An illumination-dependent adaptive fusion method for infrared and visible images

•An adaptive fusion method that can be adjusted according to illumination conditions is proposed.•An illumination-dependent and non-linear function-based fusion rule is designed to combine small-scale detail layers.•An illumination-dependent and WLS optimization-based fusion rule is proposed to combine large-scale detail layers.•A new WLS optimization-based rule is proposed to combine base layers.•The proposed method can adaptively fuse useful information under different illumination conditions.