Powerful Data Analysis Routine Helps Locate Buried Bombs
By Christian Barthel, Vice President, Barthel & Schreiber GmbH, Duisburg, Germany Ralf Rosenberger, ADDITIVE Soft- und Hardware für Technik und Wissenschaft GmbH, Friedrichsdort, Germany. May 1999.
Page 2: Execution speed
Barthel & Schreiber concluded that they could obtain the needed execution speed by programming the algorithms in the C or C++ programming language and compiling the result as a Dynamic Linked Library (DLL) file, which would enable it to be called by third-party applications. They discovered a data analysis program, Origin, that can be linked to an external DLL, has the ability to create a custom user interface, and can also be custom programmed. They hired Additive, a German firm with considerable experience in customizing Origin, to link the data analysis program to the proprietary algorithms, a process that took only a few weeks.
The LabTalk program begins by importing the magnetic sensor readings for each GPS coordinate covered by the survey. It then converts the GPS matrix into absolute coordinates.
The LabTalk program developed by Additive begins by importing the magnetic sensor readings for each GPS coordinate covered by the survey. The LabTalk program then converts the GPS matrix into absolute coordinates. This transformation involves two separate steps: first transforming the individual coordinates, then rotating the coordinate system in order to align its axes with the rectangular area that was the subject of the survey. This area is almost never normal to GPS coordinates because of geographical obstructions such as rivers and roads. In some cases, data is missing from certain sections and this data is replaced using Origin interpolation features.
Next, the LabTalk routine interrogates the matrix using the proprietary data analysis routines developed by Barthel & Schreiber. Additive engineers code these routines into a DLL and call the routines from the LabTalk script. The routines use recursive algorithms that check the magnitude and extent of the magnetic field, convert the data to a pattern curve, then access a nonlinear curve fitter that attempts to fit the data to a library of signatures generated by known explosive objects. The script accesses Origin to set up the matrix, makes a call to the DLL, reads the results of the algorithm and annotates the graphs used to present the data. The LabTalk language is interpreted but runs extremely fast because the script calls the compiled Origin program to run all of the calculation-intensive code. Testing has shown that the code is nearly infallible in detecting bombs and although it does have a certain percentage of false positives. The program concludes by plotting the suspect bombs on top of the area that has been surveyed at a scale of 1 to 50 on A0 paper, which is nearly one meter high by one meter wide. In the final step of the survey, a trained analyst visually examines the plot and determines which of the detected items actually need to be removed.
This program is now in use at the half a dozen or so projects that Barthel & Schreiber operates at any given time. The largest current project is an airfield near Munster that currently occupies 20 of the firm's employees. It was a German airbase in World War II, served as a British airbase after the war, and was recently returned to Germany for use as a civilian airport. The airport is being expanded and this requires construction in areas that were heavily bombed during the war. It will take about one year to clear the entire area involved, which is about 1 hectare. At the midway point in the project, the company has already found several bombs, including a 500-pound bomb that was the largest it had ever found. Barthel & Schreiber's executives believe that their ability to process data faster and more accurately than other firms in their business is a key competitive advantage. In particular, they point to their ability to code new data analysis ideas in just a day or two using the friendly, but powerful, LabTalk language built into Origin.
For more information on Origin contact OriginLab Corporation, One Roundhouse Plaza, Northampton, MA 01060. Phone: 800-969-7720 X36. Fax: 413-585-0126.