Ground radar users have long known that to get the best results, the aerial must be perpendicular to a row of trees. But thanks to Delft research, they now understand why.
/strong>
While preparing a site for building, ground radar is used to trace the precise course of sewers. It’s also suitable for more exiting tracking, like searching for buried historical treasures, contaminated soil, mines, and even corpses, that are buried up to ten meters underground. Today, Delft electronic engineer Jan van der Kruk, will receive his PhD for developing an algorithm to improve the quality of the ground image.
In the past, acoustics were used to search the subsoil without a scoop or excavator. Sound waves, penetrating miles into the ground, could detect gas and oil fields. But acoustics didn’t provide an image of the first few meters beneath one’s feet. For that, ground radar has been available since the 1980s.
The creation of an image of the present ground radar is evidently based on the seismograph. The reflections of radar signals are translated into an image as if they were sonic waves. Sound is a scalary wave, and radar is a vectorially wave. Radar waves look like waves at the beach, the strength height) is perpendicular to the direction of propagation. With sound, the amplitude is parallel with this direction.
“Radar radiation is electromagnetic radiation and therefore a vector,” Van der Kruk explains. “Using the signals that way – which my algorithm does % usually gives you a clearer image of the ground. That’s because you’re better able to take the direction dependence into account.”
Besides providing an improved image, ‘vector thinking’ improves understanding. Van der Kruk: “A row of trees disturbs the ground radar measurements. But turning around the equipment seems to help. With the seismic method these aboveground reflections aren’t explainable, but using the vectors they are, including the influence of turning the equipment around. By positioning the aerial perpendicular to the row of trees, you minimalise reflections. When I told stated this at a symposium, I noticed the people suddenly understood the whole thing.”
Van der Kruk doesn’t dare to estimate the image quality improvement in plain numbers. “We buried several objects in a big sandbox. We scanned the box with ground radar and made images using several algorithms. Applying my new algorithm, the objects are better detectable: there’s a bigger contrast with the background and the edges are sharper – in most cases, that is.”
Until now, Van der Kruk’s algorithm has remained buried in a computer. His research group is considering whether to grant his wish of publishing a user-friendly version on the Internet or cd-rom.
Ground radar users have long known that to get the best results, the aerial must be perpendicular to a row of trees. But thanks to Delft research, they now understand why.
While preparing a site for building, ground radar is used to trace the precise course of sewers. It’s also suitable for more exiting tracking, like searching for buried historical treasures, contaminated soil, mines, and even corpses, that are buried up to ten meters underground. Today, Delft electronic engineer Jan van der Kruk, will receive his PhD for developing an algorithm to improve the quality of the ground image.
In the past, acoustics were used to search the subsoil without a scoop or excavator. Sound waves, penetrating miles into the ground, could detect gas and oil fields. But acoustics didn’t provide an image of the first few meters beneath one’s feet. For that, ground radar has been available since the 1980s.
The creation of an image of the present ground radar is evidently based on the seismograph. The reflections of radar signals are translated into an image as if they were sonic waves. Sound is a scalary wave, and radar is a vectorially wave. Radar waves look like waves at the beach, the strength height) is perpendicular to the direction of propagation. With sound, the amplitude is parallel with this direction.
“Radar radiation is electromagnetic radiation and therefore a vector,” Van der Kruk explains. “Using the signals that way – which my algorithm does % usually gives you a clearer image of the ground. That’s because you’re better able to take the direction dependence into account.”
Besides providing an improved image, ‘vector thinking’ improves understanding. Van der Kruk: “A row of trees disturbs the ground radar measurements. But turning around the equipment seems to help. With the seismic method these aboveground reflections aren’t explainable, but using the vectors they are, including the influence of turning the equipment around. By positioning the aerial perpendicular to the row of trees, you minimalise reflections. When I told stated this at a symposium, I noticed the people suddenly understood the whole thing.”
Van der Kruk doesn’t dare to estimate the image quality improvement in plain numbers. “We buried several objects in a big sandbox. We scanned the box with ground radar and made images using several algorithms. Applying my new algorithm, the objects are better detectable: there’s a bigger contrast with the background and the edges are sharper – in most cases, that is.”
Until now, Van der Kruk’s algorithm has remained buried in a computer. His research group is considering whether to grant his wish of publishing a user-friendly version on the Internet or cd-rom.
Comments are closed.