Newsletter - August 2012

GPR-SLICE users,

I would like to welcome the following organizations to the GPR-SLICE community

1. University of Bologna, Italy 2. Subsurface Detection, South Africa 3. Underground Imaging Technologies, New York (www.UIT-Systems.com) 4. Digital Concrete Scanning, California (www.digitalconcretescanning.com) 5. Surface Search (www.surfacesearch.com) 6. Dept of Geography, National University of Ireland, Maynooth 7. Chemia Servis, Slovakia (www.chemiaservis.sk) 8. Center for Research and Archaeology of the Southern Levant, Israel 9. GMB GmbH, Germany 10.GeoCarta, France 11.Geotec Engineering and Environmental Geophysics Ltd, Israel (www.geotec.co.il) 12.McCullough Archaeological Services, LLC, Fort Wayne, Indiana (www.archaeologicalservice.com) 13.Dept of Geology, Brigham Young University, Utah 14.Dept of Geology, University of Illinois, Urbana 15.Seek Tech Inc., San Diego, California (www.seektechicom) 16.Southeast Archaeological Center, National Park Service, Florida 17.Kenaitze Indian Tribe, Alaska 18.Norwegian Institute of Cultural Heritage, Oslo, Norway

GPR-SLICE V7.0 www.GPR-SURVEY.com 19.Geoscanners AB, Sweden (www.geoscanners.com) 20.Geoscience Consulting LLC, Montgomery, Alabama (www.geoscienceconsulting.com) 21.Dept of Geology and Environmental Sciences, College of Charleston, SC 22.Geometrik Muhendislik, Turkey 23.Dept of Archaeology, University of Alberta, Canada

In addition, GPRSIM licenses were delivered Saint-Gobain Receherche, Paris France and to GMB GmbH in Germany.

GPR-SLICE Developments

I am happy to announce that Dr. Alex Novo is now working for GPR-SLICE assisting with support and training. Alex received his Phd at the University of Vigo in the Engineering Forestry department where he was fully engaged in GPR research. His thesis heavily used GPR-SLICE software. Many of the developments, primarily with multi-channel imaging in the software came from consultations and requests from Alex to expand the software for capabilities into many more research activities. He is fully capable and has a complete understanding of the software. Alex started the www.GPR-SLICE.es website in 2011 and is also running a Facebook and Linked-In group for GPR-SLICE. He can be reached at:

[email protected] skype: xandrenovo

As you can see the growth of GPR-SLICE is continuing and my own time to provide customized support to everyone is impossible now. For longer technical questions please begin to seek answers from Alex as well. Depending on the work flow here I will start forwarding some support emails to Alex as well that are directed to me. I will be concentrating my efforts on software development. Also, for users that need complete retraining on the software for 2-3 hours, this now requires payment on the Subscribers Only page. We are always available for small questions for 10-15 min anytime during the life of the subscription and these are always complimentary. We often find that many companies pass the GPR responsibilities to untrained users and the person with the knowledge has left the company. It is crucial that when this happens at an organization, that complete new training be scheduled. Also, we would like to request that support questions on the weekend unless of dire need will not get fully addressed till the start of the workweek. (For accounting inquiries please contact yuki@gpr- survey.com).

GPR-SLICE V7.0 www.GPR-SURVEY.com Software Updates

Among the improvements and requests added to GPR-SLICE V7.0 Software over the last 3 months are:

 Max(X,Y) grid math for decoupled grids  Vector volume warping/writing following the digital elevation model  Radargram appending  BlueBox Batch process for all multi-channel systems through to auto volume compilation  Multi-channel 0ns editing channel-by-channel  Autoset background filter settings  Amplitude smoothing added to Horizon Detection menu  Re-export of horizon detection measurables  Basic DXF time slice output  Yaw files standardized for vector imaging  Time slice area statistics available in OpenGL Volume

Some of the more important additions to GPR-SLICE are further discussed:

