Surface brightness-color relation for eclipsing binaries with ubvy photometry

The relation between visual surface brightness and (b - y)(0) color index i s constructed for eclipsing binaries with Hipparcos parallaxes and photomet ry in the Stromgren four-color ubvy system. The relation is consistent with the Popper relation derived for stars with angular diameters obtained main ly from interferometry or from the lunar occultation method. It is shown th at the Lutz-Kelker correction to magnitudes is in this case negligible.