Influence of relativistic effects on the PA and the emission angle. The rotation of the PA (a sum of the GR and SR effects) χ^tot (upper panels) and the emission angle ζ′ (lower panels) computed at r = r_ISCO (given in the upper left corner of each panel) for spins a = 0.2 (left panels), 0.5 (middle panels), and 0.8 (right panels) at three inclinations i = 30° (red), 60° (green), and 80° (blue lines). The results using ARTPOL code are shown with the solid lines, while the results from the ray-tracing in Kerr metric are presented with the dashed lines. The difference between the two values is shown under each panel.