Top: observed visibilities for ESO323-G77 as a function of spatial frequency along the position angle  ~38°. Visibility curves for Gaussian distributions with a HWHM/R_in of 20 (dotted) and 12 (dashed), and a power-law distribution with R_1/2/R_in = 7 (dash-dot) are over-plotted. Bottom: Gaussian HWHM (plus signs) and R_1/2 (filled circles) are plotted against the same spatial frequency. The red to green colors indicate the observing wavelengths in the rest frame from 13 to 8.5 μm. For a given wavelength, while the Gaussian HWHM is baseline-dependent, the half-light radius is approximately baseline-independent, thus seems adequate for representing the whole structure.