Methods | Transforms | Fusion strategies |
Multi-scale decomposition | pyramid, wavelet, complex wavelet, curvelet, contourlet, shearlet, ripplet, edge-preserving decompositions, anisotropic heat diffusion, log-Gabor transform, support value transform, optimal scale transform, etc. | coe |
Sparse representation (SR) | orthogonal matching pursuit, group SR, gradient constrained SR, simultaneous OMP (SOMP), joint sparsity model, SR with over-complete dictionary, structural sub-dictionary, spectral and spatial details dictionary, etc. | WAM, choose-max and weighted average based coe |
Methods in other domains | spatial domain (non-transforms), hue saturation-intensity transform (HSI), principal component analysis (PCA), Gram-Schmidt (GS) transform, matting decomposition, independent component analysis (ICA), gradient domain, and fuzzy theory, etc. | machine learning based weighted average (MLWA), block and region based activity level measurement (BRAM), SCWA, model based method (MM), component substitution (CS), etc. |
Combination of different transforms | hybrid wavelet-contourlet, multi-scale transform-SR, morphological component analysis-SR, contourlet-SR, IHS-retina inspired models, IHS-wavelet, etc. | coeffi |