Measurement of micro-harmonic vibration from optical feedback interferometry using wavelet trend analysis.

Area of Science:

• Optical sensing
• Signal processing
• Vibration analysis

Background:

• Self-mixed (SM) optical feedback interferometry is promising for vibration frequency measurement.
• Existing methods for extracting vibration data from SM signals require improvements in complexity and accuracy.

Purpose of the Study:

• To develop a novel, accurate, and less complex method for vibration frequency measurement.
• To address the limitations of current techniques in analyzing self-mixed laser signals.

Main Methods:

• Utilized maximal overlap discrete wavelet transformation (MODWT) and multi-resolution analysis (MRA).
• Applied the method to reconstruct micro-harmonic vibrations and measure vibration frequencies under varying feedback conditions.

Main Results:

• Successfully reconstructed micro-harmonic vibrations up to 1 kHz with low error (MSE < 1.89, Max Rel Error < 8.79%).
• Measured vibration frequencies up to 10 kHz with high accuracy (±0.0001).
• Demonstrated suitability for non-sinusoidal vibration measurement under moderate feedback.

Conclusions:

• The proposed MODWT and MRA method offers an improved approach for vibration frequency measurement.
• This technique provides a compact, non-contact, and cost-effective alternative for applications like fault detection and medical diagnostics.