Max(X,Y) Grid Math

XY decoupled gridding for enhancing linear features from cross surveys has a new option for further enhancements. Recently at GPR2012 in working with a dataset supplied by Andrew Strange at CSIRO in Australia over a concrete survey, we discovered that overlay analysis shows better imagery then using traditional grid math where the X and Y grids are added. Overlay analysis is implemented using a new option called Max(X,Y) in the Grid menu. The procedure in the Grid menu will chose the maximum value of the X and Y decoupled grids and place into the output grid. Comparison of the traditional grid math and the Max(X,Y) option is shown in Figure 1. Traditional addition of the independently gridded X and Y datasets which were completed with elliptical searching, shows simple addition to have more dotty amplitudes at the crossovers between rebar in the image. The Max(X,Y) procedure because it only takes the peak response between the two grids shows more even amplitudes. These observations can be understood in that the addition will double the amplitudes over the intersections (particularly when the profile spacing is equivalent to the rebar spacing). Choosing the Max(X,Y) between the two grids will not overweight the rebar intersections.

GPR-SLICE V7.0 www.GPR-SURVEY.com Figure 1. Example of Grid math operations with Max(X,Y) versus simple X+Y addition from decoupled grid generation. The Max(X,Y) gives shows better constant amplitude mapping along the rebar.

GPR-SLICE V7.0 www.GPR-SURVEY.com Because the Max(X,Y) is a very useful operation for concrete imaging or for sites with linear features parallel to the profiled lines is so valuable, it is now also included as a setting in BlueBox Batch operations. Shown in Figure 2 is a BlueBox for XY Decoupled Gridding + Edit + RSP which has settings that can chose X+Y or Max(X,Y) operations.

Max(X,Y) is essentially overlay analysis however the individual transforms are not being applied - simply the binary process of using the peak value between the two decoupled grids. There is an option to weight one of the grids more heavily with the multiplier parameter provided. in the Grid Menu.

Figure 2. Location of the new Max(X,Y) Grid Math operation in the BlueBox Batch menu.

Vector Volume

GPR-SLICE V7.0 www.GPR-SURVEY.com GPR-SLICE Static corrections now incorporate vector topography. Using the new Vector Topo button in the Static corrections menu, flat rectangular volumes will be warped into their vector space using the surface normals of the digital elevation model. The topography grid file - topo1.grd - is used to position the grid cells into their vector space assuming the antenna was perfectly parallel with the surface of the topographic site. The repositioning and warping of the cells into their correct 3D space can create voxel gaps in the newly created binary 3D volume. A button to conveniently interpolate the gap using nearest neighbors can be applied clicked in the menu. The user should first look at the raw converted file to see if gaps are significant. If not, then a simple gap interpolation with a x, y interpolate grid cell length of 1 should suffice. An example of vector warped volume is shown in Figure 3. The vector volume is written with the append identifier "topo-" added onto the flat rectangular volume. If this volume is subsequently interpolated the identifier "int" will be further added onto the volume naming automatically. From this menu standard topographically adjusted volumes which simply shift the grid cells vertically can also be made using the Standard Top.

Figure 3. Vector warping and writing of a new volume adjusted for topography that accounts for the surface normal of the digital elevation model.

Radargram Appending

GPR-SLICE V7.0 www.GPR-SURVEY.com All the radargrams written into an information file can be appended to a single radargram file using the new Append All Radargrams button in the Radargram Edit menu (Figure 4). The option is provided in the menu traditionally used for just time 0 editing. After the appending option is completed, the user will need to create a customized information file to display the appended radargram name.

Figure 4. A new option in the Radargram Edit menu allows for appending all the radargrams listed in an information file to a single binary radargram.

BlueBox Batch operations for Multi-channel systems

GPR-SLICE V7.0 www.GPR-SURVEY.com BlueBox Batch operations for all multi-channel GPR systems have been enhanced for complete automatic volume compilation. With these new options, the multi-channel processing can be completely automated after the information files are created - all the way through to volume generation. The 3D volume is now controlled by the xy grid cell size set in the Multi- Channel Volume Generation menu. The Help Set button will automatically detect the size of the site and set these values in the menu slots. The Help Set button can be checked on via the BlueBox Batch operations as well. With this new operation, the user will normally work with a particular GPR system at the same desired density for the XY cell size. The Z grid cells can be independently set. Interpolate GAP on the 3D volume can also be triggered in the BlueBox should the desired 3D volume be denser then that cross-line separation of the antenna elements. The BlueBox Batch menu will indicate the folder in which the 3D volume will be generated. For RSP Customized BlueBox operations this will be the last folder operated on in the Filter menu. For hardwired Spectral Whitening or Bandpass BlueBox operations, the last folder is the Hilbert folder. Should the user not want the Hilbert folder initially to be generated, then the BlueBox with customized RSP menus can be run to get the desired last folder compiled to a volume.

