Distance transform: Gwyddion Library Reference Manual

Distance transform

Distance transform — Distance transform and related morphological operations

Functions

const GwyEnum *	gwy_distance_transform_type_get_enum ()
void	gwy_nield_distance_transform ()
void	gwy_nield_shrink ()
void	gwy_nield_grow ()
void	gwy_nield_thin ()

Types and Values

enum	GwyDistanceTransformType

Includes

#include <libgwyddion/gwyddion.h>

Description

Functions

gwy_distance_transform_type_get_enum()

const GwyEnum *
gwy_distance_transform_type_get_enum (void);

Returns GwyEnum for GwyDistanceTransformType enum type.

Returns

NULL-terminated GwyEnum which must not be modified nor freed.

gwy_nield_distance_transform()

void
gwy_nield_distance_transform (GwyNield *nield,
                              GwyField *distances,
                              GwyDistanceTransformType dtype,
                              gboolean from_border);

gwy_nield_shrink()

void
gwy_nield_shrink (GwyNield *nield,
                  gdouble amount,
                  GwyDistanceTransformType dtype,
                  gboolean from_border);

Erodes a number field containing mask by specified amount using a distance measure.

Non-zero pixels in nield will be replaced with zeros if they are not farther than amount from the grain boundary as defined by dtype .

Parameters

nield	A number field with zeros in empty space and nonzeros in grains.
amount	How much the grains should be reduced, in pixels. It is inclusive, i.e. pixels that are `amount` far from the border will be removed.
dtype	Type of simple distance to use.
from_border	`TRUE` to consider image edges to be grain boundaries. `FALSE` to reduce grains touching field boundaries only along the boundaries.

gwy_nield_grow()

void
gwy_nield_grow (GwyNield *nield,
                gdouble amount,
                GwyDistanceTransformType dtype,
                gboolean prevent_merging);

Dilates a number field containing mask by specified amount using a distance measure.

Non-positive pixels in field will be replaced with ones if they are not farther than amount from the grain boundary as defined by dtype .

Parameters

nield	A number field with zeros in empty space and nonzeros in grains.
amount	How much the grains should be expanded, in pixels. It is inclusive, i.e. exterior pixels that are `amount` far from the border will be filled.
dtype	Type of simple distance to use.
prevent_merging	`TRUE` to prevent grain merging, i.e. the growth stops where two grains would merge. `FALSE` to simply expand the grains, without regard to grain connectivity.

gwy_nield_thin()

void
gwy_nield_thin (GwyNield *nield);

Performs thinning of a data field containing mask.

The result of thinning is a ‘skeleton’ mask consisting of single-pixel thin lines.

Parameters

field

A data field with zeros in empty space and nonzeros in grains.

Types and Values

enum GwyDistanceTransformType

Type of distance transform.

Members

GWY_DISTANCE_TRANSFORM_CITYBLOCK	City-block distance (sum of horizontal and vertical distances).
GWY_DISTANCE_TRANSFORM_CONN4	Four-connectivity distance; another name for city-block distance.
GWY_DISTANCE_TRANSFORM_CHESS	Chessboard distance (maximum of horizontal and vertical distance).
GWY_DISTANCE_TRANSFORM_CONN8	Eight-connectivity distance; another name for chessboard distance.
GWY_DISTANCE_TRANSFORM_OCTAGONAL48	Octagonal distance beginning from city-block.
GWY_DISTANCE_TRANSFORM_OCTAGONAL84	Octagonal distance beginning from chess.
GWY_DISTANCE_TRANSFORM_OCTAGONAL	Average octagonal distance, i.e. the mean of the 48 and 84 distances.
GWY_DISTANCE_TRANSFORM_EUCLIDEAN	True Euclidean distance.