DWT: Gwyddion Library Reference Manual

DWT

DWT — Discrete Wavelet Transform

Functions

const GwyEnum *	gwy_dwt_type_get_enum ()
const GwyEnum *	gwy_dwt_denoise_type_get_enum ()
GwyLine *	gwy_dwt_set_coefficients ()
void	gwy_line_dwt ()
void	gwy_field_xdwt ()
void	gwy_field_ydwt ()
void	gwy_field_dwt ()
void	gwy_field_dwt_mark_anisotropy ()
void	gwy_NIELD_dwt_mark_anisotropy ()

Types and Values

enum	GwyDWTType
enum	GwyDWTDenoiseType

Includes

#include <libgwyddion/gwyddion.h>

Description

Functions

gwy_dwt_type_get_enum()

const GwyEnum *
gwy_dwt_type_get_enum (void);

Returns GwyEnum for GwyDWTType enum type.

Returns

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

gwy_dwt_denoise_type_get_enum()

const GwyEnum *
gwy_dwt_denoise_type_get_enum (void);

Returns GwyEnum for GwyDWTDenoiseType enum type.

Returns

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

gwy_dwt_set_coefficients()

GwyLine *
gwy_dwt_set_coefficients (GwyLine *dline,
                          GwyDWTType type);

Fills resampled or nely allocated data line with wavelet coefficients.

Parameters

dline	Data line to store wavelet coefficients to (or `NULL` to allocate a new one).	[nullable]
type	Wavelet type.

Returns

resampled or newly allocated GwyLine with wavelet coefficients.

[transfer none]

gwy_line_dwt()

void
gwy_line_dwt (GwyLine *dline,
              GwyLine *wt_coefs,
              GwyTransformDirection direction,
              gint minsize);

Performs steps of the wavelet decomposition.

The smallest low pass coefficients block is equal to minsize . Run with minsize = dline->res /2 to perform one step of decomposition or minsize = 4 to perform full decomposition (or anything between).

Parameters

dline	Data line to be transformed, it must have at least four samples.
wt_coefs	Data line where the wavelet transform coefficients are stored.
direction	Transform direction.
minsize	size of minimal transform result block

gwy_field_xdwt()

void
gwy_field_xdwt (GwyField *field,
                GwyLine *wt_coefs,
                GwyTransformDirection direction,
                gint minsize);

Performs steps of the X-direction image wavelet decomposition.

The smallest low pass coefficients block is equal to minsize . Run with minsize = field->xres /2 to perform one step of decomposition or minsize = 4 to perform full decomposition (or anything between).

Parameters

field	Data field to be transformed.
wt_coefs	Data line where the wavelet transform coefficients are stored.
direction	Transform direction.
minsize	size of minimal transform result block

gwy_field_ydwt()

void
gwy_field_ydwt (GwyField *field,
                GwyLine *wt_coefs,
                GwyTransformDirection direction,
                gint minsize);

Performs steps of the Y-direction image wavelet decomposition.

The smallest low pass coefficients block is equal to minsize . Run with minsize = field->yres /2 to perform one step of decomposition or minsize = 4 to perform full decomposition (or anything between).

Parameters

field	Data field to be transformed.
wt_coefs	Data line where the wavelet transform coefficients are stored.
direction	Transform direction.
minsize	size of minimal transform result block

gwy_field_dwt()

void
gwy_field_dwt (GwyField *field,
               GwyLine *wt_coefs,
               GwyTransformDirection direction,
               gint minsize);

Performs steps of the 2D image wavelet decomposition.

Parameters

field	Data field to be transformed (must be square).
wt_coefs	Data line where the wavelet transform coefficients are stored.
direction	Transform direction.
minsize	size of minimal transform result block

gwy_field_dwt_mark_anisotropy()

void
gwy_field_dwt_mark_anisotropy (GwyField *field,
                               GwyField *mask,
                               GwyLine *wt_coefs,
                               gdouble ratio,
                               gint lowlimit);

Performs steps of the 2D image wavelet decomposition.

Parameters

field	Data field to mark anisotropy of (must be square).
mask	Output mask field.
wt_coefs	Data line to store wavelet transform coefficients to.
ratio	Anisotropy threshold.
lowlimit	Size of minimal transform result block.

gwy_NIELD_dwt_mark_anisotropy()

void
gwy_NIELD_dwt_mark_anisotropy (GwyField *field,
                               GwyNield *mask,
                               GwyLine *wt_coefs,
                               gdouble ratio,
                               gint lowlimit);

Performs steps of the 2D image wavelet decomposition.

Parameters

field	Data field to mark anisotropy of (must be square).
mask	Number field to fill with the output mask.
wt_coefs	Data line to store wavelet transform coefficients to.
ratio	Anisotropy threshold.
lowlimit	Size of minimal transform result block.

Types and Values

enum GwyDWTType

Members

GWY_DWT_HAAR
GWY_DWT_DAUB4
GWY_DWT_DAUB6
GWY_DWT_DAUB8
GWY_DWT_DAUB12
GWY_DWT_DAUB20

enum GwyDWTDenoiseType

Members

GWY_DWT_DENOISE_UNIVERSAL
GWY_DWT_DENOISE_SCALE_ADAPTIVE
GWY_DWT_DENOISE_SPACE_ADAPTIVE