Reflection Intensity Guided Single Image Reflection Removal and Transmission Recovery

Single image reflection removal (SIRR) aims at eliminating unwanted interference caused by the reflection of transparent or smooth surfaces and obtaining an estimation of a clear transmission layer. Existing data-driven methods typically rely on decomposing the observed image into transmission and reflection layers, which neglects the physical generation principles of an image with reflections, thus leading to unsatisfactory results, especially in strong reflection regions. To address this issue, in this work, we analyze the imaging process of reflection image from the physical perspective and derive a conclusion that the physical quantity: illuminance of the reflection layer determines the reflection intensity. Then a two-stage reflection intensity-guided network (RINet) is proposed for reflection removal and transmission recovery. The key lies in the first stage are the parallel modules that generate the reflection intensity map and transmission layer. In the second stage, besides utilizing such intensity map as the guidance, we additionally calculate the gradient field as the other prior to facilitate the final reflection removal. Specifically, we design a dual-flow joint learning module (JLM) comprised of a transmission recovery branch and a gradient optimization branch that jointly optimizes image structures and details by exploiting the interactions between transmission and gradient features. In particular, guided by the reflection intensity map, the transmission recovery branch can dynamically focus on removing reflections. Equipped with the two-stage framework, our RINet constitutes a divide-and-conquer process to achieve effective transmission recovery and reflection removal. Experimental results on public datasets demonstrate the superiority of the proposed method over recent state-of-the-art methods.