CDF-DSR: Learning continuous depth field for self-supervised RGB-guided depth map super resolution

RGB-guided depth map super-resolution (GDSR) is a pivotal multimodal fusion task aimed at enhancing low-resolution (LR) depth maps using corresponding high-resolution (HR) RGB images as guidance. Existing approaches largely rely on supervised deep learning techniques, which are often hampered by limited generalization capabilities due to the challenges in collecting varied RGB-D datasets. To address this, we introduce a novel self-supervised paradigm that achieves depth map super-resolution utilizing just a single RGB-D sample, without any additional training data. Considering that scene depths are typically continuous, the proposed method conceptualizes the GDSR task as reconstructing a continuous depth field for each RGB-D sample. The depth field is represented as a neural network-based mapping from image coordinates to depth values, and optimized by leveraging the available HR RGB image and the LR depth map. Meanwhile, a novel cross-modal geometric consistency loss is proposed to enhance the detail accuracy of the depth field. Experimental results across multiple datasets demonstrate that the proposed method offers superior generalization compared to state-of-the-art GDSR methods and shows remarkable performance in practical applications. The test code is available at: https://github.com/zsy950116/CDF-DSR.