A laser Doppler vibrometer featured with the in-housed mechanism for adaptive compensation of body vibration

We present a novel and economic means to cope with the problem of laser Doppler vibrometer (LDV) body vibration in the longitudinal direction of the measurement. The suggested approach does not require any external reference surface. Instead, a damper is fabricated and compactly housed in the LDV, and the LDV's body movement is indirectly inferred by adaptively processing the beam reflected from the in-housed damper. Utilization of the in-housed damper and the adaptive signal processing significantly alleviate the problem of calibration and environmental settings. It is also shown that the slowly varying statistics of the environmental vibration, the assumption of which can be justified in most of practical situations, can be effectively exploited and removed from the measured signal by applying an LMS adaptive algorithm.