Commit 5025bc4e authored by Odd-Arild Kristensen's avatar Odd-Arild Kristensen Committed by Jean-Baptiste Kempf

Implemented a new edge detection video filter

The edge detection filter uses the Sobel operator to detect and highlight
edges in a frame. In order to successfully detect an edge, the image must
first be converted to gray scale (because Sobel is a gray scale operator) and
then have a slight Gaussian blur applied to it. We do this because Sobel is a
noisy operator and the Gaussian blur reduces this noise.
Signed-off-by: Jean-Baptiste Kempf's avatarJean-Baptiste Kempf <jb@videolan.org>
parent 4b983bd7
...@@ -123,6 +123,7 @@ Video filter: ...@@ -123,6 +123,7 @@ Video filter:
* Hardware deinterlacing on the rPI, using MMAL * Hardware deinterlacing on the rPI, using MMAL
* New video filter to convert between fps rates * New video filter to convert between fps rates
* Added 9-bit and 10-bit support to image adjust filter * Added 9-bit and 10-bit support to image adjust filter
* New edge detection filter uses the Sobel operator to detect edges
Stream Output: Stream Output:
* Chromecast output module * Chromecast output module
......
List of vlc plugins (414) List of vlc plugins (475)
$Id$ $Id$
* a52: A/52 basic parser/packetizer * a52: A/52 basic parser/packetizer
* a52tofloat32: A/52 audio converter & decoder plugin, using liba52 * a52tofloat32: A/52 audio converter & decoder plugin, using liba52
...@@ -128,6 +128,7 @@ $Id$ ...@@ -128,6 +128,7 @@ $Id$
* dxa9: Convert D3D9 GPU textures to YUV planes * dxa9: Convert D3D9 GPU textures to YUV planes
* dxva2: DxVA2 hardware-accelerated decoding * dxva2: DxVA2 hardware-accelerated decoding
* dynamicoverlay: subpicture filter using shared memory that can be written to by external applications * dynamicoverlay: subpicture filter using shared memory that can be written to by external applications
* edgedetection: edge detection video filter
* edummy: dummy encoder * edummy: dummy encoder
* egl_android: Android EGL video output * egl_android: Android EGL video output
* egl_win32: Windows EGL video output * egl_win32: Windows EGL video output
......
...@@ -3,6 +3,8 @@ video_filterdir = $(pluginsdir)/video_filter ...@@ -3,6 +3,8 @@ video_filterdir = $(pluginsdir)/video_filter
noinst_HEADERS += video_filter/filter_picture.h noinst_HEADERS += video_filter/filter_picture.h
# video filters # video filters
libedgedetection_plugin_la_SOURCES = video_filter/edgedetection.c
libedgedetection_plugin_la_LIBADD = $(LIBM)
libadjust_plugin_la_SOURCES = video_filter/adjust.c video_filter/adjust_sat_hue.c video_filter/adjust_sat_hue.h libadjust_plugin_la_SOURCES = video_filter/adjust.c video_filter/adjust_sat_hue.c video_filter/adjust_sat_hue.h
libadjust_plugin_la_LIBADD = $(LIBM) libadjust_plugin_la_LIBADD = $(LIBM)
libalphamask_plugin_la_SOURCES = video_filter/alphamask.c libalphamask_plugin_la_SOURCES = video_filter/alphamask.c
...@@ -75,6 +77,7 @@ video_filter_LTLIBRARIES = \ ...@@ -75,6 +77,7 @@ video_filter_LTLIBRARIES = \
libcanvas_plugin.la \ libcanvas_plugin.la \
libcolorthres_plugin.la \ libcolorthres_plugin.la \
libcroppadd_plugin.la \ libcroppadd_plugin.la \
libedgedetection_plugin.la \
liberase_plugin.la \ liberase_plugin.la \
libextract_plugin.la \ libextract_plugin.la \
libgradient_plugin.la \ libgradient_plugin.la \
......
/******************************************************************************
* edgedetection.c : edge detection plugin for VLC
*****************************************************************************
* Copyright (C) 2016 VLC authors and VideoLAN
* $Id$
*
* Authors: Odd-Arild Kristensen <oddarildkristensen@gmail.com>
*
* This program 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.
