Neural radiance fields (NeRFs) have demonstrated remarkable performance in novel view synthesis. However, there is much room for restoring 3-D scenes based on NeRF from corrupted images, which are common in natural scene captures and can significantly impact the effectiveness of NeRF. This article introduces NeRF-MIR, a novel neural rendering approach specifically proposed for the restoration of masked images, demonstrating the potential of NeRF in this domain. Recognizing that randomly emitting rays to pixels in NeRF may not effectively learn intricate image textures, we propose a patch-based entropy for ray emitting (PERE) strategy to distribute emitted rays properly. This enables NeRF-MIR to fuse comprehensive information from images of different views. In addition, we introduce a progressively iterative restoration (PIRE) mechanism to restore the masked regions in a self-training process. Furthermore, we design a dynamically weighted loss function that automatically recalibrates the loss weights for masked regions. As existing datasets do not support NeRF-based masked image restoration, we construct three masked datasets to simulate corrupted scenarios. Extensive experiments on real data and constructed datasets demonstrate the superiority of NeRF-MIR over its counterparts in masked image restoration.

With the rapid growth of virtual human techniques and the popularity of 3D face modeling, multi-view face synthesis has received considerable attention in the computer vision community. Though learning-based methods have achieved photo-realistic effect, the lack of geometry guidance remains a great hurdle to their results in high fidelity of identity. To relieve it, we propose a novel network named Dual-Representation-Net (DR-Net) driven by both learning and geometry information. In addition, we utilize face parsing to lead the learning of regional attention, in this way, the two synthesizing representations can collaborate and compete dynamically under different face angles, which improves the stability of face synthesis by assimilating the benefits of both kinds of information. What is more, we want to emphasize that DR-Net can serve as a general framework for multi-view face synthesis by jointly exploiting learning and geometry information. That is, our geometry module and learning module are actually substitutable, which can be replaced by any other SOTA methods. This makes our method both flexible and scalable. Extensive experiments verify that our approach is superior to other counterparts in both synthesis quality and identity preservation. Moreover, with the geometric information, we can decouple the synthesis of face and background to obtain more robust results on in-the-wild data.

This paper presents the first unified distractor removal method, named IDDR-NGP, which directly operates on Instant-NPG. The method is able to remove a wide range of distractors in 3D scenes, such as snowflakes, confetti, defoliation and petals, whereas existing methods usually focus on a specific type of distractors. By incorporating implicit 3D representations with 2D detectors, we demonstrate that it is possible to efficiently restore 3D scenes from multiple corrupted images. We design the learned perceptual image patch similarity~( LPIPS) loss and the multi-view compensation loss (MVCL) to jointly optimize the rendering results of IDDR-NGP, which could aggregate information from multi-view corrupted images. All of them can be trained in an end-to-end manner to synthesize high-quality 3D scenes. To support the research on distractors removal in implicit 3D representations, we build a new benchmark dataset that consists of both synthetic and real-world distractors. To validate the effectiveness and robustness of IDDR-NGP, we provide a wide range of distractors with corresponding annotated labels added to both realistic and synthetic scenesExtensive experimental results demonstrate the effectiveness and robustness of IDDR-NGP in removing multiple types of distractors. In addition, our approach achieves results comparable with the existing SOTA desnow methods and is capable of accurately removing both realistic and synthetic distractors.

In this letter, a new full-wave inversion (FWI) scheme is proposed to reconstruct multiple dielectric parameters of 3-D arbitrary anisotropic objects buried in layered media. Three inverse solvers, including the isotropic one, biaxial anisotropic one, and the arbitrary anisotropic one, are cascaded sequentially. The dielectric parameters obtained by the first solver are used as the initial values of the next solver. Meanwhile, the inversion domain is synchronously downsized on the basis of discrepancies between the inverted dielectric parameters and the background ones. Numerical simulations show that, compared with the direct arbitrary anisotropic inverse solver, the cascading inversion scheme not only can produce more reliable reconstructed profiles but also significantly lowers the computational cost. In addition, the antinoise ability of the cascaded solvers is also tested.