| Gwyddion Data Processing Library Reference Manual |
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dwt — Discrete Wavelet Transform
GwyDataLine* gwy_dwt_set_coefficients (GwyDataLine *dline, GwyDWTType type); GwyDataLine* gwy_data_line_dwt (GwyDataLine *dline, GwyDataLine *wt_coefs, gint isign, gint minsize); GwyDataField* gwy_data_field_xdwt (GwyDataField *dfield, GwyDataLine *wt_coefs, gint isign, gint minsize); GwyDataField* gwy_data_field_ydwt (GwyDataField *dfield, GwyDataLine *wt_coefs, gint isign, gint minsize); GwyDataField* gwy_data_field_dwt (GwyDataField *dfield, GwyDataLine *wt_coefs, gint isign, gint minsize); GwyDataField* gwy_data_field_dwt_denoise (GwyDataField *dfield, GwyDataLine *wt_coefs, gboolean hard, gdouble multiple_threshold, GwyDWTDenoiseType type); GwyDataField* gwy_data_field_dwt_mark_anisotropy (GwyDataField *dfield, GwyDataField *mask, GwyDataLine *wt_coefs, gdouble ratio, gint lowlimit); GwyDataField* gwy_data_field_dwt_correction (GwyDataField *dfield, GwyDataField *mask, GwyDataLine *wt_coefs);
GwyDataLine* gwy_dwt_set_coefficients (GwyDataLine *dline, GwyDWTType type);
Fills resampled or nely allocated GwyDataLine with wavelet coefficients.
| dline : | dataline where coefficients should be stored (allocated or NULL) |
| type : | wavelet type |
| Returns : | resampled or newly allocated GwyDataLine with wavelet coefficients. |
GwyDataLine* gwy_data_line_dwt (GwyDataLine *dline, GwyDataLine *wt_coefs, gint isign, gint minsize);
Performs steps of the wavelet decomposition while 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).
| dline : | dataline to be transformed |
| wt_coefs : | dataline where wavelet transfor coefficients are stored. |
| isign : | direction of the transform (1)...direct, (-1)...inverse |
| minsize : | size of minimal transform result block |
| Returns : | transformed GwyDataLine. |
GwyDataField* gwy_data_field_xdwt (GwyDataField *dfield, GwyDataLine *wt_coefs, gint isign, gint minsize);
Performs steps of the X-direction image wavelet decomposition while 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).
| dfield : | datafield to be transformed |
| wt_coefs : | dataline where wavelet transfor coefficients are stored. |
| isign : | direction of the transform (1)...direct, (-1)...inverse |
| minsize : | size of minimal transform result block |
| Returns : | transformed GwyDataField. |
GwyDataField* gwy_data_field_ydwt (GwyDataField *dfield, GwyDataLine *wt_coefs, gint isign, gint minsize);
Performs steps of the Y-direction image wavelet decomposition while 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).
| dfield : | datafield to be transformed |
| wt_coefs : | dataline where wavelet transfor coefficients are stored. |
| isign : | direction of the transform (1)...direct, (-1)...inverse |
| minsize : | size of minimal transform result block |
| Returns : | transformed GwyDataField. |
GwyDataField* gwy_data_field_dwt (GwyDataField *dfield, GwyDataLine *wt_coefs, gint isign, gint minsize);
Performs steps of the 2D image wavelet decomposition while 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).
| dfield : | datafield to be transformed (square) |
| wt_coefs : | dataline where wavelet transfor coefficients are stored. |
| isign : | direction of the transform (1)...direct, (-1)...inverse |
| minsize : | size of minimal transform result block |
| Returns : | transformed GwyDataField. |
GwyDataField* gwy_data_field_dwt_denoise (GwyDataField *dfield, GwyDataLine *wt_coefs, gboolean hard, gdouble multiple_threshold, GwyDWTDenoiseType type);
Performs wavelet denoising base on threshold obtained from noise variance (obtained from high scale wvelet coefficients). This threshold can be multiplied by user defined value.
| dfield : | datafield to be transformed (square) |
| wt_coefs : | dataline where wavelet transfor coefficients are stored. |
| hard : | whether to apply hard thresholding |
| multiple_threshold : | multiply it by value different from zero to change threshold |
| type : | type of thresholding |
| Returns : | denoised GwyDataField. |
GwyDataField* gwy_data_field_dwt_mark_anisotropy (GwyDataField *dfield, GwyDataField *mask, GwyDataLine *wt_coefs, gdouble ratio, gint lowlimit);
| dfield : | |
| mask : | |
| wt_coefs : | |
| ratio : | |
| lowlimit : | |
| Returns : |
GwyDataField* gwy_data_field_dwt_correction (GwyDataField *dfield, GwyDataField *mask, GwyDataLine *wt_coefs);
| dfield : | |
| mask : | |
| wt_coefs : | |
| Returns : |
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