Abstract: In this paper, a high-accuracy algorithm for the interpolated displacement of grating signal is presented which based on Lissajous figure. The key of the algorithm is to separate and correct the DC level drift, the orthogonal error and the amplitude error from imperfect grating signal. As a result, the accuracy of the interpolated displacement of grating measurement system can be raised. Experiments and comparisons have proved the fact that the algorithm is correct and effective.

Key words: Lissajous figure, interpolation, grating measurement system