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# wscalogram

Scalogram for continuous wavelet transform

## Syntax

SC = wscalogram(TYPEPLOT,COEFS)
SC = wscalogram(TYPEPLOT,COEFS,'PropName1',PropVal1,...)

## Description

SC = wscalogram(TYPEPLOT,COEFS) computes the scalogram SC which represents the percentage of energy for each coefficient. COEFS is the matrix of the continuous wavelet coefficients (see cwt).

The scalogram is obtained by computing:

```S = abs(coefs.*coefs); SC = 100*S./sum(S(:))
```

When TYPEPLOT is equal to 'image', a scaled image of scalogram is displayed. When TYPEPLOT is equal to 'contour', a contour representation of scalogram is displayed. Otherwise, the scalogram is returned without plot representation.

SC = wscalogram(TYPEPLOT,COEFS,'PropName1',PropVal1,...) allows you to modify some properties. The valid choices for PropName are:

 'scales' Scales used for the CWT. 'ydata' Signal used for the CWT. 'xdata' x values corresponding to the signal values. 'power' Positive real value. Default value is zero.

If power > 0, coefficients are first normalized

```coefs(k,:) = coefs(k,:)/(scales(k)^power)
```

and then the scalogram is computed as explained above.

## Examples

```% Compute signal s
t = linspace(-1,1,512);
s = 1-abs(t);

% Plot signal s
figure;
plot(s), axis tight

```

```% Compute coefficients COEFS using cwt
COEFS = cwt(s,1:32,'cgau4');

% Compute and plot the scalogram (image option)
figure;
SC = wscalogram('image',COEFS);

```

```% Compute and plot the scalogram (contour option)
figure;
SC = wscalogram('contour',COEFS);

```