Joint polarization-color coding strategy based on Stokes parameter for robust strip-edge detection in 3D measurement

Stripe-edge detection of color fringe is crucial in structured light measurement. However, the robustness of color stripe-edge detection is affected by the color crosstalk, scattering, and the color filter in the color camera. This can lead to a decrease in imaging quality. In order to avoid the influence of color crosstalk, this paper analyzes the polarization properties of RGB channels and proposes a joint polarization-color coding strategy based on the Stokes parameter and a corresponding stripe-edge detection method. Compared with the traditional color-coded fringe measurement system, the monochrome camera can distinguish the color-coded fringe so that the influence induced by color crosstalk is eliminated completely. Furthermore, the influence induced by the scattering is reduced. The experiment shows that the robustness of strip-edge detection is remarkably improved, the nonparallelism of detected edges reduced by 32.4%, and the nonuniformity of detected edges reduced by 44.1%.