Time-Frequency Analysis for Landmine Detection Using Impulse Ground Penetration Radar
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Date
2012-01
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Addis Ababa University
Abstract
Land mine detection is an important and yet challenging problem and one that remains to be
solved. Ground Penetrating Radar (GPR) is an effective sensor to detect land mines that are
made of plastic or have low metal content.
GPR operates by first transmitting an impulse signal down to the mine field, second receives the
signals reflected from the different layers of the ground and processes the received image to give
a revealing picture of the size and shape of a landmine (metal or plastic) and where exactly it is
located.
In electromagnetic wave propagation modeling, a multilayer transmission line technique is applied.
It considers different soil types and targets of different diameters which are buried at different
depths. Signal processing algorithms are implemented for clutter reduction. Preprocessing
techniques such as DC Offset removal, Antenna cross talk, Noise Reduction (using weighted
moving average and exponential moving average) and Background clutter reduction. GPR signal
processing algorithms apply processing in time domain; therefore an advanced signal processing
technique which is a 2D (time and frequency) view of a signal is required to see a more revealing
picture.
After preprocessing steps have been accomplished then further process with advanced signal
processing techniques to get a more revealing picture of the energy concentration of the buried
target at different time instants. Joint time-frequency transforms were developed for the purpose
of characterizing the time-varying frequency content of a signal. The best-known time-frequency
representation of a time signal dates back to Gabor and is known as the short-time Fourier transforms
(STFT). It is basically a moving window Fourier transforms. By examining the frequency
content of the signal as the time window is moved, a 2D time-frequency distribution called the
spectrogram is generated. The spectrogram contains information on the frequency content of the
signal at different time instances.
Considering a real GPR data [1] where target objects and non target objects or clutters which are
buried at different positions and after passing through Matlab algorithms, a more revealing picture
is created.
Keywords; land mine detection, GPR system, demining.
Description
Keywords
land mine detection, GPR system, Demining