Reconstruction results of source Cassiopeia A from the RMS-Clean algorithm. Top left: reconstructed model image. Top right: model error image, which is the difference between the reference model image and the reconstructed model image. Bottom left: residual image. Bottom right: restored image, which is the sum of the reconstructed model image convolved with the CLEAN beam and the final residuals. The specified scale list is [0, 7, 15, 22, 30] pixels that are randomly perturbed during the RMS-Clean deconvolution. The specified scale list can also be written as the relation between a scale list and the PSF main lobe, which has more physical meaning. For example, [0, 7, 15, 22, 30] pixels = [0, 3.3, 10.5, 14.3] × 2.1 pixels for this experiment. However, these two representations are completely equivalent because the PSF main lobe is a constant for a given experiment and only a common factor is extracted for the second representation.