917 research outputs found
Learning-based superresolution land cover mapping
Super-resolution mapping (SRM) is a technique for generating a fine spatial resolution land cover map from coarse spatial resolution fraction images estimated by soft classification. The prior model used to describe the fine spatial resolution land cover pattern is a key issue in SRM. Here, a novel learning based SRM algorithm, whose prior model is learned from other available fine spatial resolution land cover maps, is proposed. The approach is based on the assumption that the spatial arrangement of the land cover components for mixed pixel patches with similar fractions is often similar. The proposed SRM algorithm produces a learning database that includes a large number of patch pairs for which there is a fine and coarse spatial resolution representation for the same area. From the learning database, patch pairs that have similar coarse spatial resolution patches as those in input fraction images are selected. Fine spatial resolution patches in these selected patch pairs are then used to estimate the latent fine spatial resolution land cover map, by solving an optimization problem. The approach is illustrated by comparison against state-of-the-art SRM methods using land cover map subsets generated from the USA’s National Land Cover Database. Results show that the proposed SRM algorithm better maintains the spatial pattern of land covers for a range of different landscapes. The proposed SRM algorithm has the highest overall accuracy and Kappa values in all these SRM algorithms, by using the entire maps in the accuracy assessment
Deep Learning for Reversible Steganography: Principles and Insights
Deep-learning\textendash{centric} reversible steganography has emerged as a
promising research paradigm. A direct way of applying deep learning to
reversible steganography is to construct a pair of encoder and decoder, whose
parameters are trained jointly, thereby learning the steganographic system as a
whole. This end-to-end framework, however, falls short of the reversibility
requirement because it is difficult for this kind of monolithic system, as a
black box, to create or duplicate intricate reversible mechanisms. In response
to this issue, a recent approach is to carve up the steganographic system and
work on modules independently. In particular, neural networks are deployed in
an analytics module to learn the data distribution, while an established
mechanism is called upon to handle the remaining tasks. In this paper, we
investigate the modular framework and deploy deep neural networks in a
reversible steganographic scheme referred to as prediction-error modulation, in
which an analytics module serves the purpose of pixel intensity prediction. The
primary focus of this study is on deep-learning\textendash{based} context-aware
pixel intensity prediction. We address the unsolved issues reported in related
literature, including the impact of pixel initialisation on prediction accuracy
and the influence of uncertainty propagation in dual-layer embedding.
Furthermore, we establish a connection between context-aware pixel intensity
prediction and low-level computer vision and analyse the performance of several
advanced neural networks
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