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/*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file
* common functions for edge detection
*/
#ifndef AVFILTER_EDGE_COMMON_H
#define AVFILTER_EDGE_COMMON_H
#include "avfilter.h"
/**
* @brief Rounded directions used in av_image_sobel()
*/
enum AVRoundedDirection {
DIRECTION_45UP,
DIRECTION_45DOWN,
DIRECTION_HORIZONTAL,
DIRECTION_VERTICAL,
};
/**
* Simple sobel operator to get rounded gradients
*
* @param w the width of the image in pixels
* @param h the height of the image in pixels
* @param dst data pointers to magnitude image
* @param dst_linesize linesizes for the magnitude image
* @param dir data pointers to direction image
* @param dir_linesize linesizes for the direction image
* @param src data pointers to source image
* @param src_linesize linesizes for the source image
*/
void ff_sobel(int w, int h,
uint16_t *dst, int dst_linesize,
int8_t *dir, int dir_linesize,
const uint8_t *src, int src_linesize);
/**
* Filters rounded gradients to drop all non-maxima pixels in the magnitude image
* Expects gradients generated by av_image_sobel()
* Expects zero's in the destination buffer dst
*
* @param w the width of the image in pixels
* @param h the height of the image in pixels
* @param dst data pointers to magnitude image
* @param dst_linesize linesizes for the magnitude image
* @param dir data pointers to direction image
* @param dir_linesize linesizes for the direction image
* @param src data pointers to source image
* @param src_linesize linesizes for the source image
*/
void ff_non_maximum_suppression(int w, int h,
uint8_t *dst, int dst_linesize,
const int8_t *dir, int dir_linesize,
const uint16_t *src, int src_linesize);
/**
* Filters all pixels in src to keep all pixels > high,
* and keep all pixels > low where all surrounding pixels > high
*
* @param low the low threshold value
* @param high the hegh threshold value
* @param w the width of the image in pixels
* @param h the height of the image in pixels
* @param dst data pointers to destination image
* @param dst_linesize linesizes for the destination image
* @param src data pointers to source image
* @param src_linesize linesizes for the source image
*/
void ff_double_threshold(int low, int high, int w, int h,
uint8_t *dst, int dst_linesize,
const uint8_t *src, int src_linesize);
/**
* Applies gaussian blur.
* 5x5 kernels, sigma = 1.4
*
* @param w the width of the image in pixels
* @param h the height of the image in pixels
* @param dst data pointers to destination image
* @param dst_linesize linesizes for the destination image
* @param src data pointers to source image
* @param src_linesize linesizes for the source image
*/
void ff_gaussian_blur(int w, int h,
uint8_t *dst, int dst_linesize,
const uint8_t *src, int src_linesize);
#endif
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