Key Words:
*.plt
*.tmp
GSSI GPS/GPR
cepstrum
deconvolution
Open GL
Newsletter – November 2007
GPR-SLICE Users,
I would like to welcome the following organizations to the GPR-SLICE community:
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Coastal Geology & Geophysics, University of Massachusetts
Texas Archaeological Research Laboratory, University of Texas
Archaeological Institute SAS, Nitra, Slovakia
Dr. Allen Gontz, an Assistant Professor at the University of Massachusetts was introduced to
GPR-SLICE by Dr. John Steinberg and they were both using the software recently for GPR
surveys to discover Viking long houses in Iceland. Allen is our first user to do a complete
GPR/GPS survey using Mala Geoscience equipment and we just ran through all the new
operations to process Mala GPR/GPS data.
Dr. Dale Hudler at the University of Texas was recommended to the software by another one
of our users, Chet Walker at Archaeo Geophysical Associates which is also located in
Texas. Dale is an Archaeologist at the University of Texas in Austin.
Dr. Jan Tirpak of the Archaeological Institute in Nitra has seen results from other GPR-SLICE
users in Europe and recently at the Archaeological Prospection meeting in Slovakia. The
Archaeological Institute was the main sponsor and organizer for the most recent
Archaeological Prospection meeting in Slovakia in September 2007.
I am very grateful for our users that have recommended GPR-SLICE to other people. Even
presenting our software four to fives times a year at professional exhibits is second to what
new and past users have brought to our growth. We are deeply indebted to all of you for
sustaining this software effort.
Updates:
The last 7 weeks have seen some more visualization tools being added to GPR-SLICE.
Additions to OpenGL visualization and integration of GPR/GPS for GSSI SIR 3000 users are
some of the highlights. Among the main updates now on the website are:
GPR_Slice V5.0 www.gpr-survey.com
1. Open GL Radargram visualization
2. Open GL Volume visualization (combining 3D time slices, radargrams, and horizon
surfaces in a single volume display)
3. Complete GPR/GPS integration for GSSI SIR 3000
4. Multiple horizon surface designation
5. Cepstrum Deconvolution
6. IDS of Italy quick editing buttons added
1) Open GL Radargram visualization
A new Open GL menu for displaying radargrams is now available. For those licenses with
these extended options, one can now rotate, tilt and store any combinations of
radargrams to the Open GL graphic screen. An example of a radargram displays are
shown in Figure 1 and 2. In the OpenGL Radar menu the user can display a radargram
from any folder or combinations of folders. To do this there is a "Store" button which
will preserve the radargram (s) with the current folder. The user can then switch to
another folder midstream and start displaying radargrams from the new active folder.
This can allow quick 3D viewing with different radargrams folders in the same view. You
can not show the same radargram in the volume from a different folder, but you can
show an adjacent radargram that has had different processing. The OpenGL Radargram
menu can also be used for GPS radargram displays.
Animations can also be generated automatically in the Open GL Radargram as well as
in the 2D Open GL menus. The user simply sets an identifier in the menu and then clicks
the button Generate Animation. At the end of the drawn screen, a message box will
appear and ask if you want to update the Animation List. This automatic updating has
also been placed in all areas in GPR-SLICE including OpenGL graphics as well as the
regular graphic menus in the software.
2) Open GL Volume Visualization
A separate menu has been developed which now allows mixing and matching the 3D
volume slices along with 3D radargrams displays. Shown in Figure 3, is an example of a
GPR radargram being displayed along with 3D time slice fences. The user can store any
element to the screen using the "Store" button and then toggle through to other desired
displays by clicking the appropriate buttons - Radar, X Y or Z, or Horizon. (There is
some overlap in functionality of the new Open GL Volume menu with the Open GL
Radargrams menu. I believe it is useful to have a separate option menu for just
radargram visualizations as their maybe a future need to develop these visualizations for
an extended radargram only menu as well).
