Full-field laser heterodyne imaging vibrometry using a CMOS-DVR system

Area of Science:

• Optical Measurement
• Vibration Analysis
• Signal Processing

Background:

• Full-field vibration measurement is crucial for understanding structural dynamics.
• Existing methods like laser Doppler vibrometry have limitations in certain applications.
• Speckle noise can degrade the accuracy of optical vibration measurement techniques.

Purpose of the Study:

• To introduce and validate a novel laser heterodyne imaging vibrometry system.
• To develop a robust digital demodulation method for handling speckle noise.
• To compare the performance of the proposed method against established techniques.

Main Methods:

• Utilizing laser heterodyne imaging for vibration response acquisition.
• Employing a CMOS camera and digital video recorder for data capture.
• Implementing a digital demodulation algorithm based on cumulative distribution function and autocorrelation.

Main Results:

• The proposed laser heterodyne imaging vibrometry successfully performed full-field vibration measurements.
• The digital demodulation method effectively mitigated speckle noise.
• Experimental validation confirmed the method's viability and precision, comparable to laser Doppler vibrometry.

Conclusions:

• Laser heterodyne imaging vibrometry offers an effective and precise solution for full-field vibration measurement.
• The developed digital demodulation technique enhances measurement accuracy in the presence of speckle noise.
• This approach provides a valuable alternative for detailed vibration analysis in various scientific and engineering fields.