hough: Gwyddion Data Processing Library Reference Manual

## hough hough — Hough transform |

## Functions

void | gwy_data_field_hough_line ()
void | gwy_data_field_hough_circle ()
void | gwy_data_field_hough_line_strenghten ()
void | gwy_data_field_hough_circle_strenghten ()
gint | gwy_data_field_get_local_maxima_list ()
gint | gwy_data_field_get_local_minima_list ()
void | gwy_data_field_hough_polar_line_to_datafield ()
void | gwy_data_field_hough_datafield_line_to_polar ()

## Includes

    #include <libprocess/gwyprocess.h>

## Description

## Functions

### gwy_data_field_hough_line ()

    void
    gwy_data_field_hough_line (GwyDataField *dfield,
                               GwyDataField *x_gradient,
                               GwyDataField *y_gradient,
                               GwyDataField *result,
                               gint hwidth,
                               gboolean overlapping);

### gwy_data_field_hough_circle ()

    void
    gwy_data_field_hough_circle (GwyDataField *dfield,
                                 GwyDataField *x_gradient,
                                 GwyDataField *y_gradient,
                                 GwyDataField *result,
                                 gdouble radius);

### gwy_data_field_hough_line_strenghten ()

    void
    gwy_data_field_hough_line_strenghten (GwyDataField *dfield,
                                          GwyDataField *x_gradient,
                                          GwyDataField *y_gradient,
                                          gint hwidth,
                                          gdouble threshold);

### gwy_data_field_hough_circle_strenghten ()

    void
    gwy_data_field_hough_circle_strenghten
                                   (GwyDataField *dfield,
                                    GwyDataField *x_gradient,
                                    GwyDataField *y_gradient,
                                    gdouble radius,
                                    gdouble threshold);

### gwy_data_field_get_local_maxima_list ()

    gint
    gwy_data_field_get_local_maxima_list (GwyDataField *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. |
ydata | Array of `ndata` elements where the rows should be stored. |
zdata | Array of `ndata` elements where the values should be stored. |
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_data_field_get_local_minima_list ()

    gint
    gwy_data_field_get_local_minima_list (GwyDataField *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. |
ydata | Array of `ndata` elements where the rows should be stored. |
zdata | Array of `ndata` elements where the values should be stored. |
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.

Since: 2.59

### gwy_data_field_hough_polar_line_to_datafield ()

    void
    gwy_data_field_hough_polar_line_to_datafield
                                   (GwyDataField *dfield,
                                    gdouble rho,
                                    gdouble theta,
                                    gint *px1,
                                    gint *px2,
                                    gint *py1,
                                    gint *py2);

### gwy_data_field_hough_datafield_line_to_polar ()

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