Psychovision have shown that many grouping laws come into play to structure human vision. They use informations of different kinds, not only gray (or color)-level values. Here we will show how an orientation interpolation operator working in S1 (angle in [0, 2[) can be used to recover geometrical information in images. The operator is presented and is used to produce fields that drive a Fast Marching contour extraction algorithm and a LIC-based smoothing method. Experiment on real images are reported to validate the proposed approach.