Time-domain optical coherence tomography system based on stationary wavelet transform

Based on the balanced detection and stationary wavelet transform (SWT) algorithm, a broadband low coherent white light source with center wavelength of 700 nm was employed to set up a time-domain optical coherence tomography (TDOCT) system in free space. The resolution of the developed OCT system was down to 0.93 m and it was applied to nondestructive evaluation of plastic sheets and transparent-tape multi-layered thin-film structures.The imaging enhancement methods in the process of OCT images were compared. To resolve the problem of unsatisfactory reconstruction results using current algorithms, the SWT decomposition algorithm was introduced to deal with the OCT images of the multi-layered structures. The experimental results show that this SWT-based method could extract more distinct interface interference signal from the SWT detail coefficients and therefore the interface imaging quality of multi-layered structures could be enhanced.