Histogram of the number of sources extracted per bin for the pre-processed input data of the test cases presented in Sect. 7. In the left panel, three observables are considered: the FLUX_AUTO in uiK_s. In the right panel, six observables are considered: the FLUX_AUTO in uiK_s and the FLUX_RADIUS in uiK_s. With the binning rule described in Sect. 3.5, between the “Multi-type” case and the “Fatrtening E” case, the number of bins increases by a factor 10³, and the number of empty bins is increased by roughly the same amount. This illustrates the curse of dimensionality we face in this method, and puts computational limits on the number of observables we can use.