GANerated Hands for Real-time 3D Hand Tracking from Monocular RGB

We address the highly challenging problem of real-time 3D hand tracking based on a monocular RGB-only sequence. Our tracking method combines a convolutional neural network with a kinematic 3D hand model, such that it generalizes well to unseen data, is robust to occlusions and varying camera viewpoints, and leads to anatomically plausible as well as temporally smooth hand motions. For training our CNN we propose a novel approach for the synthetic generation of training data that is based on a geometrically consistent image-to-image translation network. To be more specific, we use a neural network that translates synthetic images to "real" images, such that the so-generated images follow the same statistical distribution as real-world hand images. For training this translation network we combine an adversarial loss and a cycle-consistency loss with a geometric consistency loss in order to preserve geometric properties (such as hand pose) during translation. We demonstrate that our hand tracking system outperforms the current state-of-the-art on challenging RGB-only footage

Frustum PointNets for 3D Object Detection from RGB-D Data

In this work, we study 3D object detection from RGB-D data in both indoor and outdoor scenes. While previous methods focus on images or 3D voxels, often obscuring natural 3D patterns and invariances of 3D data, we directly operate on raw point clouds by popping up RGB-D scans. However, a key challenge of this approach is how to efficiently localize objects in point clouds of large-scale scenes (region proposal). Instead of solely relying on 3D proposals, our method leverages both mature 2D object detectors and advanced 3D deep learning for object localization, achieving efficiency as well as high recall for even small objects. Benefited from learning directly in raw point clouds, our method is also able to precisely estimate 3D bounding boxes even under strong occlusion or with very sparse points. Evaluated on KITTI and SUN RGB-D 3D detection benchmarks, our method outperforms the state of the art by remarkable margins while having real-time capability.Comment: 15 pages, 12 figures, 14 table

2D+3D Indoor Scene Understanding from a Single Monocular Image

Scene understanding, as a broad field encompassing many subtopics, has gained great interest in recent years. Among these subtopics, indoor scene understanding, having its own specific attributes and challenges compared to outdoor scene under- standing, has drawn a lot of attention. It has potential applications in a wide variety of domains, such as robotic navigation, object grasping for personal robotics, augmented reality, etc. To our knowledge, existing research for indoor scenes typically makes use of depth sensors, such as Kinect, that is however not always available. In this thesis, we focused on addressing the indoor scene understanding tasks in a general case, where only a monocular color image of the scene is available. Specifically, we first studied the problem of estimating a detailed depth map from a monocular image. Then, benefiting from deep-learning-based depth estimation, we tackled the higher-level tasks of 3D box proposal generation, and scene parsing with instance segmentation, semantic labeling and support relationship inference from a monocular image. Our research on indoor scene understanding provides a comprehensive scene interpretation at various perspectives and scales. For monocular image depth estimation, previous approaches are limited in that they only reason about depth locally on a single scale, and do not utilize the important information of geometric scene structures. Here, we developed a novel graphical model, which reasons about detailed depth while leveraging geometric scene structures at multiple scales. For 3D box proposals, to our best knowledge, our approach constitutes the first attempt to reason about class-independent 3D box proposals from a single monocular image. To this end, we developed a novel integrated, differentiable framework that estimates depth, extracts a volumetric scene representation and generates 3D proposals. At the core of this framework lies a novel residual, differentiable truncated signed distance function module, which is able to handle the relatively low accuracy of the predicted depth map. For scene parsing, we tackled its three subtasks of instance segmentation, se- mantic labeling, and the support relationship inference on instances. Existing work typically reasons about these individual subtasks independently. Here, we leverage the fact that they bear strong connections, which can facilitate addressing these sub- tasks if modeled properly. To this end, we developed an integrated graphical model that reasons about the mutual relationships of the above subtasks. In summary, in this thesis, we introduced novel and effective methodologies for each of three indoor scene understanding tasks, i.e., depth estimation, 3D box proposal generation, and scene parsing, and exploited the dependencies on depth estimates of the latter two tasks. Evaluation on several benchmark datasets demonstrated the effectiveness of our algorithms and the benefits of utilizing depth estimates for higher-level tasks