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sconvolve

$ \bigcirc$Name


sconvolve Convolves a signal with a filter




$ \bigcirc$Command Synopsis


sconvolve [-d Decimation] [-i Interpolation] [-r] [-e Edgemode] [-b] [-p EdgeProl] Signal FicConvol ImpulseResponse [EdgeIR ]



-d Decimation : Downsampling rate (default 1)

-i Interpolation : Upsampling rate (default 1)

-r : Convolution with symetric filter

-e Edgemode : Edge processing mode (0/1/2/3, default 0)

-b : Convolution with high pass filter

-p EdgeProl : Extension of output on edges (0/1/2, default 0)

Signal : Input signal (fsignal)

FicConvol : Result of convolution (fsignal)

ImpulseResponse : Impulse response of inner filter (fsignal)

EdgeIR : Impulse reponses of edge and preconditionning filters (fimage)




$ \bigcirc$Function Summary


void sconvolve (Signal , Output , DownRate , UpRate , ReflIR , Band , Edge , Prolong , Ri , Edge_Ri )

Fsignal Signal ;

Fsignal Output ;

int *DownRate ;

int *UpRate ;

int *ReflIR ;

int *Edge ;

int *Band ;

int *Prolong ;

Fsignal Ri ;

Fimage Edge_Ri ;




$ \bigcirc$Description


sconvolve computes the convolution of a fsignal with a discrete filter which is also of fsignal type. The signal can eventually be interpolated or over-sampled (adding M - 1 zero-valued samples betwen each successive samples) before the convolution, and the result can eventually be decimated or sub-sampled (discarding N - 1 samples over N).

Let {xk} and {yk} be the sample values of the input and output signal, and {hk} the impulse response of the filter, then :

yk = $\displaystyle \sum_{{n}}^{}$hNk-Mlxl

Because the signal is of finite size, one has to use special tricks to compute the edge (i.e. the first and last) coefficients. These are the following :

Notice that if n is the size of the input signal, then the size of the output signal is nM/N, unless the -p option is selected.

The coefficients hk of the filter's impulse response are stored in the fsignal type file ImpulseResponse. The coefficients of the filter's impulse response for computing the edge coefficients are stored in the fimage type file EdgeIR.

The sample values of the input signal are read in the fsignal type file Signal, the sample values of the output signal are stored in the file FicConvol.




$ \bigcirc$See Also


biowave1, biowave2, dybiowave2, ibiowave1, ibiowave2, iowave1, iowave2, owave1, owave2.


$ \bigcirc$Version 1.3


Last Modification date : Thu Jan 31 15:09:23 2002


$ \bigcirc$Author


Jean-Pierre D'Ales






next up previous contents index
Next: iridgelet Up: Reference Previous: precond2d   Contents   Index
mw 2004-05-05