Small-sized visual angular displacement measurement technology

Abstract

Visual angular displacement measurement methods are a popular approach to photoelectric displacement measurement technology, as they provide significantly higher precision than traditional angular displacement measurement methods. This paper proposes a small-sized high-precision angular displacement measurement technology based on the sub-pixel level varying principle. The small-sized visual angular displacement measurement mechanism is first established without lens near-field imaging. A coding method based on the varying principle is then developed in order to decrease the ruled grating density. A sub-pixel angular displacement calculating model based on uniline pix is built to decrease the pixel data and enhance the frequency response of the measurement system; the corresponding data combination and correction algorithms are proposed. The error analysis is proposed. Tests on an angular displacement measurement device prototype showed a resolution of 20-bit and precision of 20.4″. The device also outperformed traditional angular displacement measuring devices of similar size, but features low ruled grating density and miniaturization. The results presented here may thus provide a workable foundation for further research on small-size visual angular displacement measurement devices.