Further improvement of edge location accuracy of double fiber spherical coupling sensor using orthogonal Jacobi–Fourier moments

In order to further improve the edge location accuracy of double fiber spherical coupling sensor, an approach based on OJFMs is proposed. In this paper, OJFMs with high order spatial moment and simple calculation is built. Then, its edge location method and fast discrete algorithm is proposed. Finally, the proposed method is tested by locating the edge of standard pattern and the image acquired by double fiber spherical coupling sensor with lot of noise. Experiment results show that the location accuracy is up to 0.05 pixel and 0.08 pixel for standard lines and standard circle, respectively. The accuracy of double fiber spherical coupling sensor is 0.026 pixel in 2σ band and a actual accuracy of 36 nm is obtained by OJFMs after a moving average filter (N = 7).