The prohibitive cost of annotations for fully supervised 3D indoor object detection limits its practicality. In this work, we propose Random Prompt Assisted Weakly-supervised 3D Object Detection, termed as Prompt3D, a weakly-supervised approach that leverages position-level labels to overcome this challenge. Explicitly, our method focuses on enhancing labeling using synthetic scenes crafted from 3D shapes generated via random prompts. First, a Synthetic Scene Generation (SSG) module is introduced to assemble synthetic scenes with a curated collection of 3D shapes, created via random prompts for each category. These scenes are enriched with automatically generated point-level annotations, providing a robust supervisory frame-work for training the detection algorithm. To enhance the transfer of knowledge from virtual to real datasets, we then introduce a Prototypical Proposal Feature Alignment (PPFA) module. This module effectively alleviates the domain gap by directly minimizing the distance between feature prototypes of the same class proposals across two domains. Compared with sota BR, our method improves by 5.4% and 8.7% on mAP with VoteNet and GroupFree3D serving as detectors respectively, demonstrating the effectiveness of our proposed method. Code is available at: https://github.com/huishengye/prompt3d.

This paper proposes a practical two-stage method to enhance the depth channel of low-quality RGB-D videos. At the first stage of the proposed method, we select several key frames from an input RGB-D video and recover them with a new MRF-regularized low-rank matrix completion method. At the second stage, we introduce a novel Laplacian smoothing algorithm to smoothly expand the recovered key depth frames to other in-between frames. With associated weights extracted from color images and a depth confidence constraint, we are able to recover each in-between frame faithfully and guarantee long-range temporal consistency. Experiments show that our method can generate high-quality and spatiotemporally coherent RGB-D videos for a wide range of scene configurations and achieve the state-of-the-art performance. Several applications further validate the effectiveness of the proposed method.