Roll angle measurement method based on a double-sided optical wedge

The roll angle is an important albeit difficult-to-measure geometric parameter. This study proposes a roll angle measurement method for an entire circle (360°). An elaborately designed double-sided optical wedge (DOW) is employed as a roll angle probe to divide the incident light beam into two beams. Both beams are imaged using a photodetector, and the roll angle of the DOW is obtained through the detection of the motion trajectories of the two images. The measurement principle is comprehensively analyzed, and the experimental results indicate that the accuracy of the constructed measurement system is better than ±7.72<i>a</i> <i>r</i> <i>c</i> <i>s</i> <i>e</i> <i>c</i> in the range of 360°. The proposed method is confirmed to be effective for large-range roll angle measurements.