Effects of disk substructures on the mass underestimation. Left column: representative 1.3 mm dust continuum image for each scenario of disk substructures. The raw radiative transfer images are convolved with a Gaussian beam of 35 mas in size (~ 5 AU at the distance of 140 pc, indicated with the filled white circle in the lower left corner of each image). The disk is seen face-on merely for a better presentation of the disk configuration. Middle column: 1.3 mm flux density (F_{1.3 mm}) and mass-averaged temperature (T_dust) as a function of total dust mass (M_dust). When we simulated the SED, the fiducial inclination of 41.8° was adopted. Right column: underestimation factor as a function of M_dust. The green filled circles refer to the underestimation factors for smooth disks that have an equivalent R_out to that of the disks with substructures; see Sect. 3.5.