Color Constancy filter. More...

#include "libavutil/imgutils.h"
#include "libavutil/opt.h"
#include "libavutil/pixdesc.h"
#include "avfilter.h"
#include "formats.h"
#include "internal.h"
#include "video.h"
#include <math.h>

Data Structures
struct	ThreadData
	Used for passing data between threads. More...

struct	ColorConstancyContext
	Common struct for all algorithms contexts. More...

Macros
#define	GREY_EDGE "greyedge"

#define	SQRT3 1.73205080757

#define	NUM_PLANES 3

#define	MAX_DIFF_ORD 2

#define	MAX_META_DATA 4

#define	MAX_DATA 4

#define	INDEX_TEMP 0

#define	INDEX_DX 1

#define	INDEX_DY 2

#define	INDEX_DXY 3

#define	INDEX_NORM INDEX_DX

#define	INDEX_SRC 0

#define	INDEX_DST 1

#define	INDEX_ORD 2

#define	INDEX_DIR 3

#define	DIR_X 0

#define	DIR_Y 1

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

#define	FLAGS AV_OPT_FLAG_FILTERING_PARAM\|AV_OPT_FLAG_VIDEO_PARAM

#define	GINDX(s, i) ( (i) - ((s) >> 2) )

#define	CLAMP(x, mx) av_clip((x), 0, (mx-1))

#define	INDX2D(r, c, w) ( (r) * (w) + (c) )

#define	GAUSS(s, sr, sc, sls, sh, sw, g) ( (s)[ INDX2D(CLAMP((sr), (sh)), CLAMP((sc), (sw)), (sls)) ] * (g) )

Functions
static int	set_gauss (AVFilterContext *ctx)
	Sets gauss filters used for calculating gauss derivatives. More...

static void	cleanup_derivative_buffers (ThreadData *td, int nb_buff, int nb_planes)
	Frees up buffers used by grey edge for storing derivatives final and intermidiate results. More...

static int	setup_derivative_buffers (AVFilterContext ctx, ThreadData td)
	Allocates buffers used by grey edge for storing derivatives final and intermidiate results. More...

static int	slice_get_derivative (AVFilterContext ctx, void arg, int jobnr, int nb_jobs)
	Slice calculation of gaussian derivatives. More...

static int	slice_normalize (AVFilterContext ctx, void arg, int jobnr, int nb_jobs)
	Slice Frobius normalization of gaussian derivatives. More...

static void av_always_inline	get_deriv (AVFilterContext ctx, ThreadData td, int ord, int dir, int src, int dst, int dim, int nb_threads)
	Utility function for setting up differentiation data/metadata. More...

static int	get_derivative (AVFilterContext ctx, ThreadData td)
	Main control function for calculating gaussian derivatives. More...

static int	filter_slice_grey_edge (AVFilterContext ctx, void arg, int jobnr, int nb_jobs)
	Slice function for grey edge algorithm that does partial summing/maximizing of gaussian derivatives. More...

static int	filter_grey_edge (AVFilterContext ctx, AVFrame in)
	Main control function for grey edge algorithm. More...

static void	normalize_light (double *light)
	Normalizes estimated illumination since only illumination vector direction is required for color constancy. More...

static int	illumination_estimation (AVFilterContext ctx, AVFrame in)
	Redirects to corresponding algorithm estimation function and performs normalization after estimation. More...

static int	diagonal_transformation (AVFilterContext ctx, void arg, int jobnr, int nb_jobs)
	Performs simple correction via diagonal transformation model. More...

static void	chromatic_adaptation (AVFilterContext ctx, AVFrame in, AVFrame *out)
	Main control function for correcting scene illumination based on estimated illumination. More...

static int	query_formats (AVFilterContext *ctx)

static int	config_props (AVFilterLink *inlink)

static int	filter_frame (AVFilterLink inlink, AVFrame in)

static av_cold void	uninit (AVFilterContext *ctx)

Variables
static const AVFilterPad	colorconstancy_inputs []

static const AVFilterPad	colorconstancy_outputs []

Detailed Description

Color Constancy filter.

See Also: http://colorconstancy.com/

[J]. van de Weijer, Th. Gevers, A. Gijsenij "Edge-Based Color Constancy".

Definition in file vf_colorconstancy.c.

Macro Definition Documentation

#define GREY_EDGE "greyedge"

Definition at line 42 of file vf_colorconstancy.c.

#define SQRT3 1.73205080757

Definition at line 44 of file vf_colorconstancy.c.

Referenced by diagonal_transformation().

#define NUM_PLANES 3

Definition at line 46 of file vf_colorconstancy.c.

Referenced by cleanup_derivative_buffers(), diagonal_transformation(), filter_grey_edge(), filter_slice_grey_edge(), normalize_light(), setup_derivative_buffers(), slice_get_derivative(), and slice_normalize().

#define MAX_DIFF_ORD 2

Definition at line 47 of file vf_colorconstancy.c.

#define MAX_META_DATA 4

Definition at line 48 of file vf_colorconstancy.c.

