Comparison of the measured SPF (blue bars) with the theoretical SPF predicted by the Mie/DHS theory for a dust composition and size distribution best matching the observations (red curve). The three black curves show the SPF predicted by the Hapke theory with the assumptions of regolith particles for three different grain sizes from Min et al. (2010), described as micro-asteroids by these authors. The uncertainty is given at a 3σ level.