Mala Mira processing in GPR-SLICE v.70

Addendum Manual (update November 1, 2010)

Mala Mira processing in GPR-SLICE v.70 (update November 1, 2010)

The basic processes needed to use Mala Mira multi-channel GPR systems are briefly itemized:

1) Create an info file with the names of the main tracks. There are 2 ways to create this: A) using the Create Info button (Figure 1A) or B) Using the Import option (Figure 1B) and searching for the \raw\ folder of the project.

Figure 1A. Info file creation of the main Mala Mira track names using the Create Info button.

Figure 1B. Creation of the main Mala Mira track info file via the Import button to propagate the names of the files inside the \raw\ folder.

2) Next step is to use the standard buttons step 1- Mala Get TS followed by step 2- Mira to Nav, which generates the *.rd3.gps files of the main track, and finally step 3- GPS get list to update the number of GPS listings in the information file (Figure 2). The user can at this time use the GPS track menu optionally to filter and condition the main GPS tracks should there be need to.

Figure 2. In the Edit Info File menu, 3 buttons are needed to generated the *.rd3.gps files of the main Mira tracks.

3) The next operation is to extract all the radargrams from the main track names using the new Mira Extract button in the Convert menu (Figure 3). This will make extracted radargrams in the \raw\ folder with the naming convention *-N.rd3 where N is the channel number.

Figure 3. Individual radargrams for each antenna pair from the multi-plexed main track radargrams are generated to create *-1.rd3 to *-16.rd3 filenames in the \raw\ folder of the project.

4) After the extraction to individual profiles per each channel, a new infochannels.dat file is generated containing the offset of the channel with the GPS antenna (Figure 4). In this configuration the separation between antennas is 0.12 and the GPS is located above channel 1.

Figure 4. Generation of the infochannels.dat file.

5) The Array to Nav button is used to generate the individual channel tracks. The calculation includes the recorded offset in X and/or Y and employs monitoring the track orientation by looking at the trend between 2-3 adjacent GPS points.

Figure 5. The individual channels navigation files are generated using the Array To Nav button.

6) After this is done the user will want to apply standard signal processing such as

0ns radargram editing Bandpass or spectral whitening as desired Background removal (should striation/line noise remain)

Standard time slice operations can commence.

In addition, a new menu to quickly generate pulse image volumes of the Mala Mira systems and any multi-channel or non multi-channel closely spaced data are available currently to just Multi-Channel users in the Radar pull down menu (Figure 6). The user must set the maximum number of grid cells in X or Y and Z (keeping in mind the resolution they want in the volume). A button called “Interpolate Gap” can be used to fill in gaps between tracks. The Smooth button is the same as the 3x3x3 low pass 3D volume smoother in the Grid Menu for convenience.

Figure 6. A new (beta) menu to compile the closely spaced radargrams or multi-channel array s into a single – noninterpolated volume is available using the Create Radar 3D file button.

An example of the new 3D Radargram fast pulse volume compilation menu is shown below (Figure 7) along with its Open GL output.

Figure 7. Example of the location of the new multi-channel fast pulse volume generator along with output of the volume in Open Gl.

Examples of some imaging in GPR-SLICE v7.0 with the Mala Mira multi-channel GPR system through the normal 2D time slice menus (Figure 8).

Figure 8. Example images from the Mala Mira system collected at Carnuntum (data courtesy of Mala GeoScience).