Hough transform: Gwyddion Library Reference Manual

Hough transform

Hough transform — Hough transform

Functions

void	gwy_field_hough_line ()
void	gwy_field_hough_circle ()
void	gwy_field_hough_line_strenghten ()
void	gwy_field_hough_circle_strenghten ()
gint	gwy_field_get_local_maxima_list ()
gint	gwy_field_get_local_minima_list ()
void	gwy_field_hough_polar_line_to_field ()
void	gwy_field_hough_field_line_to_polar ()

Includes

#include <libgwyddion/gwyddion.h>

Description

Functions

gwy_field_hough_line()

void
gwy_field_hough_line (GwyField *dfield,
                      GwyField *x_gradient,
                      GwyField *y_gradient,
                      GwyField *result,
                      gint hwidth,
                      gboolean overlapping);

gwy_field_hough_circle()

void
gwy_field_hough_circle (GwyField *dfield,
                        GwyField *x_gradient,
                        GwyField *y_gradient,
                        GwyField *result,
                        gdouble radius);

gwy_field_hough_line_strenghten()

void
gwy_field_hough_line_strenghten (GwyField *dfield,
                                 GwyField *x_gradient,
                                 GwyField *y_gradient,
                                 gint hwidth,
                                 gdouble threshold);

gwy_field_hough_circle_strenghten()

void
gwy_field_hough_circle_strenghten (GwyField *dfield,
                                   GwyField *x_gradient,
                                   GwyField *y_gradient,
                                   gdouble radius,
                                   gdouble threshold);

gwy_field_get_local_maxima_list()

gint
gwy_field_get_local_maxima_list (GwyField *dfield,
                                 gdouble *xdata,
                                 gdouble *ydata,
                                 gdouble *zdata,
                                 gint ndata,
                                 gint skip,
                                 gdouble threshold,
                                 gboolean subpixel);

Locates local maxima in a data field.

At most ndata maxima are located (with the largest values).

Parameters

dfield	A two-dimensional data field.
xdata	Array of `ndata` elements where the columns should be stored.	[array length=ndata]
ydata	Array of `ndata` elements where the rows should be stored.	[array length=ndata]
zdata	Array of `ndata` elements where the values should be stored.	[array length=ndata]
ndata	Number of items in `xdata` , `ydata` and `zdata` .
skip	Minimum pixel distance between maxima.
threshold	Minimum value to be considered a maximum.
subpixel	`TRUE` for subpixel refinement.

Returns

The actual number of maxima found.

gwy_field_get_local_minima_list()

gint
gwy_field_get_local_minima_list (GwyField *dfield,
                                 gdouble *xdata,
                                 gdouble *ydata,
                                 gdouble *zdata,
                                 gint ndata,
                                 gint skip,
                                 gdouble threshold,
                                 gboolean subpixel);

Locates local minima in a data field.

At most ndata minima are located (with the smallest values).

Parameters

dfield	A two-dimensional data field.
xdata	Array of `ndata` elements where the columns should be stored.	[array length=ndata]
ydata	Array of `ndata` elements where the rows should be stored.	[array length=ndata]
zdata	Array of `ndata` elements where the values should be stored.	[array length=ndata]
ndata	Number of items in `xdata` , `ydata` and `zdata` .
skip	Minimum pixel distance between minima.
threshold	Maximum value to be considered a minimum.
subpixel	`TRUE` for subpixel refinement.

Returns

The actual number of minima found.

gwy_field_hough_polar_line_to_field()

void
gwy_field_hough_polar_line_to_field (GwyField *dfield,
                                     gdouble rho,
                                     gdouble theta,
                                     gint *px1,
                                     gint *px2,
                                     gint *py1,
                                     gint *py2);

gwy_field_hough_field_line_to_polar()

void
gwy_field_hough_field_line_to_polar (gint px1,
                                     gint px2,
                                     gint py1,
                                     gint py2,
                                     gdouble *rho,
                                     gdouble *theta);