Forward Looking Mine Detection with Laser Doppler Vibrometers

This Phase II proposal is for developing a whole-field digital laser vibrometer (WDV) system capable of detecting buried landmines from a moving platform. Experiments have shown the feasibility of this technique to measure ground surface profiles aboveburied objects. We anticipate that the proposed system will be capable of detecting the presence of landmines at a rate of 1 m2 in tens of milliseconds. Furthermore, the proposed WDV would not be affected by the Doppler shift due to the platform motion. Adual pulse laser system would allow optimizing the signal as a function of acoustic excitation frequency. An innovative speckle reposition strategy would allow movement of the measurement platform at high speeds while still obtaining measurements withprecise interferometric resolution. To date, laser-acoustic systems have been successfully demonstrated with a stop and scan technique and mainly in a downward-looking configuration. The proposed WDV would help to overcome both of these limitationsenabling a practical system for either direct or confirmatory measurements. The Phase II work will consist of experimental work, design, and construction of a prototype system and fieldwork to demonstrate the developed system in a landmine field.Theproposed system will be capable of measuring surface vibration from a platform moving at several m/s. This system, upon development, will provide inspectors with a powerful tool for safely detecting the presence of landmines. These concepts also have wideapplication in the area of non-destructive inspection for the automotive, aerospace, machinery, and construction industries.