#define MAX_DATA 4

Definition at line 49 of file vf_colorconstancy.c.

#define INDEX_TEMP 0

Definition at line 51 of file vf_colorconstancy.c.

Referenced by get_derivative().

#define INDEX_DX 1

Definition at line 52 of file vf_colorconstancy.c.

Referenced by get_derivative(), and slice_normalize().

#define INDEX_DY 2

Definition at line 53 of file vf_colorconstancy.c.

Referenced by get_derivative(), and slice_normalize().

#define INDEX_DXY 3

Definition at line 54 of file vf_colorconstancy.c.

Referenced by get_derivative(), and slice_normalize().

#define INDEX_NORM INDEX_DX

Definition at line 55 of file vf_colorconstancy.c.

Referenced by filter_slice_grey_edge(), get_derivative(), and slice_normalize().

#define INDEX_SRC 0

Definition at line 56 of file vf_colorconstancy.c.

Referenced by get_deriv(), and slice_get_derivative().

#define INDEX_DST 1

Definition at line 57 of file vf_colorconstancy.c.

Referenced by filter_grey_edge(), filter_slice_grey_edge(), get_deriv(), and slice_get_derivative().

#define INDEX_ORD 2

Definition at line 58 of file vf_colorconstancy.c.

Referenced by get_deriv(), and slice_get_derivative().

#define INDEX_DIR 3

Definition at line 59 of file vf_colorconstancy.c.

Referenced by get_deriv(), and slice_get_derivative().

#define DIR_X 0

Definition at line 60 of file vf_colorconstancy.c.

Referenced by get_derivative(), and slice_get_derivative().

#define DIR_Y 1

Definition at line 61 of file vf_colorconstancy.c.

Referenced by get_derivative().

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

Definition at line 92 of file vf_colorconstancy.c.

#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM

Definition at line 93 of file vf_colorconstancy.c.

#define GINDX	(	s,
		i
	)	( (i) - ((s) >> 2) )

Definition at line 95 of file vf_colorconstancy.c.

Referenced by set_gauss(), and slice_get_derivative().

#define CLAMP	(	x,
		mx
	)	av_clip((x), 0, (mx-1))

Definition at line 234 of file vf_colorconstancy.c.

#define INDX2D	(	r,
		c,
		w
	)	( (r) * (w) + (c) )

Definition at line 235 of file vf_colorconstancy.c.

Referenced by filter_slice_grey_edge(), and slice_get_derivative().

#define GAUSS	(	s,
		sr,
		sc,
		sls,
		sh,
		sw,
		g
	)	( (s)[ INDX2D(CLAMP((sr), (sh)), CLAMP((sc), (sw)), (sls)) ] * (g) )

Definition at line 236 of file vf_colorconstancy.c.

Referenced by slice_get_derivative().

Function Documentation

static int set_gauss ( AVFilterContext * ctx )

static

Sets gauss filters used for calculating gauss derivatives.

Filter size depends on sigma which is a user option hence we calculate these filters each time. Also each higher order depends on lower ones. Sigma can be zero only at difford = 0, then we only convert data to double instead.

Parameters

ctx	the filter context.

Returns: 0 in case of success, a negative value corresponding to an AVERROR code in case of failure.

Definition at line 109 of file vf_colorconstancy.c.

Referenced by config_props().

static void cleanup_derivative_buffers	(	ThreadData *	td,
		int	nb_buff,
		int	nb_planes
	)

static

Frees up buffers used by grey edge for storing derivatives final and intermidiate results.

Number of buffers and number of planes for last buffer are given so it can be safely called at allocation failure instances.

Parameters

td	holds the buffers.
nb_buff	number of buffers to be freed.
nb_planes	number of planes for last buffer to be freed.

Definition at line 189 of file vf_colorconstancy.c.

Referenced by filter_grey_edge(), and setup_derivative_buffers().

static int setup_derivative_buffers	(	AVFilterContext *	ctx,
		ThreadData *	td
	)

static

Allocates buffers used by grey edge for storing derivatives final and intermidiate results.

Parameters

ctx	the filter context.
td	holds the buffers.

Returns: 0 in case of success, a negative value corresponding to an AVERROR code in case of failure.

Definition at line 214 of file vf_colorconstancy.c.

Referenced by filter_grey_edge().

static int slice_get_derivative	(	AVFilterContext *	ctx,
		void *	arg,
		int	jobnr,
		int	nb_jobs
	)

static

Slice calculation of gaussian derivatives.

Applies 1-D gaussian derivative filter either horizontally or vertically according to meta data given in thread data. When convoluting horizontally source is always the in frame withing thread data while when convoluting vertically source is a buffer.

Parameters

ctx	the filter context.
arg	data to be passed between threads.
jobnr	current job nubmer.
nb_jobs	total number of jobs.

Returns: 0.

Applying gauss horizontally along each row

Applying gauss vertically along each column

Definition at line 251 of file vf_colorconstancy.c.

Referenced by get_deriv().

static int slice_normalize	(	AVFilterContext *	ctx,
		void *	arg,
		int	jobnr,
		int	nb_jobs
	)

static

Slice Frobius normalization of gaussian derivatives.

