multires.h File Reference

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Functions
void	HSplitSpec (int X, int Y, double **Spec, double **&lSpec, double **&uSpec)
void	HSplitSpecs (int N, double ***Specs, double ***&lSpecs, double ***&uSpecs)
void	VSplitSpec (int X, int Y, double **Spec, double **&lSpec, double **&rSpec)
void	VSplitSpecs (int N, double ***Specs, double ***&lSpecs, double ***&rSpecs)
double	MixSpectrogram (double **Spec, double ***Specs, int Fr, int WID, int wid, bool norm=true, bool normmix=true, int ***cuts=0)
double	MixSpectrogram (int **spl, double **Spec, double ***Specs, int Fr, int WID, int wid, bool norm=true, bool normmix=true)

Detailed Description

• composite spectrogram routines

This unit deals with basis selection from multiresolution Fourier bases set.

A tiling of an area of the T-F plane is represented as a sequence of 0's and 1's, each 0 represents a horizontal split-in-half, each 1 represents a vertical split-in-half. The sequence is made up of three pieces: 1) the first entry giving the direction of primary split; 2) the tiling of the upper or left half after the primary split; and 3) the tiling of the lower or right half.

A composite spectrogram is represented as a tiling and a vector of amplitude (or square amplitude) values, each representing the energy within a tile. If the primary split is horizontal, then the first/second half of the amplitude or power vector represents the the upper/lower half of the composite spectrogram; if the primary splits is vertical, then the first/second half of the amplitude or power vector represents the left/right half of the composite spectrogram.

Further reading: Wen X. and M. Sandler, "Composite spectrogram using multiple fourier transforms," IET Signal Processing, 3(1):51-63, 2009.

Function Documentation

void HSplitSpec	(	int	X,
		int	Y,
		double **	Spec,
		double **&	lSpec,
		double **&	uSpec
	)

function HSplitSpec: split a spectrogram horizontally into lower and upper halves.

In: Spec[X][Y]: spectrogram to split Out: lSpec[X][Y/2], uSpec[X][Y/2]: the two half spectrograms

No return value. Both lSpec and uSpec are allocated anew. The caller is responsible to free these buffers.

void HSplitSpecs	(	int	N,
		double ***	Specs,
		double ***&	lSpecs,
		double ***&	uSpecs
	)

function HSplitSpecs: split a multiresolution spectrogram horizontally into lower and upper halves

A full spectrogram array is given in log2(N)+1 spectrograms, with the base spec of 1*N, 1st octave of 2*(N/2), ..., last octave of N*1. When this array is split into two spectrogram arrays horizontally, the last spec (with the highest time resolution). Each of the two new arrays is given in log2(N) spectrograms.

In: Specs[nRes+1][][]: multiresolution spectrogram Out: lSpecs[nRes][][], uSpecs[nRes][][], the two half multiresolution spectrograms

This function allocates two 2nd order arrays of double*, which the caller is responsible to free.

double MixSpectrogram	(	double **	Spec,
		double ***	Specs,
		int	Fr,
		int	WID,
		int	wid,
		bool	norm,
		bool	normmix,
		int ***	cuts
	)

function MixSpectrogram: obtain composite spectrogram from multiresolutin spectrogram as pixel grid

This method deals with Fr (base) frames of WID samples. Each base frame may be divided into 2 1st- octave frames, 4 2nd-octave frames, ..., etc. The spectrogram calculated on base frame is given in Specs[0] (Fr frames); that of 1st octave is given in Specs[1] (2*Fr frames); etc. The method resamples the spectrograms of different frame width into a single spectrogram so that the entropy is maximized globally.

The output Spec is a spectrogram of apparent resolution WID at hop size wid. It is a redundant representation, with equal values occupying blocks of size WID/wid.

In: Specs[0][Fr][WID], Specs[1][Fr*2][WID/2], ..., Specs[Res-1] [Fr*(WID/wid)][wid], multiresolution spectrogram Out: Spec[Fr*(WID/wid)][WID], composite spectrogram as pixel grid cuts[Fr][wid][N=Wid/wid], tilings of small square blocks Returns 0.

double MixSpectrogram	(	int **	spl,
		double **	Spec,
		double ***	Specs,
		int	Fr,
		int	WID,
		int	wid,
		bool	norm,
		bool	normmix
	)

function MixSpectrogram: obtain composite spectrogram from multiresolutin spectrogram as vectors

In: Specs[0][Fr][WID], Specs[1][Fr*2][WID/2], ..., Specs[Res-1] [Fr*(WID/wid)][wid], multiresolution spectrogram Out: spl[Fr][WID], Spec[Fr][WID], composite spectrogram as tiling and value vectors by frame.

Returns 0.

void VSplitSpec	(	int	X,
		int	Y,
		double **	Spec,
		double **&	lSpec,
		double **&	rSpec
	)

function VSplitSpec: split a spectrogram vertically into left and right halves.

In: Spec[X][Y]: spectrogram to split Out: lSpec[X][Y/2], rSpec[X][Y/2]: the two half spectrograms

No return value. Both lSpec and rSpec are allocated anew. The caller is responsible to free these buffers.

void VSplitSpecs	(	int	N,
		double ***	Specs,
		double ***&	lSpecs,
		double ***&	rSpecs
	)

function VSplitSpecs: split a multiresolution spectrogram vertically into left and right halves

A full spectrogram array is given in log2(N)+1 spectrograms, with the base spec of 1*N, 1st octave of 2*(N/2), ..., last octave of N*1. When this array is split into two spectrogram arrays horizontally, the last spec (with the highest time resolution). Each of the two new arrays is given in log2(N) spectrograms.

In: Specs[nRes+1][][]: multiresolution spectrogram Out: lSpecs[nRes][][], rSpecs[nRes][][], the two half multiresolution spectrograms

This function allocates two 2nd order arrays of double*, which the caller is responsible to free.