An interesting view for the OpenGL Volume display is to see the radargram side-by-side
with a fence diagram in the exact location. One can visualize the GPR-SLICE volume
image with the raw radargram to see how reflections are imaged/transformed by the
slice operations. One will be able to find for themselves that some data, in which no
GPR_Slice V5.0 www.gpr-survey.com
coherent reflections seen in the radargrams, are clearly illuminated in the 3D amplitude
volume generated in the software.
3) GSSI GPR/GPS SIR 3000 Integration
Dr. Andy Kathage of GeoHiRES in Germany, who is also the International Sales
Representative for GSSI, recently sent the first GSSI dataset in which he was able to
hook up a RTK GPS system to the SIR 3000. The button in the Edit Info File menu called
GSSI to UTM is now engaged. This button will automatically read the *.tmf files that the
SIR 3000 generates and will extract the synced portion of the NMEA strings from the
*.plt files. The button will of course automatically convert the latitude and longitude in
the *.plt files to UTM and put them into *.dzt.gps format which is needed for GPR/GPS
processing. An example of GPR/GPS imaging using the new buttons in the software is
shown in Figure 4 (data courtesy of Andy Kathage, www.GeoHIRes.com).
The process of doing GPR/GPS imagining with the SIR 3000 is now very simple and
straightforward. However, your current SIR 3000 equipment is not enough to hook any
GPS system. Dan Welch from GSSI mentions that you will first need to purchase an
Accumen DSR data bridge in order to be able to have any GPS systems integrate into
your SIR 3000. According to Dan,
"....the databridge is a piece of hardware that is about the size of two decks of
cards. It has a USB connector to go the the 3000 (for power) and a serial input from the
GPS and a serial output to the 3000. It stores data on a CF card. The idea is to have a
universal device which will mate with just about anybody's GPS. At the close of each
data file, the 3000 downloads the appropriate information from the databridge and
stores it internally. The necessary files get automatically transferred with the DZT file.
They are also tagged with the same root name as the DZT....."
So if you are interested in GSSI GPR/GPS imaging with the SIR 3000, GPR-SLICE is
ready to go. For those that have not done GPR/GPS imaging you will be amazed at how
easy it is to do imaging in the software for these kinds of surveys.
Note: The possibility of GPS fallout still exists with any GPR equipment. However, GPRSLICE is already equipped to handle typical fallout from the SIR 3000 GPS hookup.
Using Andy's data, we have demonstrated the use of the Int Time GPS button in the GPS
track menu (Figure 4). Clicking this button, the software will discover GPS points where
seconds are missing, and it will automatically interpolate the GPS reading. The
interpolated points will be drawn in red in the new Track menu. The software currently
will stop the user from interpolating if there are more than 10 seconds of missed data. I
can open this up and allow the user to continue with interpolating beyond 10 seconds of
missed data. If this happens please let me know and I can change the software to allow
processing to continue for such poorly navigated dataset. However, one should become
skeptical of the quality of their navigation is so many points were missed in the field or
GPS was lost for such an extended time.
GPR_Slice V5.0 www.gpr-survey.com
Note: The GSSI equipment does not currently export the scan number for each GPS
reading so we recommend not recording extended GPR lines. Timing information on the
start and end times for a radargram are stored within the *.tmf header. GPR-SLICE
reads these headers and takes the necessary information for the GPS log. Loss of
syncing or the possibility of a non-constant number of scans per unit time can create
uncorrectable scan latency in the data. Because the scan numbers are not exported for
this equipment, you will need to use the Artificial Marker button for the navigation of
GSSI GPS surveys. However, the example data that Andy sent had nearly 20,000 scans
of data for one line, which represented over 10 minutes of data collection. The time
slices had no scan latency and the images were correctly determined after the Int Time
GPS button was expedited. This indicates that SIR 3000 is generating a constant
number of scans per seconds and this very reliable. In any event, we recommend taking
shorter GPS line segments for GPR-SLICE processing.
