LA-Net: Layout-Aware Dense Network for Monocular Depth Estimation

Depth estimation from monocular images is an ill-posed and inherently ambiguous problem. Recently, deep learning technique has been applied for monocular depth estimation seeking data-driven solutions. However, most existing methods focus on pursuing the minimization of average depth regression error at pixel level and neglect to encode the global layout of scene, resulting in layout-inconsistent depth map. This paper proposes a novel Layout-Aware Convolutional Neural Network (LA-Net) for accurate monocular depth estimation by simultaneously perceiving scene layout and local depth details. Specifically, a Spatial Layout Network (SL-Net) is proposed to learn a layout map representing the depth ordering between local patches. A Layout-Aware Depth Estimation Network (LDE-Net) is proposed to estimate pixel-level depth details using multi-scale layout maps as structural guidance, leading to layout-consistent depth map. A dense network module is used as the base network to learn effective visual details resorting to dense feed-forward connections. Moreover, we formulate an order-sensitive softmax loss to well constrain the ill-posed depth inferring problem. Extensive experiments on both indoor scene (NYUD-v2) and outdoor scene (Make3D) datasets have demonstrated that the proposed LA-Net outperforms the state-of-the-art methods and leads to faithful 3D projections.