| Version | Summary | Created by | Modification | Content Size | Created at | Operation |
|---|---|---|---|---|---|---|
| 1 | Sirius Huang | -- | 4920 | 2022-11-24 01:42:13 |
The convolutional sparse coding paradigm is an extension of the global Sparse Coding model, in which a redundant dictionary is modeled as a concatenation of circulant matrices. While the global sparsity constraint describes signal [math]\displaystyle{ \mathbf{x}\in \mathbb{R}^{N} }[/math] as a linear combination of a few atoms in the redundant dictionary [math]\displaystyle{ \mathbf{D}\in\mathbb{R}^{N\times M}, M\gg N }[/math], usually expressed as [math]\displaystyle{ \mathbf{x}=\mathbf{D}\mathbf{\Gamma} }[/math] for a sparse vector [math]\displaystyle{ \mathbf{\Gamma}\in \mathbb{R}^{M} }[/math], the alternative dictionary structure adopted by the Convolutional Sparse Coding model allows the sparsity prior to be applied locally instead of globally: independent patches of [math]\displaystyle{ \mathbf{x} }[/math] are generated by "local" dictionaries operating over stripes of [math]\displaystyle{ \mathbf{\Gamma} }[/math]. The local sparsity constraint allows stronger uniqueness and stability conditions than the global sparsity prior, and has shown to be a versatile tool for inverse problems in fields such as Image Understanding and Computer Vision. Also, a recently proposed multi-layer extension of the model has shown conceptual benefits for more complex signal decompositions, as well as a tight connection the Convolutional Neural Networks model, allowing a deeper understanding of how the latter operates.