In this work we develop a partially-coherent spirally-polarized imaging system for generating gradual edge detection images. A rotating diffuser is used for producing illumination sources with tunable degree of coherence. Using a 4f configuration, the frequency content of the image is modified by means of a vortex half-wave retarder as a spatial filter. Accordingly, we analytically describe a spirally-polarized imaging system illuminated with a Gauss-Schell source using paraxial coherence-polarization theory. Numerical simulations and experimental results demonstrate the validity of our approach. We use a referenceless spatial content descriptor to assess the quality of the recorded images as a function of the coherence state of the source.