magni.imaging.dictionaries._visualisations module

Module providing functionality for visualising dictionary coefficients.

Routine listings

visualise_DCT(shape)

Function for visualising DCT coefficients.

visualise_DFT(shape)

Function for visualising DFT coefficients.

magni.imaging.dictionaries._visualisations.visualise_DCT(shape)

Return utilities for visualising DCT coefficients.

A handle to a function to transform the coefficients into a ‘displayable’ format is returned along with a tuple of ranges of the axes in the 2D coefficient plane.

Parameters:shape (tuple) – The shape of the 2D DCT being visualised. Returns:

• display_coefficients (Function) – The function used to transform coefficients into a ‘displayable’ format.
• axes_extent (tuple) – The ranges of the axes in the 2D coefficient plane.

Notes

The display_coefficients function takes log10 to the absolute value of the transform cofficient vector given to it as an argument. The returned displayable coefficients is a matrix.

The axes_extent consists of (abcissa_min, abcissa_max, ordinate_min, ordinate_max).

magni.imaging.dictionaries._visualisations.visualise_DFT(shape)

Return utilities for visualising DFT coefficients.

A handle to a function to transform the coefficients into a ‘displayable’ format is returned along with a tuple of ranges of the axes in the 2D coefficient plane.

Parameters:shape (tuple) – The shape of the 2D DFT being visualised. Returns:

• display_coefficients (Function) – The function used to transform coefficients into a ‘displayable’ format.
• axes_extent (tuple) – The ranges of the axes in the 2D coefficient plane.

Notes

The display_coefficients function takes log10 to the absolute value of the transform cofficient vector given to it as an argument. The returned displayable coefficients is a matrix that is flipped up/down and fftshifted.

The axes_extent consists of (abcissa_min, abcissa_max, ordinate_min, ordinate_max).