Extremely Shallow Underground Imaging Using Scanning Laser Doppler Vibrometer

Ground penetrating radar (GPR) and elastic wave exploration have been widely used in underground exploration. However, it has not been possible to explore extremely shallow underground areas up to 10 cm below the ground surface, because various waves are received and the reflected wave cannot be separated. Although land mines have become a serious problem all over the world, the existing detection methods are not very effective in the case of soil containing electrolytes, for example, laterite soil in Southeast Asia. Therefore, we propose a method using a sound wave and a scanning laser Doppler vibrometer (SLDV). We conducted an exploration experiment of buried objects both in the laboratory and outdoors. As a result, the frequency responses of the buried objects were obtained and the responses of the buried objects were confirmed by imaging. Therefore, it is possible to use this method at an actual site.