RSC-DGS: Fusion of RGB and NIR Images Using Robust Spectral Consistency and Dynamic Gradient Sparsity

Color (RGB) images captured under low light condition contain much noise with loss of textures. Since near-infrared (NIR) images are robust to noise with clear textures even in low light condition, they can be used to enhance low light RGB images by image fusion. In this paper, we propose fusion of RGB and NIR images using robust spectral consistency (RSC) and dynamic gradient sparsity (DGS), called RSC-DGS. We build the RSC model based on a robust error function to remove noise and preserve color/spectral consistency. We construct the DGS model based on vectorial total variation minimization that uses the NIR image as the reference image. The DGS model transfers clear textures of the NIR image to the fusion result and successfully preserves cross-channel interdependency of the RGB image. We use alternating direction method of multipliers (ADMM) for efficiency to solve the proposed RSC-DGS fusion. Experimental results confirm that the proposed method effectively preserves color/spectral consistency and textures in fusion results while successfully removing noise with high computational efficiency.