CALC MENU
The CALC menu has many functions for processing the data in various ways.

Refresh
Refresh takes the data back to its initial form when it was read into the program. It re-plots the first CWT and the original seismogram.

Undo
This function undoes the last operation of the GUI.

Compute CWT
The CWT is computed for the seismogram shown in the seismogram plot. The CWT TFR is then plotted in the top window. Further processing cannot happen until the CWT is computed.

Estimate Noise
The noise is estimated for a portion of the seismogram defined in the "Choose Noise Time Bounds" box in the lower left. The default values for begin and end times are 0 and 1, respectively. Here is an example with the canonical seismogram using a time bound of [0, 60] s.
On choosing Estimate Noise, the GUI finds the mean and standard deviation at each scale in the time interval chosen. Note that "Donoho's Thereshold Criterion" was chosen for this calculation. A separate plot is produced showing the result of calculating the mean and the threshold function:
In addition, the non-Gaussianity of the distribution of wavelet coefficients is also plotted as a function of wavelet scale:
The wavelet distribution is approximately Gaussian for scales that fall in between the two horizontal lines bounding the value of zero.
The noise must be estimated before using the remainder of the commands in the CALC menu.
Note that the "Donoho's Threshold Criterion" radiobutton must be pressed if you want to use this parameter in the noise or signal thresholding schemes.
If the 'ECDF Method" button is pressed,
then the threshold is computed using the empirical cumulative probability distribution (ECDF) method. The result gives a plot of the mean and the ECDF threshold:
Using the ECDF method is recommended.

Hard Threshold Noise or Soft Threshold Noise
These functions remove noise and reveal the signal.
Here is quick tutorial on CWT theory that explains hard and soft thresholding:

Hard Threshold Signal or Soft Threshold Signal
These functions remove the signal and keep the noise. This might be useful for ambient noise correlation studies to obtain noise Green's functions.
Here's an example of removing the explosion source from the inferred noise field using the hard thresholding method:

Correlate Template
To use this function, you need to read a CWT template into BCseis using the Read CWT Template File from the File menu. In addition, if you want the polygon plotted on the CWT scalogram, use Read Polygon File from the File menu as well.
A template file (RF3016CWT.mat) and a polygon file (RF3016polygon.mat) are contained in the /data directory.
This function is used to experiment with different templates and polygons on particular seismic traces from elements of an array.
The correlation is performed by
1) Calculating |W(a,tau)|^3 for both the template and data CWT.
2) Shifting the template in time lag, tau, in the interval of + and - "Correlation Time Tolerance" (seen in the bottom right corner of the GUI).
3) Multiplying over all scales and integrating.
"Correlation Time Tolerance" was implemented to speed the process up for array data since the moveout of particular phases do not change too much over the aperture of typical arrays. This value can be changed as desired in the edit box.
Here is the result of correlating the RF3016CWT.mat template with the original data displayed at the top of the page. The polygon file has also been read in. The "TLIM" button was pressed to refresh both plots to obtain the polygon outline.
Here is the correlation plot that results
Pressing the "Include Block" on the GUI will use the polygon to zero out all other CWT coefficients to yield the estimate, in this case, for the Rayleigh wave.

SNR Detector
A signal detector based on the Signal-to-Noise Ratio (SNR) is implemented with this menu item. A Signal-to-Noise seismogram is computed by dividing the noise (plus a "water level" parameter) into the CWT of the entire seismogram. Each CWT coefficient is replaced by the ratio of the original complex coefficient by the absolute value of the noise estimate plus a percentage of the maximum value of the noise. N lower bound (see above figure) is the parameter that defines this percentage.

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