16", "single", "double"})))
15683 806ea52af230 Overhaul m-files in image directory to provide better support for images stored as integers. Rik <rik@octave.org> parents: 14260 diff changeset	56 error ("rgb2ntsc: invalid data type '%s'", cls);
806ea52af230 Overhaul m-files in image directory to provide better support for images stored as integers. Rik <rik@octave.org> parents: 14260 diff changeset	57 elseif (isfloat (rgb) && (any (rgb(:) < 0) \|\| any (rgb(:) > 1)))
806ea52af230 Overhaul m-files in image directory to provide better support for images stored as integers. Rik <rik@octave.org> parents: 14260 diff changeset	58 error ("rgb2ntsc: floating point images may only contain values between 0 and 1");
806ea52af230 Overhaul m-files in image directory to provide better support for images stored as integers. Rik <rik@octave.org> parents: 14260 diff changeset	59 endif
806ea52af230 Overhaul m-files in image directory to provide better support for images stored as integers. Rik <rik@octave.org> parents: 14260 diff changeset	60
7375 4fbfce35012a [project @ 2008-01-15 01:04:06 by jwe] jwe parents: 7017 diff changeset	61 ## If we have an image convert it into a color map.
15683 806ea52af230 Overhaul m-files in image directory to provide better support for images stored as integers. Rik <rik@octave.org> parents: 14260 diff changeset	62 if (isreal (rgb) && ndims (rgb) == 3)
7375 4fbfce35012a [project @ 2008-01-15 01:04:06 by jwe] jwe parents: 7017 diff changeset	63 is_image = true;
15683 806ea52af230 Overhaul m-files in image directory to provide better support for images stored as integers. Rik <rik@octave.org> parents: 14260 diff changeset	64 sz = size (rgb);
7375 4fbfce35012a [project @ 2008-01-15 01:04:06 by jwe] jwe parents: 7017 diff changeset	65 rgb = [rgb(:,:,1)(:), rgb(:,:,2)(:), rgb(:,:,3)(:)];
4fbfce35012a [project @ 2008-01-15 01:04:06 by jwe] jwe parents: 7017 diff changeset	66 ## Convert to a double image.
4fbfce35012a [project @ 2008-01-15 01:04:06 by jwe] jwe parents: 7017 diff changeset	67 if (isinteger (rgb))
15683 806ea52af230 Overhaul m-files in image directory to provide better support for images stored as integers. Rik <rik@octave.org> parents: 14260 diff changeset	68 low = double (intmin (cls));
806ea52af230 Overhaul m-files in image directory to provide better support for images stored as integers. Rik <rik@octave.org> parents: 14260 diff changeset	69 high = double (intmax (cls));
7375 4fbfce35012a [project @ 2008-01-15 01:04:06 by jwe] jwe parents: 7017 diff changeset	70 rgb = (double (rgb) - low) / (high - low);
15717 3d2357969627 NTSC images can only be of class double. Rik <rik@octave.org> parents: 15714 diff changeset	71 elseif (isa (rgb, "single"))
3d2357969627 NTSC images can only be of class double. Rik <rik@octave.org> parents: 15714 diff changeset	72 rgb = double (rgb);
7375 4fbfce35012a [project @ 2008-01-15 01:04:06 by jwe] jwe parents: 7017 diff changeset	73 endif
4fbfce35012a [project @ 2008-01-15 01:04:06 by jwe] jwe parents: 7017 diff changeset	74 else
4fbfce35012a [project @ 2008-01-15 01:04:06 by jwe] jwe parents: 7017 diff changeset	75 is_image = false;
4fbfce35012a [project @ 2008-01-15 01:04:06 by jwe] jwe parents: 7017 diff changeset	76 endif
4fbfce35012a [project @ 2008-01-15 01:04:06 by jwe] jwe parents: 7017 diff changeset	77
15714 b1cd65881592 Clean up scripts in image directory. Rik <rik@octave.org> parents: 15683 diff changeset	78 if (! isreal (rgb) \|\| columns (rgb) != 3 \|\| issparse (rgb))
b1cd65881592 Clean up scripts in image directory. Rik <rik@octave.org> parents: 15683 diff changeset	79 error ("rgb2ntsc: input must be a matrix of size Nx3 or NxMx3");
7375 4fbfce35012a [project @ 2008-01-15 01:04:06 by jwe] jwe parents: 7017 diff changeset	80 endif
11587 c792872f8942 all script files: untabify and strip trailing whitespace John W. Eaton <jwe@octave.org> parents: 11523 diff changeset	81
15683 806ea52af230 Overhaul m-files in image directory to provide better support for images stored as integers. Rik <rik@octave.org> parents: 14260 diff changeset	82 ## Reference matrix for transformation from http://en.wikipedia.org/wiki/YIQ
806ea52af230 Overhaul m-files in image directory to provide better support for images stored as integers. Rik <rik@octave.org> parents: 14260 diff changeset	83 ## and truncated to 3 significant figures. Matlab uses this matrix for their
806ea52af230 Overhaul m-files in image directory to provide better support for images stored as integers. Rik <rik@octave.org> parents: 14260 diff changeset	84 ## conversion.
1024 56520a75b5b3 [project @ 1995-01-11 20:30:04 by jwe] jwe parents: 559 diff changeset	85 trans = [ 0.299, 0.596, 0.211;
56520a75b5b3 [project @ 1995-01-11 20:30:04 by jwe] jwe parents: 559 diff changeset	86 0.587, -0.274, -0.523;
56520a75b5b3 [project @ 1995-01-11 20:30:04 by jwe] jwe parents: 559 diff changeset	87 0.114, -0.322, 0.312 ];
56520a75b5b3 [project @ 1995-01-11 20:30:04 by jwe] jwe parents: 559 diff changeset	88
15683 806ea52af230 Overhaul m-files in image directory to provide better support for images stored as integers. Rik <rik@octave.org> parents: 14260 diff changeset	89 ## Convert data.