Figure 5. BlueBox Batch menus for Multi-channel projects now have complete automatic processing operations all the way through to 3D volume compilation. Multi-channel 0ns Editing Channel-by-Channel

GPR-SLICE V7.0 www.GPR-SURVEY.com A new option for multi-channel licenses to compute the average 0ns offset across the entire channel dataset is now available. Channel-by-channel operations compute the average 0ns across the entire channel dataset (Figure 4). This option can be critical to removing stripping noise. Particularly on sites where coupling changes alter the channel groundwave reflection, channel-by-channel detection can give a better estimate the applying line-by-line time zero detection. Channel-by-channel operations ensures that a time zero average across the entire channel dataset is implemented in the processing. BlueBox Batch operations can also be set using the desired radio buttons in the menu.

Autoset Background Filtering Setting

Figure 6. Autoset background filter length.

Background filtering now has automatic option to set the filter length to an artificially high value, e.g. 99000 prior to running the filter (Figure 6). With this checkbox engaged, the background filter will automatically compute the average scan across the whole radargram. For customized filter lengths, the autoset checkbox can be unclicked and edited as desired. In the past, some users neglected to adjust the default filter length on new projects and this new autoset option will negate the need to manually place in a large filter length for computing the average scan.

Smoothing of the Amplitude of Detected Horizons

For GPR-SLICE licenses with the road+bridgedeck module, there is a new option to smooth the amplitude of the detected horizons (Figure 7). The detected horizon amplitude follows the filter length setting in the upper part

GPR-SLICE V7.0 www.GPR-SURVEY.com of the Horizon Detection and Mapping menu. The smoothed amplitude is a running average over the desired filtered length. The smoothed amplitude can be useful in metal plate calibrations and horizon depth estimates from air launched antenna surveys.

Figure 7. Detected horizons and their corresponding amplitudes can be smoothed in the Horizon detections menu. This smoothing of amplitudes is important for calculated estimates of ground dielectrics based on metal plate calibration for air launched antenna.

Re-Export of Horizon Thicknesses

Once horizons are detected they can be compiled in several formats (Figure 8). Recently the export horizons which can be recompiled to the desired linear density along the GPR track was enhanced with further features at the request of users. The Recompile Export-HorzXYZN operation will report the detected horizon and note the median, average, maximum

GPR-SLICE V7.0 www.GPR-SURVEY.com and minimum in the file. These export files are all written in the \dat\ folder of the project.

Figure 8. New format for recompiled horizon detection file with statistical reporting.

Basic DXF Output of Time Slices

Rudimentary DXF output of displayed time slices can be made in the Pixel Map menu (Figure 9). One of the problems with the native DXF files in autocad is that they do NOT contain color palettes. The files rely on the palette set in the autocad software. The default palette is lacking many color definitions and also is limited to 256 colors. During the generation of the DXF file made from the time slices is that the software will ask if you want GPR-SLICE to generate the DXF file to the nearest RGB color found in the native DXF palette. If this is done, the GPR-SLICE will write a DXF file that will discover the closest RGB color of the default DXF palette. The DXF image has significantly less color contours and thus can appear decimated. An option to write the DXF file without degrading to the default DXF file is also available. If this method is done on generation and answering the message box on the DXF generation, then the DXF file will be written with information on the color number in a 256 palette. The user will then need to specifically generate the same color palette in their autocad software to get a similar image shown in the Pixel Map menu. Other autocad formats such as binary DWG will be investigated to see if improvements on the default coloring of time slices can be achieved. The DXF file is written without labels, similarly to KMZ and world file generation.

