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iptcheckconn: implement in C++ as static method for connectivity. * iptcheckconn.m: file removed; help text and tests reused for C++. * conndef.cc: implement two new connectivity::validate() methods and the iptcheckconn function for Octave as caller to those methods. * conndef.h: define the connectivity::validate() static methods. * COPYING
author Carnë Draug <carandraug@octave.org>
date Wed, 01 Oct 2014 20:22:37 +0100
parents 9e4ecfd52273
children
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
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1 ## Copyright (C) 2013 Brandon Miles <brandon.miles7@gmail.com>
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2 ##
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3 ## This program is free software; you can redistribute it and/or modify it
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4 ## under the terms of the GNU General Public License as published by
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5 ## the Free Software Foundation; either version 3 of the License, or
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6 ## (at your option) any later version.
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7 ##
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8 ## This program is distributed in the hope that it will be useful,
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9 ## but WITHOUT ANY WARRANTY; without even the implied warranty of
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10 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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11 ## GNU General Public License for more details.
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12 ##
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13 ## You should have received a copy of the GNU General Public License
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14 ## along with this program. If not, see <http://www.gnu.org/licenses/>.
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15
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16 ## -*- texinfo -*-
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17 ## @deftypefn {Function File} {[@var{gradMag}, @var{gradDir}] =} imgradient (@var{img})
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18 ## @deftypefnx {Function File} {[@var{gradMag}, @var{gradDir}] =} imgradient (@var{img}, @var{method})
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19 ## @deftypefnx {Function File} {[@var{gradMag}, @var{gradDir}] =} imgradient (@var{gx}, @var{gy})
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20 ## Compute the gradient magnitude and direction in degrees for an image.
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21 ##
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22 ## These are computed from the @var{gx} and @var{xy} gradients using
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23 ## @code{imgradientxy}. The first input @var{img} is a gray scale image to
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24 ## compute the edges on. The second input @var{method} controls the method
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25 ## used to calculate the gradients. Alternatively the first input @var{gx}
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26 ## can be the x gradient and the second input @var{gy} can be the y gradient.
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27 ##
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28 ## The first output @var{gradMag} returns the magnitude of the gradient.
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29 ## The second output @var{gradDir} returns the direction in degrees.
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30 ##
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31 ## The @var{method} input argument must be a string specifying one of the
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32 ## methods supported by @code{imgradientxy}.
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33 ##
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34 ## @seealso{edge, imgradientxy}
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35 ## @end deftypefn
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36
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37 function [gradMag, gradDir] = imgradient (img, method = "sobel")
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38
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39 if (nargin < 1 || nargin > 2)
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40 print_usage ();
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41 elseif (ndims (img) != 2)
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42 error("imgradient: IMG must be a 2 dimensional matrix");
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43 endif
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44
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45 if (ischar (method))
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46 [gradX, gradY] = imgradientxy (img, method);
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47 else
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48 ## we already got gX and gY, just confirm it's good data
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49 if (! size_equal (img, method))
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50 error("imgradient: GX and GY must be of equal size")
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51 endif
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52 gradX = img;
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53 gradY = method;
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54 endif
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55
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56 gradMag = sqrt (gradX.^2 + gradY.^2);
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57
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58 if (nargout > 1)
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59 ## Why imgradient invert vertical when computing the angle
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60 ## Use atan2(-gy,gx)*pi/180. See http://stackoverflow.com/questions/18549015
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61 gradDir = atan2d (-gradY, gradX);
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62 endif
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63
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64 endfunction
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65
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66 %!test
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67 %! A = [0 1 0
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68 %! 1 1 1
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69 %! 0 1 0];
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70 %!
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71 %! [gMag, gDir] = imgradient (A);
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72 %! assert (gMag,[sqrt(18) 4 sqrt(18); 4 0 4; sqrt(18),4,sqrt(18)]);
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73 %! assert (gDir,[-45 -90 -135; -0 -0 -180; 45 90 135]);
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74 %!
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75 %! ## the following just test if passing gx and gy separately gets
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76 %! ## us the same as the image and method though imgradient
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77 %! [gxSobel, gySobel] = imgradientxy (A, "Sobel");
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78 %! [gxPrewitt, gyPrewitt] = imgradientxy (A, "Prewitt");
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79 %! [gxCd, gyCd] = imgradientxy (A, "CentralDifference");
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80 %! [gxId, gyId] = imgradientxy (A, "IntermediateDifference");
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81 %!
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82 %! assert (imgradient (A),
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83 %! imgradient (gxSobel, gySobel));
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84 %! assert (imgradient (A, "Sobel"),
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85 %! imgradient (gxSobel, gySobel));
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86 %! assert (imgradient (A, "Prewitt"),
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87 %! imgradient(gxPrewitt, gyPrewitt));
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88 %! assert (imgradient (A, "CentralDifference"),
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89 %! imgradient (gxCd, gyCd));
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90 %! assert (imgradient (A, "IntermediateDifference"),
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91 %! imgradient (gxId, gyId));
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92