We apply the improved technique of Stokes polarimetry to measure the ellipticity form factor of the transmitted light in cholesteric liquid crystal (CLC) cells of wedge geometries at different polarizations of the incident wave. In the wedge geometry, a spatially varying local CLC pitch and the cell thickness are found to complicate the structure of the polarization parameter fields. We show available polarization singularities: C-point and L-lines on the light field after CLC. We also find periodic appear polarization singularities in Grandjean zones.