Comparison of angular diameters (Θ_LD). The x axis represents Θ_LD directly measured using LBI (Pietrzyński et al. 2019; Salsi et al. 2020, 2021), while the y axis shows angular diameters estimated using the relation proposed in this study (S​_V = (1.230 ± 0.021)(V − K_s)₀ + (2.845 ± 0.048)). The shaded blue area indicates a deviation range of ±3%. The bottom panel displays the relative differences between the SBCR-derived angular diameters and the interferometric angular diameters. The colors of the squares represent the distances of target (derived from parallaxes of HIPPARCOS; van Leeuwen 2007). Darker colors correspond to the larger distances.