*
* 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 Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
*****************************************************************************/
/*****************************************************************************
* Preamble
*****************************************************************************/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include <vlc_common.h>
#include <vlc_plugin.h>
#include <vlc_filter.h>
/*****************************************************************************
* Module descriptor
*****************************************************************************/
#define EDGE_DETECTION_DESCRIPTION N_( "Edge detection video filter" )
#define EDGE_DETECTION_TEXT N_( "Edge detection" )
#define EDGE_DETECTION_LONGTEXT N_( \
"Detects edges in the frame and highlights them in white." )
#define WHITE 255
/*****************************************************************************
* Local prototypes
*****************************************************************************/
static int Open( vlc_object_t * );
static int Close( vlc_object_t * );
static picture_t *new_frame( filter_t * );
static picture_t *Filter( filter_t *, picture_t * );
static uint8_t sobel( const uint8_t *, const int, const int, int, int);
/* Kernel for X axis */
static const signed char pi_kernel_x[3][3] = {
{-1, 0, 1},
{-2, 0, 2},
{-1, 0, 1}
};
/* Kernel for Y axis */
static const signed char pi_kernel_y[3][3] = {
{-1, -2, -1},
{0, 0, 0},
{1, 2, 1}
};
vlc_module_begin ()
set_description( EDGE_DETECTION_DESCRIPTION )
set_shortname( EDGE_DETECTION_TEXT )
set_help( EDGE_DETECTION_LONGTEXT )
set_category( CAT_VIDEO )
set_subcategory( SUBCAT_VIDEO_VFILTER )
set_capability( "video filter2", 0 )
set_callbacks( Open, Close )
vlc_module_end ()
/* Store the filter chain */
struct filter_sys_t
{
filter_chain_t *p_chain;
};
/*****************************************************************************
* Opens the filter.
* Allocates and initializes data needed by the filter. The image needs to
* be black-and-white in order to detect any edges. The Gaussian blur is
* needed so that the Sobel operator does not give a high response for noise,
* or small changes in the image.
*****************************************************************************/
static int Open( vlc_object_t *p_this )
{
int i_ret;
es_format_t fmt;
filter_t *p_filter = (filter_t *)p_this;
filter_owner_t owner = {
.sys = p_filter,
.video = {
.buffer_new = new_frame,
},
};
/* Store the filter chain in p_sys */
p_filter->p_sys = (filter_sys_t *)filter_chain_NewVideo( p_filter, true, &owner );
if ( p_filter->p_sys == NULL)
{
msg_Err( p_filter, "Could not allocate filter chain" );
free( p_filter->p_sys );
return VLC_EGENERIC;
}
es_format_Copy( &fmt, &p_filter->fmt_in );
/* Clear filter chain */
filter_chain_Reset( (filter_chain_t *)p_filter->p_sys, &p_filter->fmt_in, &fmt);
/* Add adjust filter to turn frame black-and-white */
i_ret = filter_chain_AppendFromString( (filter_chain_t *)p_filter->p_sys,
"adjust{saturation=0}" );
if ( i_ret == -1 )
{
msg_Err( p_filter, "Could not append filter to filter chain" );
filter_chain_Delete( (filter_chain_t *)p_filter->p_sys );
return VLC_EGENERIC;
}
/* Add gaussian blur to the frame so to remove noise from the frame */
i_ret = filter_chain_AppendFromString( (filter_chain_t *)p_filter->p_sys,
"gaussianblur{deviation=1}" );
if ( i_ret == -1 )
{
msg_Err( p_filter, "Could not append filter to filter chain" );
filter_chain_Delete( (filter_chain_t *)p_filter->p_sys );
return VLC_EGENERIC;
}
/* Set callback function */
p_filter->pf_video_filter = Filter;
return VLC_SUCCESS;
}
/******************************************************************************
* Closes the filter and cleans up all dynamically allocated data.
******************************************************************************/
static int Close( vlc_object_t *p_this )
{
filter_t *p_filter = (filter_t *)p_this;
filter_chain_Delete( (filter_chain_t *)p_filter->p_sys );
return VLC_SUCCESS;
}
/* *****************************************************************************
* Allocates a new buffer for the filter chain.