Note: There is a GSSI to NAV button also in the Edit Info File menu. This button is being
reserved for total station navigation. The button is not active yet as we are waiting for
the first user to generate a GPR survey with total station navigation. Sensors and
Software formats for Total Station use the same format for GPS NMEA strings except
that the latitude and longitude are local total station coordinates. GPR-SLICE simply
writes the *.*.gps files when converting these navigation files without using the UTM
conversion. We imagine that the GSSI total station formats which eventually develop
will be the same, where the NMEA string contains the local coordinates and not lat/long.
Once someone has actually done this with the SIR 3000, please send the navigation files
along and we will integrate the formats in to the Edit Info File menu. There are
several companies now marketing Ultra Wide Band tracking systems in the 5-7 GHz
range which can work inside thick forests , buildings or even factories to track all
resources real time to several centimeters. One does not need line of site to use these
tracking systems. Eventually, the accuracy and the complete coverage of these
navigation systems will compete or entirely make GPS an "obsolete" technology before
it even becomes mainstay in the GPR world, since there is no loss of navigation
coverage.
4) Multiple Horizon Surface Detection
Multiple horizon surfaces or stratigraphic surfaces can be detected or drawn in the Static
Menu. The new designation for which surface is being compiled is set in the Static
Menu. Once these are detected automatically or by a user drawn profile on the
radargrams, the user can then compile the horizon data to horizon1-N.dat for gridding
operations. These drawn horizons can also be used as elements for display in the new
Open GL Volume menu. An example of this is shown in Figure 6 where radargrams, 3D
time slices fences and detected horizons are shown.
5) Cepstrum Deconvolution
Deconvolution is a signal process which can be valuable in removing multiples or echoes
in GPR return pulses. Often, GPR pulses contain many reflections which are simply
GPR_Slice V5.0 www.gpr-survey.com
multiple reflections of radar waves from the same reflector. One example of a multiple
reflection is a wave that travel downs to a reflector, back up to the ground surface to be
reflected by the air-ground interface, and then back down into the ground only to bounce
off the same reflector again. One method for reducing the energy from multiples is the
cepstrum deconvolution process. In this signal process, the GPR pulses are converted to
the spectral domain using Fast Fourier Transforms, the logarithm of the spectral
components is computed, and then the inverse Fourier Transforms is made to convert
back to the time domain - deconvoluted pulse. Taking the logarithm of the spectral
components has the effect to smooth out amplitude undulations in spectral frequencies,
and reduce the influence of multiple reflections.
Cepstrum deconvolution is now available in the FILTER menu. Cepstrum deconvoluted
radargrams are written to their own unique folder called \deconv\. There are many
other kinds of deconvolution algorithms, and none of them is perfect medicine for
removing multiples. We may provide additions to deconvolution algorithms in future
releases.
6) IDS of Italy quickbuttons
Wojtek Laskowski of Murphys Survey in Ireland became our first user that has the IDS of
Italy GPR system (http://www.idscompany.it/index.php?id_div=4). We have included
quick editing buttons to create information files for this Italian manufacturer. IDS of
Italy normally exhibit at all the international conferences on GPR. However, to date I am
not aware of any users of this equipment in the US because of FCC regulations.
Operational Notes:
VISTA versus XP)
We are now working with a VISTA operating system to continue the development of
GPR-SLICE and we are also discovering several issues that you will need to address on
VISTA machines. The most important discovery is that you will need to become the
administrator of your own computer if you want to run GPR-SLICE in the current
c:\program files\slice\v5.0 folder. We have not changed the file folder, and currently all
users are required to load the software in this location. VISTA however, if you are not
the administrator of your own computer, will not allow the users to alter any file located
in the \program files\ directory as these are locked. GPR-SLICE writes transparent work
files in the v5.0 folder and thus if your are not the administrator you will not be able to
run the program or see changes from running the program since work files can not be
altered. To change the administrator privileges you need to go the User Accounts under
the Control Panel and check off the User Account checkbox and make yourself the
administrator. If there are any system problems in doing this at your company, we may
need to give users an option to run the software outside of the program files directory.
