[77] | 1 | /* |
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| 2 | Copyright (C) 2006 Pedro Felzenszwalb |
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| 3 | |
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| 4 | This program is free software; you can redistribute it and/or modify |
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| 5 | it under the terms of the GNU General Public License as published by |
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| 6 | the Free Software Foundation; either version 2 of the License, or |
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| 7 | (at your option) any later version. |
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| 8 | |
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| 9 | This program is distributed in the hope that it will be useful, |
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| 10 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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| 12 | GNU General Public License for more details. |
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| 13 | |
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| 14 | You should have received a copy of the GNU General Public License |
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| 15 | along with this program; if not, write to the Free Software |
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| 16 | Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
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| 17 | */ |
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| 18 | |
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| 19 | /* simple filters */ |
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| 20 | |
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| 21 | #ifndef FILTER_H |
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| 22 | #define FILTER_H |
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| 23 | |
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| 24 | #include <vector> |
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| 25 | #include <cmath> |
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| 26 | #include "image.h" |
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| 27 | #include "misc.h" |
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| 28 | #include "convolve.h" |
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| 29 | #include "imconv.h" |
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| 30 | |
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| 31 | #define WIDTH 4.0 |
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| 32 | |
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| 33 | /* normalize mask so it integrates to one */ |
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| 34 | static void normalize(std::vector<float> &mask) { |
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| 35 | int len = mask.size(); |
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| 36 | float sum = 0; |
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| 37 | for (int i = 1; i < len; i++) { |
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| 38 | sum += fabs(mask[i]); |
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| 39 | } |
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| 40 | sum = 2*sum + fabs(mask[0]); |
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| 41 | for (int i = 0; i < len; i++) { |
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| 42 | mask[i] /= sum; |
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| 43 | } |
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| 44 | } |
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| 45 | |
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| 46 | /* make filters */ |
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| 47 | #define MAKE_FILTER(name, fun) \ |
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| 48 | static std::vector<float> make_ ## name (float sigma) { \ |
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| 49 | sigma = std::max(sigma, 0.01F); \ |
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| 50 | int len = (int)ceil(sigma * WIDTH) + 1; \ |
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| 51 | std::vector<float> mask(len); \ |
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| 52 | for (int i = 0; i < len; i++) { \ |
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| 53 | mask[i] = fun; \ |
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| 54 | } \ |
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| 55 | return mask; \ |
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| 56 | } |
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| 57 | |
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| 58 | MAKE_FILTER(fgauss, exp(-0.5*square(i/sigma))); |
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| 59 | |
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| 60 | /* convolve image with gaussian filter */ |
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| 61 | static imagef *smooth(imagef *src, float sigma) { |
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| 62 | std::vector<float> mask = make_fgauss(sigma); |
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| 63 | normalize(mask); |
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| 64 | |
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| 65 | imagef *tmp = imagef_construct(src->h, src->w, false);//new image<float>(src->height(), src->width(), false); |
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| 66 | imagef *dst = imagef_construct(src->w,src->h,false); //new image<float>(src->width(), src->height(), false); |
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| 67 | convolve_even(src, tmp, mask); |
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| 68 | convolve_even(tmp, dst, mask); |
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| 69 | |
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| 70 | delete tmp; |
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| 71 | return dst; |
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| 72 | } |
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| 73 | |
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| 74 | /* convolve image with gaussian filter */ |
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| 75 | /* |
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| 76 | image<float> *smooth(image<uchar> *src, float sigma) { |
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| 77 | image<float> *tmp = imageUCHARtoFLOAT(src); |
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| 78 | image<float> *dst = smooth(tmp, sigma); |
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| 79 | delete tmp; |
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| 80 | return dst; |
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| 81 | } |
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| 82 | */ |
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| 83 | |
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| 84 | #endif |
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