Fig. 4.

(a) Orthogonal $\theta$ (blue) and $\phi$ (red) equiangular scans along two stainless steel spheres with radii $r_1=8$ and $r_2=12.7\mathrm{m}\mathrm{m}$ are shown. The surface profiles along the (b) $\theta$ and (c) $\phi$ directions are plotted; the maximum deviation with respect to a baseline measurement obtained at $\left(\theta =\phi =0^{\circ }\right)$ was approximately 15 μm.