After entering the 21st century,with the rapid improvement of computer processing capabilities,3D digital image correlation(3D-DIC)based on high-speed cameras has gradually been applied to various scientific research and engineering fields.Its advantages are that it can provide full-field vibration measurement and has relatively low requirements for the measurement environment.However,in terms of time sampling rate and measurement resolution,it cannot meet the general requirements of vibration measurement.Another mature vibration measurement method is the laser Doppler vibrometry(LDV)based on single-pixel photodetectors.This type of interference-based measurement technique has an extremely high time sampling rate and measurement resolution,and the requirements for isolation are also not high.But the main problem is that in the spatial domain,it can only achieve single-point or sparse-point measurement.For stationary vibration,although scanning can be used,the scanning range is limited due to the optical depth of field of the equipment,resulting in low spatial sampling rate.This paper proposes a new vibration measurement method,namely LDV-assisted full-field vibration measurements by 3D-DIC.By utilizing the advantages of the two methods in measurement resolution and full-field measurement,the vibration measurement resolution of full-field DIC can be improved to the 10-6～10-7 scale of characteristic size in both hardware and data processing aspects.Even without using a high-speed camera and vibration isolation measures,it is still possible to achieve interferometric-level full-field vibration measurement,which meets the requirements of most structural vibration measurements.
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