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Program Manipulation

Enhancing (cleaning vertical grid)

This tool is intended to erase the vertical grid, that causes the fallacious deviation from true curve shape during the automatic segments selection. This is important, when the steady bold vertical lines take place on the seismogram's image (fig. 9.a). After the vertical grid is removed, the automated selection has no obstacles and so digitization may be performed by minimal user's efforts (fig. 9.b).

To remove the vertical grid, a user has to click Enhancing button on the "Etc" panel. He may also to set previously a new value of Saturation, which is regarded as percentage of black pixels in column, that is a criterion to consider this column as a vertical scale line, and thus to be deleted.

Despiking and filtering

On the figure one may see how the vertical grid influences to digitizing: Several spikes and total roughness are arised.
After enhancing the number of spikes have become less and the average amplitude of the roughness also has been decreased.

When the mode "Dispiking" was switched on all spikes were removed. Before digitizing a user has a possibility to tune the size of median window. The more size of window is set up the more smoothing effect takes place so user must be accurate to avoid the distortion of wavelets. In our opinion the default size = 7 is the most appropriate value.

Nevertheless in spite of Dispiking mode certain roughness remains yet. Implementation of the smoothing filtering removes roughness entirely.
Image of the first wavelet of this seismogram is shown below. To provide the clearness of the figure, other traces are removed and image iz zoomed with scale coefficient=2. The notations of processing stages (a,b,c,d) are saved.

To get a good results it is important to set the appropriate frequency band for filtering. The values of band boundaries are set in the command line of "Etc" panel with special conditional inits - 1/pixels. This values may be evaluated using the dominant period of the oscillation (in pixels), which must be previously measured by the user.

Measuring

In order to get the coordinates of a cursor and measure the distance between two arbitrary points a user should set the "Msr" mode in the main window. In this mode the position's coordinates of moving cursor are reflected at the left part of a footer on the main window.

When a user clicks the left mouse button the position of the cursor (first point) is marked with the red cross and fixed at the screen. Further cursor moving is followed at the right part of a footer.

When a user clicks the right mouse button the position of the cursor (second point) is marked with the red cross and fixed at the screen. At the same time both points are connected with the line and the distance between them is printed at the footer.

 
 
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