Squared visibility vs. spatial frequency for HD 2665 and HD 6755. The HD number is noted in the right upper corner in the each plot. The error bars have been scaled to the reduced χ². For HD 2665 the reduced χ² = 1.6 and for HD 6755 χ² = 1.7. The grey dots are the individual PAVO measurements in each wavelength channel. For clarity, we show weighted averages of the PAVO measurements as red circles. The green line shows the fitted limb-darkened model to the PAVO data, with the light grey-shaded region indicating the 1-σ uncertainties. The lower panel shows the residuals from the fit.