In terms of OpenGL graphics there are some important observations from a limited
number of examples. ATI Radeon graphics cards on VISTA may show some rendering
GPR_Slice V5.0 www.gpr-survey.com
glitches. We have run the same software with NVDIA graphic cards on VISTA and there
are no display problems. In doing further search, I have learned that the drivers on
VISTA with some cards still have some issue and these companies are trying to resolve a
number of problems. OpenGL operations on XP have no problems. One's ability to
effectively run graphics speedily in the software will be a function of your graphics card,
graphics memory and the computer memory. Large files may not display effectively to
the screen.
Another observation is that GPR-SLICE as well as Open GL operations run faster in XP
then on a similar machine with equal or even much better processor speeds in VISTA.
GPR-SLICE and most software packages are not programmed to run multiple threads
within a program that can take advantage of dual-core processing. The dual-core
processor is only helpful in running multiple applications, however, singular applications
may not benefit. We have noticed degradation in processing speed with VISTA. If any
users have more experience with VISTA and can make recommendations regarding
configurations that may speed up data processing in the software, please let us know so
we can share this with the group. There is a Message Forum on the Contacts page of the
website for you to post correspondence as well.
Upcoming Events:
October 28-31: GPR-SLICE will be exhibited at the upcoming Geological Society of
America convention in Denver http://www.geosociety.org/meetings/2007/ We will be at
booth #502. For those that are interested we are planning a dinner either Monday or
Tuesday night depending peoples schedule at the convention. I will also make myself
available for any users that want any one-on-one data processing training either before
or after the exhibit hours. If any users want to get into the exhibit please let us know
and we can reserve a pass for you at the convention center.
November 12-15: The Annual United States Forest Service GPR/GPR-SLICE workshop
is scheduled for Nov 12-15. Velicia Bergstrom who is the Heritage Manager of the
Kisatchie National Forest, and John Ippolito who is the Heritage Manager of the
Grasslands National Forest are the sponsoring organizers for the workshop If you have
not already done so, please register by November 2nd. The information is located on the
Upcoming Events page of the www.GPR-SURVEY.com website. This year's workshop is
sponsored in part by the National Trust for Historic Preservation Grant, the
Fondren Endowed Fund, and the Sue Turner Fund of Louisiana of the National
Trust for Historic Preservation. We are grateful for the yearly sponsorship of the
workshop.
Bryan Haley of the Department of Anthropology, University of Mississippi will be teaching
the beginning class on GPR-SLICE processing. Last year, Bryan had 22 students in
beginning class and he was able to lead the new students all the way from raw data to
presentation displays and 3D animation menu creation. I will be along to teach the
advanced class which will run parallel to the beginning class. The advanced class
schedule will currently include:
GPR_Slice V5.0 www.gpr-survey.com
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GPR/GPS imaging with example datasets for:
Mala, GSSI, and Sensors and Software equipment
GPR-SLICE GIS integration
Signal processing
Multi-grid imaging
Mosaic correction
Staggering correction
Topographic correction
Horizon detection and imaging
Split Screen operations
Overlay Analysis
Open GL visualization
For those users that do not have licenses to use OpenGL, you will have an opportunity to
receive a 45 day subscription to these advanced operations in the software at the
workshop.
We will be having a concentrated effort to introduce GPR/GPS imaging to the users at
the workshop. We are very fortunate to have received permission from several users to
borrow data that they have collected for the training. I want to personally thank Dr.
Allen Gontz for allowing us to use his Mala Geoscience example for instructing users on
GPR/GPS operations with this equipment manufacture. Allen's data was also given
permission for the workshop training by the City Archaeology Program, Department of
the Environment, Boston. Dr. Andreas Kathage has allowed us to use his data at the
workshop to train users on GPR/GPS operations with GSSI equipment. Also, Amzie
Wenning of the Indiana Geological Survey has given permission to use Sensors and
Software GPR/GPS data collected at the Indian Purdue University workshop we had last
summer. All 3 major GPR manufacturer's GPR/GPS surveying operations and imaging
will be addressed at the workshop. For Horizon detection and imaging, Daniela
Hofmann of Wiebe Group in Germany along with the University of Applied Sciences in
Demold/Germany has given us permission to use a dataset for Horizon mapping.