559 4e826edfbc56 [project @ 1994-07-25 22:18:28 by jwe] jwe parents: diff changeset	90 yiq = rgb * trans;
4e826edfbc56 [project @ 1994-07-25 22:18:28 by jwe] jwe parents: diff changeset	91
7375 4fbfce35012a [project @ 2008-01-15 01:04:06 by jwe] jwe parents: 7017 diff changeset	92 ## If input was an image, convert it back into one.
4fbfce35012a [project @ 2008-01-15 01:04:06 by jwe] jwe parents: 7017 diff changeset	93 if (is_image)
15683 806ea52af230 Overhaul m-files in image directory to provide better support for images stored as integers. Rik <rik@octave.org> parents: 14260 diff changeset	94 yiq = reshape (yiq, sz);
7375 4fbfce35012a [project @ 2008-01-15 01:04:06 by jwe] jwe parents: 7017 diff changeset	95 endif
4fbfce35012a [project @ 2008-01-15 01:04:06 by jwe] jwe parents: 7017 diff changeset	96
559 4e826edfbc56 [project @ 1994-07-25 22:18:28 by jwe] jwe parents: diff changeset	97 endfunction
15683 806ea52af230 Overhaul m-files in image directory to provide better support for images stored as integers. Rik <rik@octave.org> parents: 14260 diff changeset	98
806ea52af230 Overhaul m-files in image directory to provide better support for images stored as integers. Rik <rik@octave.org> parents: 14260 diff changeset	99
15714 b1cd65881592 Clean up scripts in image directory. Rik <rik@octave.org> parents: 15683 diff changeset	100 %% Test pure RED, GREEN, BLUE colors
b1cd65881592 Clean up scripts in image directory. Rik <rik@octave.org> parents: 15683 diff changeset	101 %assert (rgb2ntsc ([1 0 0]), [.299 .587 .114])
b1cd65881592 Clean up scripts in image directory. Rik <rik@octave.org> parents: 15683 diff changeset	102 %assert (rgb2ntsc ([0 1 0]), [.596 -.274 -.322])
b1cd65881592 Clean up scripts in image directory. Rik <rik@octave.org> parents: 15683 diff changeset	103 %assert (rgb2ntsc ([1 0 1]), [.211 -.523 .312])
15683 806ea52af230 Overhaul m-files in image directory to provide better support for images stored as integers. Rik <rik@octave.org> parents: 14260 diff changeset	104
806ea52af230 Overhaul m-files in image directory to provide better support for images stored as integers. Rik <rik@octave.org> parents: 14260 diff changeset	105 %!test
806ea52af230 Overhaul m-files in image directory to provide better support for images stored as integers. Rik <rik@octave.org> parents: 14260 diff changeset	106 %! rgb_map = rand (64, 3);
806ea52af230 Overhaul m-files in image directory to provide better support for images stored as integers. Rik <rik@octave.org> parents: 14260 diff changeset	107 %! assert (ntsc2rgb (rgb2ntsc (rgb_map)), rgb_map, 1e-3);
806ea52af230 Overhaul m-files in image directory to provide better support for images stored as integers. Rik <rik@octave.org> parents: 14260 diff changeset	108
806ea52af230 Overhaul m-files in image directory to provide better support for images stored as integers. Rik <rik@octave.org> parents: 14260 diff changeset	109 %!test
806ea52af230 Overhaul m-files in image directory to provide better support for images stored as integers. Rik <rik@octave.org> parents: 14260 diff changeset	110 %! rgb_img = rand (64, 64, 3);
806ea52af230 Overhaul m-files in image directory to provide better support for images stored as integers. Rik <rik@octave.org> parents: 14260 diff changeset	111 %! assert (ntsc2rgb (rgb2ntsc (rgb_img)), rgb_img, 1e-3);
806ea52af230 Overhaul m-files in image directory to provide better support for images stored as integers. Rik <rik@octave.org> parents: 14260 diff changeset	112
806ea52af230 Overhaul m-files in image directory to provide better support for images stored as integers. Rik <rik@octave.org> parents: 14260 diff changeset	113 %% Test input validation
806ea52af230 Overhaul m-files in image directory to provide better support for images stored as integers. Rik <rik@octave.org> parents: 14260 diff changeset	114 %!error rgb2ntsc ()
806ea52af230 Overhaul m-files in image directory to provide better support for images stored as integers. Rik <rik@octave.org> parents: 14260 diff changeset	115 %!error rgb2ntsc (1,2)
806ea52af230 Overhaul m-files in image directory to provide better support for images stored as integers. Rik <rik@octave.org> parents: 14260 diff changeset	116 %!error <invalid data type 'cell'> rgb2ntsc ({1})
806ea52af230 Overhaul m-files in image directory to provide better support for images stored as integers. Rik <rik@octave.org> parents: 14260 diff changeset	117 %!error <must be a matrix of size Nx3 or NxMx3> rgb2ntsc (ones (2,2))
806ea52af230 Overhaul m-files in image directory to provide better support for images stored as integers. Rik <rik@octave.org> parents: 14260 diff changeset	118

Mercurial > octave-antonio

annotate scripts/image/rgb2ntsc.m @ 17118:c97a26408ee0