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.

fficient, window, and region based activity level measurement (CAM, WAM, RAM), choose-max (CM), optimization based method (OP), weighted-average, and substitution based coeff
icients combining (WACC, SCC), window and region based consistency verification (WRCV), cross-scale fusion rule (CSF), guided filtering based weighted average (GFWA), etc.

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
fficients combining (CM-WACC), substitution of sparse coeffi
cients (SSC), spatial context based weighted average(SCWA), etc.

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.

cient and window based activity level measurement (CWAM), CM-WACC, CS, integration of component substitution and weighted average (ICSWA), etc.