1 /* 2 * This file is part of FFmpeg. 3 * 4 * FFmpeg is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU Lesser General Public 6 * License as published by the Free Software Foundation; either 7 * version 2.1 of the License, or (at your option) any later version. 8 * 9 * FFmpeg is distributed in the hope that it will be useful, 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 12 * Lesser General Public License for more details. 13 * 14 * You should have received a copy of the GNU Lesser General Public 15 * License along with FFmpeg; if not, write to the Free Software 16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 17 */ 18 19 /** 20 * @file 21 * common functions for edge detection 22 */ 23 24 #ifndef AVFILTER_EDGE_COMMON_H 25 #define AVFILTER_EDGE_COMMON_H 26 27 #include "avfilter.h" 28 29 /** 30 * @brief Rounded directions used in av_image_sobel() 31 */ 32 enum AVRoundedDirection { 33 DIRECTION_45UP, 34 DIRECTION_45DOWN, 35 DIRECTION_HORIZONTAL, 36 DIRECTION_VERTICAL, 37 }; 38 39 /** 40 * Simple sobel operator to get rounded gradients 41 * 42 * @param w the width of the image in pixels 43 * @param h the height of the image in pixels 44 * @param dst data pointers to magnitude image 45 * @param dst_linesize linesizes for the magnitude image 46 * @param dir data pointers to direction image 47 * @param dir_linesize linesizes for the direction image 48 * @param src data pointers to source image 49 * @param src_linesize linesizes for the source image 50 */ 51 void ff_sobel(int w, int h, 52 uint16_t *dst, int dst_linesize, 53 int8_t *dir, int dir_linesize, 54 const uint8_t *src, int src_linesize); 55 56 /** 57 * Filters rounded gradients to drop all non-maxima pixels in the magnitude image 58 * Expects gradients generated by av_image_sobel() 59 * Expects zero's in the destination buffer dst 60 * 61 * @param w the width of the image in pixels 62 * @param h the height of the image in pixels 63 * @param dst data pointers to magnitude image 64 * @param dst_linesize linesizes for the magnitude image 65 * @param dir data pointers to direction image 66 * @param dir_linesize linesizes for the direction image 67 * @param src data pointers to source image 68 * @param src_linesize linesizes for the source image 69 */ 70 void ff_non_maximum_suppression(int w, int h, 71 uint8_t *dst, int dst_linesize, 72 const int8_t *dir, int dir_linesize, 73 const uint16_t *src, int src_linesize); 74 75 /** 76 * Filters all pixels in src to keep all pixels > high, 77 * and keep all pixels > low where all surrounding pixels > high 78 * 79 * @param low the low threshold value 80 * @param high the hegh threshold value 81 * @param w the width of the image in pixels 82 * @param h the height of the image in pixels 83 * @param dst data pointers to destination image 84 * @param dst_linesize linesizes for the destination image 85 * @param src data pointers to source image 86 * @param src_linesize linesizes for the source image 87 */ 88 void ff_double_threshold(int low, int high, int w, int h, 89 uint8_t *dst, int dst_linesize, 90 const uint8_t *src, int src_linesize); 91 92 /** 93 * Applies gaussian blur. 94 * 5x5 kernels, sigma = 1.4 95 * 96 * @param w the width of the image in pixels 97 * @param h the height of the image in pixels 98 * @param dst data pointers to destination image 99 * @param dst_linesize linesizes for the destination image 100 * @param src data pointers to source image 101 * @param src_linesize linesizes for the source image 102 */ 103 void ff_gaussian_blur(int w, int h, 104 uint8_t *dst, int dst_linesize, 105 const uint8_t *src, int src_linesize); 106 107 #endif 108