Saving Information to Disk :: Using Wavelet Packets (Wavelet Toolbox)

Wavelet Toolbox

Saving Information to Disk

Using specific file formats, the graphical tools let you save synthesized signals or images, as well as one- or two-dimensional wavelet packet decomposition structures. This feature provides flexibility and allows you to combine command line and graphical interface operations.

Saving Synthesized Signals

You can process a signal in the Wavelet Packet 1-D tool, and then save the processed signal to a MAT-file.

For example, load the example analysis:

FileExample Analysisdb1 - depth: 2 - ent: shannon --> sumsin

and perform a compression or de-noising operation on the original signal. When you close the Wavelet Packet 1-D De-noising or Wavelet Packet 1-D Compression window, update the synthesized signal by clicking Yes in the dialog box.

Then, from the Wavelet Packet 1-D tool, select the FileSaveSynthesized Signal menu option.

A dialog box appears allowing you to select a directory and filename for the MAT-file. For this example, choose the name synthsig.

To load the signal into your workspace, simply type

```
load synthsig
whos
```
Name
Size
Bytes
Class

synthsig
1x1000
8000
double array

valTHR
1x1
8
double array

wname
1x3
6
char array
```
 


 
```

Name	Size	Bytes	Class
`synthsig`	`1x1000`	`8000`	`double array`
`valTHR`	`1x1`	`8`	`double array`
`wname`	`1x3`	`6`	`char array`

The synthesized signal is given by synthsig. In addition, the parameters of the de-noising or compression process are given by the wavelet name (wname) and the global threshold (valTHR).

```
valTHR

valTHR =
    1.9961
```

Saving Synthesized Images

You can process an image in the Wavelet Packet 2-D tool, and then save the processed image to a MAT-file (with extension mat or other).

For example, load the example analysis:

FileExample Analysisdb1 - depth: 1 - ent: shannon --> woman

and perform a compression on the original image. When you close the Wavelet Packet 2-D Compression window, update the synthesized image by clicking Yes in the dialog box that appears.

Then, from the Wavelet 2-D tool, select the FileSaveSynthesized Image menu option.

A dialog box appears allowing you to select a directory and filename for the MAT-file. For this example, choose the name wpsymage.

To load the image into your workspace, simply type

```
load wpsymage
whos
```
Name
Size
Bytes
Class

X
256x256
524288
double array

map
255x3
6120
double array

valTHR
1x1
8
double array

wname
1x3
6
char array
```
 


 
```

Name	Size	Bytes	Class
`X`	`256x256`	`524288`	`double array`
`map`	`255x3`	`6120`	`double array`
`valTHR`	`1x1`	`8`	`double array`
`wname`	`1x3`	`6`	`char array`

The synthesized image is given by X. The variable map contains the associated colormap. In addition, the parameters of the de-noising or compression process are given by the wavelet name (wname) and the global threshold (valTHR).

Saving One-Dimensional Decomposition Structures

The Wavelet Packet 1-D tool lets you save an entire wavelet packet decomposition tree and related data to your disk. The toolbox creates a MAT-file in the current directory with a name you choose, followed by the extension wp1 (wavelet packet 1-D).

Open the Wavelet Packet 1-D tool and load the example analysis:

FileExample Analysisdb1 - depth: 2 - ent: shannon --> sumsin

To save the data from this analysis, use the menu option FileSave Decomposition.

A dialog box appears that lets you specify a directory and file name for storing the decomposition data. Type the name wpdecex1d.

After saving the decomposition data to the file wpdecex1d.wp1, load the variables into your workspace.

```
load wpdecex1d.wp1 -mat
whos 
```

Name
Size
Bytes
Class

data_name
1x6
12
char array

tree_struct
1x1
11176
wptree object

valTHR
0x0
0
double array

Name	Size	Bytes	Class
`data_name`	`1x6`	`12`	`char array`
`tree_struct`	`1x1`	`11176`	`wptree object`
`valTHR`	`0x0`	`0`	`double array`

The variable tree_struct contains the wavelet packet tree structure. The variable data_name contains the data name and valTHR contains the global threshold, which is currently empty since the synthesized signal does not exist.

Saving Two-Dimensional Decomposition Structures

The file format, variables, and conventions are exactly the same as in the one-dimensional case except for the extension, which is wp2 (wavelet packet 2-D). The variables saved are the same as with the one-dimensional case, with the addition of the colormap matrix map:

Name
Size
Bytes
Class

data_name
1x5
10
char array

map
255x3
6120
double array

tree_struct
1x1
527400
wptree object

valTHR
1x1
8
double array

Name	Size	Bytes	Class
`data_name`	`1x5`	`10`	`char array`
`map`	`255x3`	`6120`	`double array`
`tree_struct`	`1x1`	`527400`	`wptree object`
`valTHR`	`1x1`	`8`	`double array`

Save options are also available when performing de-noising or compression inside the Wavelet Packet 1-D and Wavelet Packet 2-D tools.

In the Wavelet Packet De-Noising windows, you can save the de-noised signal or image and the decomposition. The same holds true for the Wavelet Packet Compression windows.

This way, you can save directly many different trials from inside the De-Noising and Compression windows without going back to the main Wavelet Packet windows during a fine-tuning process.

Note When saving a synthesized signal (1-D), a synthesized image (2-D) or a decomposition to a MAT-file, the extension of this file is free. The mat extension is not necessary.

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