High-precision dynamic measurement of roll angle based on digital holography

Abstract

Among the six degrees of freedom for a moving body, measuring roll angle is the most difficult. In this study, a noncontact, no-imaging dynamic roll angle measurement system based on holography is proposed. Two beams of light are used to irradiate the measured object symmetrically, then two reflected light and the reference light interfere with each other to produce a hologram. By extracting the phase information of the two reflected light from two illumination beams using single hologram, this method achieves dynamic measurement of in-plane deformation, and then the roll angle is obtained through subsequent data processing. The effectiveness of the proposed method in-plane roll angle measurement is validated based on theoretical and experimental results. Experimental results show that the proposed method measures roll angle with high accuracy at both fixed and varied distances.