Low-coherence interferometry based on continuous wavelet transform

The present paper proposes a low-coherence interferometry system based on continuous wavelet transform, which can simultaneously detect the peak position and frequency of a signal. Although the proposed system is analogous to conventional time-domain optical coherence tomography, it realizes accurate wide-range surface profile measurement because the wavelet transform enables accurate evaluation of the position of the reference mirror. The performance of the proposed system was evaluated through step-height measurement.