dwt: Gwyddion Data Processing Library Reference Manual

## dwt dwt — Discrete Wavelet Transform |

## Functions

GwyDataLine * | gwy_dwt_set_coefficients ()
void | gwy_data_line_dwt ()
void | gwy_data_field_xdwt ()
void | gwy_data_field_ydwt ()
void | gwy_data_field_dwt ()
void | gwy_data_field_dwt_mark_anisotropy ()

## Includes

    #include <libprocess/gwyprocess.h>

## Description

## Functions

### gwy_dwt_set_coefficients ()

    GwyDataLine *
    gwy_dwt_set_coefficients (GwyDataLine *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). |
type | Wavelet type. |

#### Returns

resampled or newly allocated GwyDataLine with wavelet coefficients.

### gwy_data_line_dwt ()

    void
    gwy_data_line_dwt (GwyDataLine *dline,
                       GwyDataLine *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_data_field_xdwt ()

    void
    gwy_data_field_xdwt (GwyDataField *dfield,
                         GwyDataLine *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` = `dfield->xres` /2 to perform one step of decomposition or `minsize` = 4 to perform full decomposition (or anything between).

#### Parameters

dfield | 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_data_field_ydwt ()

    void
    gwy_data_field_ydwt (GwyDataField *dfield,
                         GwyDataLine *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` = `dfield->yres` /2 to perform one step of decomposition or `minsize` = 4 to perform full decomposition (or anything between).

#### Parameters

dfield | 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_data_field_dwt ()

    void
    gwy_data_field_dwt (GwyDataField *dfield,
                        GwyDataLine *wt_coefs,
                        GwyTransformDirection direction,
                        gint minsize);

Performs steps of the 2D image wavelet decomposition.

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

#### Parameters

dfield | 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_data_field_dwt_mark_anisotropy ()

    void
    gwy_data_field_dwt_mark_anisotropy (GwyDataField *dfield,
                                        GwyDataField *mask,
                                        GwyDataLine *wt_coefs,
                                        gdouble ratio,
                                        gint lowlimit);

Performs steps of the 2D image wavelet decomposition.

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

#### Parameters

dfield | Data field to mark anisotropy of (must be square). |
wt_coefs | Data line to store wavelet transform coefficients to. |
minsize | size of minimal transform result block |