Depth-image-based rendering (DIBR) technologies have been widely employed to synthesize novel realistic views from a single image in 3D video applications. However, DIBR-oriented approaches heavily rely on the accuracy of depth maps, usually requiring the depth GT as a prior. Despite that, there might exist extensive float precision losses and invalid holes in the synthesized view due to warping error and occlusion. In this paper, we propose an end-to-end as-deformable-as-possible (ADAP) single-image-based view synthesis solution without depth prior. It addresses the above issues through two stages: alignment and reconstruction, where we first transform the input image to the latent feature space and then reconstruct the novel view in the image domain. In the first stage, the input image is deformed to align with the synthesized view at feature level. To this end, we propose an ADAP alignment mechanism through pixel-level warping to error-level quantization to feature-level alignment, progressively improving the deformable capability in handling challenging motion conditions in real-world scenes. In the second stage, we exploit an occlusion-aware reconstruction module to recover the content details from the deformed feature at pixel level. Extensive experiments demonstrate that our alignment-reconstruction approach is robust to the depth map. Even with a coarsely estimated depth map, our solution outperforms other SoTA schemes in the popular benchmarks.

Recently, a pseudo-LiDAR point cloud extrapolation algorithm equipped with stereo cameras has been introduced, bridging the gap between the expensive 3D sensor LiDAR and relatively cheap 2D sensor camera in autonomous driving. In this paper, we explore an approach to further bridge this gap using only a monocular camera and extrapolate a wide field of view 3D point cloud from a limited 2D view. However, this task is extremely challenging as it requires inferring the occluded contents in the scene. To this end, we propose a ‘render-refine-iterate-fuse’ framework that takes advantage of both image view synthesis and image inpainting techniques, guiding the neural network to learn the potential spatial distribution. In addition, we design a hybrid rendering scheme to ensure that the visible content moves in a geometrically correct manner and fills the pixels caused by occlusion. Benefitting from the proposed framework, our approach achieves significant improvements on the pseudo-LiDAR point cloud extrapolation task. The gap between LiDAR and cameras is further bridged, showing an economical and practical application in the environment perception module of autonomous driving. The experimental results evaluated on the KITTI dataset demonstrate that our approach achieves superior quantitative and qualitative performance.

Single-image-based view synthesis is significant for generating a 3D scene and gains increasing attention in recent years. However, this task is challenging as it requires inferring contents beyond what is immediately visible. Previous methods directly predict the unknown views using the convolutional neural networks, but the generated views suffer from visually unpleasant holes, deformations, and artifacts. In this paper, we propose a Single-image-based view synthesis transformer (named SivsFormer) for high-quality and realistic view synthesis. In particular, a warping and occlusion handing module is designed to reduce the influence of parallax on the network. Subsequently, a disparity alignment module captures the long-range information over the scene and ensures that pixels move in a geometrically correct manner with soft probabilistic disparity maps. Moreover, we present a parallax-aware loss function to improve the quality of the synthetic images, which explicitly quantifies the magnitude of parallaxes. We conduct extensive experiments on popular KITTI and Cityscapes datasets. Benefitting from the proposed parallax-aware transformer, our approach achieves superior performance in both quantitative and qualitative evaluations.