Wavelet Packet Analysis Express VI

Owning Palette: Wavelet Packet VIs

Requires: Advanced Signal Processing Toolkit

Decomposes the signal according to the tree structure you specify and reconstructs the signal from the nodes you specify. This VI also returns the coefficients and the entropies of the nodes you select.

Dialog Box Options

Block Diagram Inputs

Block Diagram Outputs

Dialog Box Options

Parameter	Description
Data Source	Specifies whether this Express VI reads data from a block diagram input terminal or from a file. From terminal specifies that this Express VI reads data from a block diagram input terminal. From file specifies that this Express VI reads data from a file. This Express VI can read data from waveform, WAV, or TXT files.
File Path Configuration	Contains the following options: File path—Specifies and displays the path to the file from which this Express VI reads data. This option is available only when you select From file in the Data Source section. Prompt to choose a file each time this VI runs—Specifies whether this Express VI displays a dialog box that prompts you to select a file each time this Express VI runs. This option is available only when you select the From file option in the Data Source section.
Signals and Coefficients	Displays the following graphs: Original and reconstructed signal—Displays the original and the reconstructed signal. Nodes coefficients—Displays the coefficients of the nodes you select. If you select multiple nodes, this VI concatenates the node coefficients into one array.
Decomposition Settings	Contains the following options: Wavelet—Specifies the wavelet type to use for the discrete wavelet analysis. The default is db02. The options include two types: orthogonal (Haar, Daubechies (dbxx), Coiflets (coifx), Symmlets (symx)) and biorthogonal (Biorthogonal (biorx_x), including FBI (bior4_4 (FBI))), where x indicates the order of the wavelet. The higher the order, the smoother the wavelet. The orthogonal wavelets are not redundant and are suitable for signal or image denoising and compression. The biorthogonal wavelets usually have the linear phase property and are suitable for signal or image feature extraction. Entropy type—Specifies the method to use to compute the entropy of the wavelet packet coefficients. Best tree—Specifies to decompose the signal based on the minimum entropy criterion. Levels—Specifies the number of levels in the discrete wavelet analysis. Levels must be a positive integer no greater than log2(Ls), where Ls is the length of the signal. Optional parameter—Specifies the associated parameter for the Threshold, SURE, and Norm entropy. Optional parameter is not available when you select Shannon or Energy in Entropy type.
Decomposition Tree	Plots the entire tree structure of the wavelet packet tree. Click a node to select it and display the coefficients of the node and the reconstruction of the signal in Signals and Coefficients. <Ctrl>–click to select multiple nodes. Double-click to split or join nodes. Zoom out—Zooms out the decomposition tree. Zoom in—Zooms in the decomposition tree. Restore—Restores the decomposition tree. Display mode—Specifies the display mode of the node strings in the decomposition tree. Contains the following options: node path—Displays the node with a string that consists of the characters 0 and 1, where 0 represents lowpass filtering, and 1 represents highpass filtering. depth, pos—Displays the node with the depth of the node in the tree and the position of the node in its level. The depth and the position start with 0. The depth ascends from the top to the bottom of the tree. The position ascends from the left to the right in a level. entropy—Displays the node with the entropy of the node.

Block Diagram Inputs

Parameter	Description
error in (no error)	Describes error conditions that occur before this node runs.
Signal	Specifies the block diagram terminal of the data you want to load. This input is available only if you select the From terminal option in the Data Source section.
File path	Specifies the file path of the data you want to load. This input is available only when you select the From file option in the Data Source section.

Block Diagram Outputs

Parameter	Description
Reconstruction	Returns the reconstructed signal.
node coeffs	Returns the coefficients of the nodes you select.
entropy	Returns the entropies of the nodes you select.
path out	Returns the paths of the nodes you select.
error out	Contains error information. This output provides standard error out functionality.

This Express VI operates similarly to the following VIs and functions:

WA Create WP Session
WA WP Decomposition
WA WP Split
WA WP Read Node
WA WP Read Tree Structure
WA WP Read Entropy
WA Dispose WP Session
WA WP Reconstruction