Читать книгу Change Detection and Image Time Series Analysis 2 - Группа авторов - Страница 20

The aforementioned stages lead to the computation of the posterior marginal on every site s of the second quad-tree. In principle, site s could directly be given the label i.e. the label that maximizes over the set Ω of classes. However, this strategy is often avoided in the literature of hierarchical MRFs because of its computational burden and of the risk of blocky artifacts (Laferté et al. 2000; Voisin et al. 2014). As an alternative, the case-specific formulation of the modified Metropolis dynamics (MMD) algorithm (Berthod et al. 1996), which was combined with MPM in Hedhli et al. (2016) for the case of multitemporal single-sensor classification, is generalized here to the multisensor case. We refer the reader to Hedhli et al. (2016) for more detail. In the case of both proposed methods, after this integrated MPM–MMD labeling, the classification result on the leaves of the second quad-tree provides the output classification map at the finest of the observed resolutions.