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vf_edgedetect.c File Reference

Edge detection filter. More...

#include "libavutil/opt.h"
#include "avfilter.h"
#include "formats.h"
#include "internal.h"
#include "video.h"

Go to the source code of this file.

Data Structures

struct  EdgeDetectContext
 

Macros

#define OFFSET(x)   offsetof(EdgeDetectContext, x)
 
#define FLAGS   AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
 
#define COPY_MAXIMA(ay, ax, by, bx)
 

Enumerations

enum  { DIRECTION_45UP, DIRECTION_45DOWN, DIRECTION_HORIZONTAL, DIRECTION_VERTICAL }
 

Functions

 AVFILTER_DEFINE_CLASS (edgedetect)
 
static av_cold int init (AVFilterContext *ctx, const char *args)
 
static int query_formats (AVFilterContext *ctx)
 
static int config_props (AVFilterLink *inlink)
 
static void gaussian_blur (AVFilterContext *ctx, int w, int h, uint8_t *dst, int dst_linesize, const uint8_t *src, int src_linesize)
 
static int get_rounded_direction (int gx, int gy)
 
static void sobel (AVFilterContext *ctx, int w, int h, uint16_t *dst, int dst_linesize, const uint8_t *src, int src_linesize)
 
static void non_maximum_suppression (AVFilterContext *ctx, int w, int h, uint8_t *dst, int dst_linesize, const uint16_t *src, int src_linesize)
 
static void double_threshold (AVFilterContext *ctx, int w, int h, uint8_t *dst, int dst_linesize, const uint8_t *src, int src_linesize)
 
static int filter_frame (AVFilterLink *inlink, AVFilterBufferRef *in)
 
static av_cold void uninit (AVFilterContext *ctx)
 

Variables

static const AVOption edgedetect_options []
 
static const AVFilterPad edgedetect_inputs []
 
static const AVFilterPad edgedetect_outputs []
 
AVFilter avfilter_vf_edgedetect
 

Detailed Description

Edge detection filter.

See Also
https://en.wikipedia.org/wiki/Canny_edge_detector

Definition in file vf_edgedetect.c.

Macro Definition Documentation

#define OFFSET (   x)    offsetof(EdgeDetectContext, x)

Definition at line 43 of file vf_edgedetect.c.

Definition at line 44 of file vf_edgedetect.c.

#define COPY_MAXIMA (   ay,
  ax,
  by,
  bx 
)
Value:
do { \
if (src[i] > src[(ay)*src_linesize + i+(ax)] && \
src[i] > src[(by)*src_linesize + i+(bx)]) \
dst[i] = av_clip_uint8(src[i]); \
} while (0)

Referenced by non_maximum_suppression().

Enumeration Type Documentation

anonymous enum
Enumerator:
DIRECTION_45UP 
DIRECTION_45DOWN 
DIRECTION_HORIZONTAL 
DIRECTION_VERTICAL 

Definition at line 130 of file vf_edgedetect.c.

Function Documentation

AVFILTER_DEFINE_CLASS ( edgedetect  )
static av_cold int init ( AVFilterContext ctx,
const char *  args 
)
static

Definition at line 53 of file vf_edgedetect.c.

static int query_formats ( AVFilterContext ctx)
static

Definition at line 69 of file vf_edgedetect.c.

static int config_props ( AVFilterLink inlink)
static

Definition at line 76 of file vf_edgedetect.c.

static void gaussian_blur ( AVFilterContext ctx,
int  w,
int  h,
uint8_t dst,
int  dst_linesize,
const uint8_t src,
int  src_linesize 
)
static

Definition at line 89 of file vf_edgedetect.c.

Referenced by filter_frame().

static int get_rounded_direction ( int  gx,
int  gy 
)
static

Definition at line 137 of file vf_edgedetect.c.

Referenced by sobel().

static void sobel ( AVFilterContext ctx,
int  w,
int  h,
uint16_t *  dst,
int  dst_linesize,
const uint8_t src,
int  src_linesize 
)
static

Definition at line 164 of file vf_edgedetect.c.

Referenced by filter_frame().

static void non_maximum_suppression ( AVFilterContext ctx,
int  w,
int  h,
uint8_t dst,
int  dst_linesize,
const uint16_t *  src,
int  src_linesize 
)
static

Definition at line 190 of file vf_edgedetect.c.

Referenced by filter_frame().

static void double_threshold ( AVFilterContext ctx,
int  w,
int  h,
uint8_t dst,
int  dst_linesize,
const uint8_t src,
int  src_linesize 
)
static

Definition at line 217 of file vf_edgedetect.c.

Referenced by filter_frame().

static int filter_frame ( AVFilterLink inlink,
AVFilterBufferRef in 
)
static

Definition at line 252 of file vf_edgedetect.c.

static av_cold void uninit ( AVFilterContext ctx)
static

Definition at line 294 of file vf_edgedetect.c.

Variable Documentation

const AVOption edgedetect_options[]
static
Initial value:
= {
{ "high", "set high threshold", OFFSET(high), AV_OPT_TYPE_DOUBLE, {.dbl=50/255.}, 0, 1, FLAGS },
{ "low", "set low threshold", OFFSET(low), AV_OPT_TYPE_DOUBLE, {.dbl=20/255.}, 0, 1, FLAGS },
{ NULL },
}

Definition at line 45 of file vf_edgedetect.c.

const AVFilterPad edgedetect_inputs[]
static
Initial value:
= {
{
.name = "default",
.config_props = config_props,
.filter_frame = filter_frame,
.min_perms = AV_PERM_READ,
},
{ NULL }
}

Definition at line 302 of file vf_edgedetect.c.

const AVFilterPad edgedetect_outputs[]
static
Initial value:
= {
{
.name = "default",
},
{ NULL }
}

Definition at line 313 of file vf_edgedetect.c.

AVFilter avfilter_vf_edgedetect
Initial value:
= {
.name = "edgedetect",
.description = NULL_IF_CONFIG_SMALL("Detect and draw edge."),
.priv_size = sizeof(EdgeDetectContext),
.init = init,
.priv_class = &edgedetect_class,
}

Definition at line 321 of file vf_edgedetect.c.