Note: The datasets donated for the workshop can only be used within the workshop and
are not for outside purposes. We thank you for your cooperation in this regard!
Note: We are also inviting users to bring their own datasets that they would like to see
advance processing to handle their own imaging issues with a particular survey. If you
have a chance to send this data in advance of the workshop I can include it in the formal
schedule for the advanced class. Please limit the data to under 50 profiled lines if
possible, or just provide the time slice information if the imaging issues are something
beyond just signal processing or data conversion. Users attending the advanced
class should bring their own notebook computer - the beginning class users do
not need to bring computers as 25 of these are provided in the training room at
the US Forest Service facility.
GPR_Slice V5.0 www.gpr-survey.com
A special guest will be attending the US Forest Service workshop. Higashi Noriaki is from
the Saitobaru Archaeological Museum in Miyazaki, on the Island of Kyushu will becoming
to the workshop. Higashi San is the Head Curator at the museum but he is also the
resident GPR specialist. If you look on our website, License #1 is with Higashi San's
museum. His museum, which is also under the guidance of Hongo Hiromichi, was very
early to realize the potential of GPR for mapping the subsurface archaeology. We began
working at the Saitobaru burial mound park back in 1992 and are still working there
today on many joint projects. Recently, Higashi San's research group which includes the
Geophysical Archaeometry Laboratory, surveyed several Imperial Family Tombs on the
museum grounds (http://saito-muse.pref.miyazaki.jp/collumn/curator7/index.html).
His museum was instrumental in providing many years of GPR research funds to the
Geophysical Archaeometry Laboratory in Japan as well as directly supporting the
software development of GPR-SLICE from DOS to Windows 7 years ago. Without the
Saitobaru Museums support, GPR-SLICE Software would not be available to you today.
Feb 9-12, 2008:, A GPR-SLICE Workshop at the Dept of Geology, University of Georgia
- Athens and sponsored by the Student Association of Archaeological Sciences has been
arranged by Sheldon Skaggs and his advisor Dr. Ervan Garrison. For more information
regarding this workshop, please visit the Upcoming Events page of the www.GPRSURVEY.com website for registration materials and contact Sheldon Skaggs
skaggs1@uga.edu to register.
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I will be working in Japan from November 19-December 23rd. Our laboratory has been
invited to work on several exciting projects, one of which includes a survey of an
Imperial Family burial mound located in the city of Osaka. This will be a the first time
ever that a GPR research contract was awarded by the Imperial Family for investigating
a burial mound. Up until now the limited GPR surveys on Imperial Family tombs, which
had only ever been done at the Saitobaru Burial Mounds, was relegated to research
only. It is a great honor for us to have received the primary permission to do this
survey. During the travels in Japan, I will not be able to provide regular phone
assistance. I will be able to answer any pressing email questions on a daily basis
however.
This newsletter is available in a word document on the Subscribers Only page of the
www.GPR-SURVEY.com website.
best wishes, Dean
GPR_Slice V5.0 www.gpr-survey.com
Figure 1. Example of radargram displays using the new Open GL 3D Radar menu.
GPR_Slice V5.0 www.gpr-survey.com
Figure 2. Example of a GPS radargram display using the new Open GL Radar menu.
GPR_Slice V5.0 www.gpr-survey.com
Figure 3. Example of a radargram display and 3D time slices fence display available in
the new Open GL Volume menu.
GPR_Slice V5.0 www.gpr-survey.com
Figure 4. A screen shot of the GPS Track menu and Edit Info File menu showing the
location of the newly engaged GSS to UTM button.
GPR_Slice V5.0 www.gpr-survey.com
Figure 5. A screen shot of the Static menu shows the location where multiple horizon
surface designations are entered.
GPR_Slice V5.0 www.gpr-survey.com
Figure 6. Example of an Open GL Volume display with radargrams, 3D fences, and a
horizon surface.
GPR_Slice V5.0 www.gpr-survey.com