Correction of measured position changes in optical probe-based measurement using palm/finger print image matching technique

Palm and finger are usually preferred to be used as measured sites in optical probe-based measurement because they both are convenient and easy to be measured at any time. However, measured position changes induced by artificial movement could influence the detected light due to the inhomogeneity of skin tissue structures beneath different measured sites. In this paper, our aim is to present an efficient method to correct measured position changes by using palm/finger print image matching technique. This image matching technique combined wavelet transform with phase correlation and paraboloid surface fit. During the measurement, optical probe was driven to the fixed position based on the translation and rotation changes between different measured positions calculated by the proposed technique. The results show that for the noise-free palm/finger print images, the matching accuracy is less than 1/50 pixel for translation and 0.15° for rotation. Finally, spectroscopic measurement results show that spectral stability with current palm/finger print image matching technique increases by around three times more than that without the technique.