GPR-SLICE V7.0 www.GPR-SURVEY.com Figure 9. Basic DXF output of time slices is possible in the Pixel Map menu using the new DXF checkbox. (The transformation to the nearest default DXF colors may have undesired colored decimation).

Yaw file definition

Several users have started generating GPS vector information and several formats have come to attention. The one originally working and developed has date, time, yaw, pitch, roll. An example of a yaw file made for a radargram with this format is:

Time can also be input without ":" as these are detected on conversion. Some accelerometers place other information in columns beyond the fifth such as accelerations components and temperature etc...We currently are only reading up to the fifth column of the imported *.yaw files.

GPR-SLICE V7.0 www.GPR-SURVEY.com Time Slice Area Statistics

A new button in OpenGL Volume will provide area statistics based on the isosurface percent setting. Just clicking the Z plane and showing it to any level in the volume, then clicking the “stat” button in the menu will give the total area on the time slice greater or equal to the desired iso threshold (Figure 10). If you just show the Z plane you will not really know the exact location of the area. The best way to see the area is to show the isosurface first – store it - then display the desired z plane – followed by clicking the stat button. One can also first place the isosurface – then place a z plane – followed by adjusting the slider bar to match the isosurface – followed by clicking the stat button. The focus option can also be engaged to only provide the area statistic from a selected part of the volume. It is common for geotechnical firms to provide estimates of the areal size of anomalies such as for delamination on bridgedecks, void sizes, measurements of fill areas etc. The new Stat option will make reporting this information easier.

Figure 10. Location of the button to map the total XY area of a desired anomaly threshold within the Z scan.

GPR-SLICE V7.0 www.GPR-SURVEY.com Other features and options added to GPR-SLICE include:

 IDS Duo and IDS Stream Multi-channel system Scan Stamp GPS navigation added  Sensors and Software Multi-channel multiplex formats added to Convert menu  Underground Imaging Technologies native MAP navigation format added to Create New Info menu for Terravision equipment  Time slice grid identifiers added to Mosaic Correction menu for ease of input  SEGY Volume export added to Filter menu  Import of *.xyz files with comma delimitation of random navigation assigned to each radargram in the Edit Info File menu using the new XYZ to NAV button  Focus option for drawing objects in OpenGL Volume will connect with other focused/unfocused drawn objects  GPS time latency added to GPS Track Menu  ASCII 3D volume export in the format x,y,z,a of vector adjusted radargrams available in the OpenGL Vector Radar menu.  Gain points and their values identified in all 16 bit convert menus for the different manufacturers along with options to adjust with toggle buttons

In addition, several important bug fixes were made and all users should download the latest software.

Recent Events

A GPR-SLICE workshop was taught at the Seminole Tribe of Florida in late June. A GPR-SLICE 2 day workshop was taught in Woodland Hills March 23-24 with attendees from Oklahoma, South Africa, Canada, Mexico, and California. Alex Novo ran a 2 day workshop on GPR-SLICE Multi-channel processing for 9 employees of GeoCarta in France in May.

Upcoming Events

July 26-August 5, 2012, Joint GPR researches with Professor Yasuyuki Murakami, Ehime University Japan.

GPR-SLICE V7.0 www.GPR-SURVEY.com September 21-29, 2012 - International Technical Workshop "Remote Sensing Techniques in Archaeological Research" (RESTAR) http://www.archaeolandscapes.eu/index.php/news-a-events/news/166- technical-workshop-qremote-sensing-techniques-in-archaeological-research- restarq.html. GPR surveys and GPR-SLICE processing sessions to be featured in the workshop along with other geophysical methods and lectures. For more information on this workshop in 2012, please contact Dr. Apostolos Sarris Laboratory of Geophysical - Satellite Remote Sensing & Archaeo- environment, ([email protected])

best wishes, Dean ______Dean Goodman Geophysicist, Phd GPR-SLICE Software Geophysical Archaeometry Laboratory 20014 Gypsy Ln Woodland Hills CA 91364 [email protected] [email protected] www.GPR-SURVEY.com

*This newsletters is available in *.doc form on the Subscribers Only page of the website

GPR-SLICE V7.0 www.GPR-SURVEY.com