| Parameter | Description |
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| 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 if you select From file in the Data Source section.
- Ask user 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 if you select From file in the Data Source section.
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| Original and Denoised Signal | Displays the original signal and the signal after denoising. |
| Transform Settings | Contains the following options:
- Transform type—Specifies to use the discrete wavelet transform or undecimated wavelet transform to denoise the signal.
- 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 (FBI, Biorthogonal (biorx_x)), 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.
- 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.
- Analysis wavelet—Displays the analysis wavelet function.
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| Threshold Settings | Contains the following options:
- Soft threshold—Specifies to use the soft thresholding method. The default is to use the soft thresholding method. If you remove the checkmark from the Soft threshold checkbox, the VI uses the hard thresholding method.
- Thresholding rule—Specifies the threshold selection rules. The default is SURE, which indicates that the VI uses the principle of Stein's Unbiased Risk Estimate (SURE) to estimate the threshold. If you select Hybrid, the VI finds a compromise between the SURE method and the Universal method. When the signal-to-noise ratio of the noisy signal is very low, the VI uses the Universal method to estimate the threshold. If you select Universal, the VI sets the threshold to sqrt(2×log(Ls)), where Ls is the signal length. If you select Minimax, the VI uses the minimax principle to estimate the threshold.
- Rescaling method—Specifies the method to use to estimate the noise variance at each level. The default is single level, which indicates that the noise is white and that the VI estimates the noise standard deviation from the wavelet coefficients at the first level. The VI uses the noise variance to rescale the threshold. Therefore, you can update the thresholds with the noise variance. Selecting one indicates that the noise is white with unit variance. Selecting multiple levels indicates that the noise does not have to be white and that the VI estimates the noise standard deviation at each level independently.
- Option for approx.—Specifies the operation for the approximation coefficients from the wavelet decomposition. The default is none, which indicates that the VI keeps the approximation coefficients unchanged. If you select threshold, the VI applies the same thresholding operation to the approximation coefficients. If you select detrend, the VI sets the approximation coefficients to 0.
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| Data Type and Display Mode | Contains the following options:
- Data type—Specifies the data type of the input signal. Data type is available only when you select From terminal in Data Source. When you select From file in Data Source, the VI determines the type of input signal based on the contents of the file.
- Display mode—Specifies the display mode of complex signals. Display mode is available only when you select complex in Data type.
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