| /* |
| Copyright (C) 2006 Pedro Felzenszwalb |
| |
| This program is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2 of the License, or |
| (at your option) any later version. |
| |
| This program is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| GNU General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with this program; if not, write to the Free Software |
| Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
| */ |
| |
| /* simple filters */ |
| |
| #ifndef FILTER_H |
| #define FILTER_H |
| |
| #include <algorithm> |
| #include <cmath> |
| #include <vector> |
| #include "third_party/segment/image.h" |
| #include "third_party/segment/misc.h" |
| #include "third_party/segment/convolve.h" |
| #include "third_party/segment/imconv.h" |
| |
| #define WIDTH 4.0 |
| |
| /* normalize mask so it integrates to one */ |
| static void normalize(std::vector<float> *mask) { |
| int len = mask->size(); |
| float sum = 0; |
| for (int i = 1; i < len; i++) { |
| sum += (float)fabs((*mask)[i]); |
| } |
| sum = 2 * sum + (float)fabs((*mask)[0]); |
| for (int i = 0; i < len; i++) { |
| (*mask)[i] /= sum; |
| } |
| } |
| |
| /* make filters */ |
| #define MAKE_FILTER(name, fun) \ |
| static std::vector<float> make_##name(float sigma) { \ |
| sigma = std::max(sigma, 0.01F); \ |
| int len = (int)ceil(sigma * WIDTH) + 1; \ |
| std::vector<float> mask(len); \ |
| for (int i = 0; i < len; i++) { \ |
| mask[i] = fun; \ |
| } \ |
| return mask; \ |
| } |
| |
| MAKE_FILTER(fgauss, (float)exp(-0.5 * square(i / sigma))); |
| |
| /* convolve image with gaussian filter */ |
| static image<float> *smooth(image<float> *src, float sigma) { |
| std::vector<float> mask = make_fgauss(sigma); |
| normalize(&mask); |
| |
| image<float> *tmp = new image<float>(src->height(), src->width(), false); |
| image<float> *dst = new image<float>(src->width(), src->height(), false); |
| convolve_even(src, tmp, mask); |
| convolve_even(tmp, dst, mask); |
| |
| delete tmp; |
| return dst; |
| } |
| |
| /* convolve image with gaussian filter */ |
| image<float> *smooth(image<uchar> *src, float sigma) { |
| image<float> *tmp = imageUCHARtoFLOAT(src); |
| image<float> *dst = smooth(tmp, sigma); |
| delete tmp; |
| return dst; |
| } |
| |
| #endif |