Only called for difford values of 1 or 2.

Parameters

ctx	the filter context.
arg	data to be passed between threads.
jobnr	current job nubmer.
nb_jobs	total number of jobs.

Returns: 0.

Definition at line 319 of file vf_colorconstancy.c.

Referenced by filter_grey_edge().

static void av_always_inline get_deriv	(	AVFilterContext *	ctx,
		ThreadData *	td,
		int	ord,
		int	dir,
		int	src,
		int	dst,
		int	dim,
		int	nb_threads
	)

static

Utility function for setting up differentiation data/metadata.

Parameters

ctx	the filter context.
td	to be used for passing data between threads.
ord	ord of differentiation.
dir	direction of differentiation.
src	index of source used for differentiation.
dst	index destination used for saving differentiation result.
dim	maximum dimension in current direction.
nb_threads	number of threads to use.

Definition at line 365 of file vf_colorconstancy.c.

Referenced by get_derivative().

static int get_derivative	(	AVFilterContext *	ctx,
		ThreadData *	td
	)

static

Main control function for calculating gaussian derivatives.

Parameters

ctx	the filter context.
td	holds the buffers used for storing results.

Returns: 0 in case of success, a negative value corresponding to an AVERROR code in case of failure.

Definition at line 383 of file vf_colorconstancy.c.

Referenced by filter_grey_edge().

static int filter_slice_grey_edge	(	AVFilterContext *	ctx,
		void *	arg,
		int	jobnr,
		int	nb_jobs
	)

static

Slice function for grey edge algorithm that does partial summing/maximizing of gaussian derivatives.

Parameters

ctx	the filter context.
arg	data to be passed between threads.
jobnr	current job nubmer.
nb_jobs	total number of jobs.

Returns: 0.

Definition at line 439 of file vf_colorconstancy.c.

Referenced by filter_grey_edge().

static int filter_grey_edge	(	AVFilterContext *	ctx,
		AVFrame *	in
	)

static

Main control function for grey edge algorithm.

Parameters

ctx	the filter context.
in	frame to perfrom grey edge on.

Returns: 0 in case of success, a negative value corresponding to an AVERROR code in case of failure.

Definition at line 488 of file vf_colorconstancy.c.

Referenced by illumination_estimation().

static void normalize_light ( double * light )

static

Normalizes estimated illumination since only illumination vector direction is required for color constancy.

Parameters

light the estimated illumination to be normalized in place

Definition at line 536 of file vf_colorconstancy.c.

Referenced by illumination_estimation().

static int illumination_estimation	(	AVFilterContext *	ctx,
		AVFrame *	in
	)

static

Redirects to corresponding algorithm estimation function and performs normalization after estimation.

Parameters

ctx	the filter context.
in	frame to perfrom estimation on.

Returns: 0 in case of success, a negative value corresponding to an AVERROR code in case of failure.

Definition at line 567 of file vf_colorconstancy.c.

Referenced by filter_frame().

static int diagonal_transformation	(	AVFilterContext *	ctx,
		void *	arg,
		int	jobnr,
		int	nb_jobs
	)

static

Performs simple correction via diagonal transformation model.

Parameters

ctx	the filter context.
arg	data to be passed between threads.
jobnr	current job nubmer.
nb_jobs	total number of jobs.

Returns: 0.

Definition at line 593 of file vf_colorconstancy.c.

Referenced by chromatic_adaptation().

static void chromatic_adaptation	(	AVFilterContext *	ctx,
		AVFrame *	in,
		AVFrame *	out
	)

static

Main control function for correcting scene illumination based on estimated illumination.

Parameters

ctx	the filter context.
in	holds frame to correct
out	holds corrected frame

Definition at line 628 of file vf_colorconstancy.c.

Referenced by filter_frame().

static int query_formats ( AVFilterContext * ctx )

static

Definition at line 639 of file vf_colorconstancy.c.

static int config_props ( AVFilterLink * inlink )

static

Definition at line 651 of file vf_colorconstancy.c.

static int filter_frame	(	AVFilterLink *	inlink,
		AVFrame *	in
	)

static

Definition at line 679 of file vf_colorconstancy.c.

static av_cold void uninit ( AVFilterContext * ctx )

static

Definition at line 706 of file vf_colorconstancy.c.

Variable Documentation

const AVFilterPad colorconstancy_inputs[]

static

Initial value:

= {
    {
        .name         = "default",
        .type         = AVMEDIA_TYPE_VIDEO,
        .config_props = config_props,
        .filter_frame = filter_frame,
    },
    { NULL }
}

Definition at line 717 of file vf_colorconstancy.c.

const AVFilterPad colorconstancy_outputs[]

static

Initial value:

= {
    {
        .name = "default",
        .type = AVMEDIA_TYPE_VIDEO,
    },
    { NULL }
}

Definition at line 727 of file vf_colorconstancy.c.

Data Structures

Macros

Functions

Variables

Detailed Description

Macro Definition Documentation

Function Documentation

Variable Documentation