# rbiowavf

Reverse biorthogonal spline wavelet filters

## Syntax

``[RF,DF] = rbiowavf(wname)``

## Description

example

````[RF,DF] = rbiowavf(wname)` returns the reconstruction (synthesis) and decomposition (analysis) scaling filters, `RF` and `DF`, respectively, associated with the reverse biorthogonal wavelet specified by `wname`.```

## Examples

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Obtain the reverse biorthogonal reconstruction and decomposition scaling filters for the `'rbio3.1'` wavelet. The `'rbio3.1'` wavelet has three vanishing moments for the decomposition (analysis) wavelet and one vanishing moment for the reconstruction (synthesis) wavelet.

`[RF,DF] = rbiowavf('rbio3.1');`

The reconstruction scaling filter, `RF`, and the decomposition filter, `DF`, are equal to the filters returned by `wfilters` scaled by $\sqrt{2}$.

```[LoD,HiD,LoR,HiR] = wfilters('rbio3.1'); max(abs(sqrt(2)*DF-LoD))```
```ans = 0 ```
`max(abs(sqrt(2)*RF-LoR))`
```ans = 0 ```

## Input Arguments

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Name of reverse biorthogonal wavelet, specified as `'rbioNd.Nr'` where possible values for `Nd` and `Nr` are as follows:

 `Nd = 1` `Nr = 1 , 3 or 5` `Nd = 2` `Nr = 2 , 4 , 6 or 8` `Nd = 3` `Nr = 1 , 3 , 5 , 7 or 9` `Nd = 4` `Nr = 4` `Nd = 5` `Nr = 5` `Nd = 6` `Nr = 8`

`Nd` and `Nr` are the numbers of vanishing moments for the decomposition and reconstruction filters, respectively.

Example: `'rbiowavf3.7'`

## Output Arguments

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Reconstruction filter associated with the reverse biorthogonal wavelet `wname`, returned as a real-valued vector.

Decomposition filter associated with the reverse biorthogonal wavelet `wname`, returned as a real-valued vector.

## Version History

Introduced before R2006a