Pattern speed for a toy model in the image domain (shown in warm tones, with color denoting mean brightness at the angular radius, or impact parameter, marked by the top x-axis) and in the (u, v) domain (cool tones, with color denoting mean amplitude for a given ρ marked by the bottom x-axis). The image-domain values are measured from an analytic iNoisy model with a known power-law dependence. The best-fit curve to the (u, v) pattern speed (blue) asymptotically approaches the brightness-weighted image-domain pattern speed (dashed purple).