Table 1 Algorithmic module

The proposed algorithmic: Based on Nonlinear Enhancement and NSST Decomposition

Input: Infrared image IR, visible images VIS, parameter λ

Output: Fused image F

1. IR and VIS are decomposed into high- and low-frequency components by NSST.

2. The parameter λ set to 10; compute fusion weight C_IR and C_VIS by nonlinear function S(λ) (Eqs. 5–8).

3. Obtain fused low-frequency component LFC_F using LFC _ F = C_IR ∗ LFC_IR + C_VIS ∗ LFC_VIS.

4. Fuse high-frequency components using WT-based method with “mean” and “maximum absolute” rules to obtain fused high-frequency component HFC_F.

5. Repeat 4 until all corresponding components are fused.

6. The final fused images F is obtained by inverse NSST.