******************************************************************************/
static picture_t *new_frame( filter_t *p_filter)
{
return filter_NewPicture( p_filter->owner.sys );
}
/******************************************************************************
* Callback function.
* This function implements the sobel operator which can be used to detect
* edges in a black-and-white image. The sobel operator is applied to
* every pixel in the frame for both X and Y axis.
******************************************************************************/
static picture_t *Filter( filter_t *p_filter, picture_t *p_pic )
{
picture_t *p_filtered_frame =
filter_chain_VideoFilter( (filter_chain_t *)p_filter->p_sys, p_pic );
picture_t *p_out_frame = picture_NewFromFormat( &p_pic->format );
if ( p_out_frame == NULL )
{
picture_Release( p_filtered_frame );
msg_Err( p_filter, "Could not allocate memory for new frame" );
return NULL;
}
const int i_lines = p_filtered_frame->p[Y_PLANE].i_visible_lines;
const int i_pitch = p_filtered_frame->p[Y_PLANE].i_pitch;
/* Loop through every pixel in the frame */
for ( int i_line = 0; i_line < i_lines; i_line++ )
{
for ( int i_col = 0; i_col < i_pitch; i_col++ )
{
/* Set the new value for the pixel */
*( p_out_frame->p[Y_PLANE].p_pixels + ((i_pitch * i_line) + i_col) ) =
sobel( p_filtered_frame->p[Y_PLANE].p_pixels,
i_pitch, i_lines, i_col, i_line );
}
}
picture_Release( p_filtered_frame );
return p_out_frame;
}
/******************************************************************************
* Sobel Operator.
* Calculates the gradients for both X and Y directions in a frame.
******************************************************************************/
static uint8_t sobel( const uint8_t *p_pixels, const int i_pitch,
const int i_lines, int i_col, int i_line )
{
int i_x_val = 0;
int i_y_val = 0;
int i_col_offset;
int i_line_offset;
for ( int i_x = 0; i_x < 3; i_x++ )
{
/* Check if we are at the first pixel on the scanline */
if (i_x == 0 && i_col == 0)
{
/* Duplicate the first pixel on the scanline */
i_col_offset = 0;
}
/* Check if we are on the last pixel on the scanline */
else if (i_x == 2 && i_col == i_pitch - 1)
{
/* Duplicate the last pixel on the scanline */
i_col_offset = i_pitch - 1;
}
else
{
i_col_offset = i_col + i_x - 1;
}
for ( int i_y = 0; i_y < 3; i_y++ )
{
/* Check if we are at the top scanline */
if (i_y == 0 && i_line == 0)
{
/* Duplicate the top pixel */
i_line_offset = 0;
}
/* Check if we are the bottom scanline */
else if (i_y == 2 && i_line == i_lines - 1 )
{
/* Duplicate the bottom pixel */
i_line_offset = i_pitch * (i_lines - 1);
}
else {
i_line_offset = i_pitch * (i_line + i_y - 1);
}
/* Apply the kernel to the pixel */
i_x_val += pi_kernel_x[i_x][i_y] * p_pixels[i_line_offset + i_col_offset];
i_y_val += pi_kernel_y[i_x][i_y] * p_pixels[i_line_offset + i_col_offset];
}
}
int i_ret = abs(i_x_val) + abs(i_y_val);
return (i_ret > WHITE) ? WHITE : i_ret;
}
...@@ -1101,6 +1101,7 @@ modules/video_filter/dynamicoverlay/dynamicoverlay_commands.c ...@@ -1101,6 +1101,7 @@ modules/video_filter/dynamicoverlay/dynamicoverlay_commands.c
modules/video_filter/dynamicoverlay/dynamicoverlay.h modules/video_filter/dynamicoverlay/dynamicoverlay.h
modules/video_filter/dynamicoverlay/dynamicoverlay_list.c modules/video_filter/dynamicoverlay/dynamicoverlay_list.c
modules/video_filter/dynamicoverlay/dynamicoverlay_queue.c modules/video_filter/dynamicoverlay/dynamicoverlay_queue.c
modules/video_filter/edgedetection.c
modules/video_filter/erase.c modules/video_filter/erase.c
modules/video_filter/extract.c modules/video_filter/extract.c
modules/video_filter/filter_event_info.h modules/video_filter/filter_event_info.h
......
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