Precision optical displacement measurement system

摘要

Apparatus and method for measuring the relative distance between different areas on a remote surface or displacements of a selected area of a remote surface with respect to a measuring apparatus are provided. A laser beam is modulated at an RF frequency and focused on a selected area. The selected area is scanned by movement of a mirror and at each selected area the phase difference is measured. Digital data processing of signals derived from the source and return beams is used to provide high precision. For detecting or measuring vibration or displacement, an analog signal is obtained from a low-pass filter.