Dust polarization studies on MHD simulations of molecular clouds: comparison of methods for the relative-orientation analysis

Context. Polarized dust emission can be used as a probe for magnetic fields at different scales. In particular, the analysis of relative orientation between density structures and field projected on plane sky provide information role in shaping structure molecular clouds. Aims. The has been investigated using methods. Our goal is to explicitly compare two them: Rolling Hough Transform (RHT) gradient technique. Methods. We have applied RHT method technique regions, identified surface brightness maps 353 GHz generated via MHD simulations post-processed radiative transfer modelling. For both methods we derived structures, which statistics, histogram (HRO) statistic Rayleigh (PRS). Results. samples pixels selected by each are substantially different. When same pixel selection, results terms function column consistent other. its own differences apparent. Region 1, roughly reproduces observed trend becoming more perpendicular increasing density, while method, resolution RHT, gives opposite trend, with moving towards parallel alignment. 2, situation reversed. inconsistent results, due selections operated intrinsic them, complementary valuable information. Abridged.