3D Sketch-aware Semantic Scene Completion via Semi-supervised Structure Prior

TL;DR

Proposed 3D Sketch-aware Semantic Scene Completion method improves SSC task performance by 7.8% on NYU dataset.

cs.CV 🔴 Advanced 2020-03-31 33 views
Xiaokang Chen Kwan-Yee Lin Chen Qian Gang Zeng Hongsheng Li
3D reconstruction semantic segmentation semi-supervised learning structure prior deep learning

Key Findings

Methodology

The paper introduces a novel geometric embedding strategy using 3D sketch-aware feature embedding to effectively encode geometric information. This method integrates a 3D Sketch Hallucination module and Conditional Variational Autoencoder (CVAE) to achieve efficient semantic scene completion under low-resolution voxel representation. A semi-supervised structure prior learning strategy guides the inference of occupancy and semantic labels.

Key Results

  • On the NYU dataset, the proposed method improves scene completion IoU by 7.8% and semantic scene completion mIoU by 2.6% compared to CCPNet.
  • On the NYUCAD dataset, the method outperforms CCPNet by 1.8% in SC IoU and 2.0% in SSC mIoU.
  • Ablation studies confirm the effectiveness of the 3D Sketch Hallucination Module, boosting SC IoU to 84.2% and SSC mIoU to 55.2%.

Significance

This research breaks the performance bottleneck of low-resolution voxel representation by introducing 3D sketch-aware feature embedding, achieving significant performance improvements in semantic scene completion tasks. Its innovative geometric embedding strategy offers new insights for 3D scene understanding in computer vision, with broad potential in applications like augmented reality, surveillance, and robotics.

Technical Contribution

Technical contributions include a novel geometric embedding strategy, integrating a 3D Sketch Hallucination module and CVAE, significantly enhancing semantic scene completion performance. Additionally, the method achieves efficient 3D reconstruction under low-resolution input, reducing computational costs.

Novelty

This study is the first to apply 3D sketch-aware feature embedding to semantic scene completion tasks, significantly improving performance with a semi-supervised structure prior learning strategy. Compared to existing methods, it maintains high accuracy under low resolution.

Limitations

  • The method may perform poorly in complex scenes, especially with severe geometric information loss.
  • High dependence on 3D sketch generation may affect model robustness.

Future Work

Future research could explore more efficient 3D sketch generation methods or integrate information from other modalities to enhance performance in complex scenes. Additionally, studying how to train on larger datasets is an important direction.

AI Executive Summary

The task of semantic scene completion aims to predict a complete 3D voxel representation and semantic labels of objects in a scene from a single-view observation. However, as voxel resolution increases, computational costs grow exponentially, forcing existing methods to operate at low resolutions, sacrificing detail prediction accuracy.

This paper proposes a novel geometric embedding strategy using 3D sketch-aware feature embedding to effectively encode geometric information. By integrating a 3D Sketch Hallucination module and Conditional Variational Autoencoder (CVAE), efficient semantic scene completion is achieved under low-resolution voxel representation. Experimental results demonstrate that this method significantly outperforms existing methods on the NYU dataset.

The study's innovation lies in its geometric embedding strategy and semi-supervised structure prior learning strategy, offering new insights for 3D scene understanding in computer vision. Future research could explore more efficient 3D sketch generation methods or integrate information from other modalities to enhance performance in complex scenes.

Deep Analysis

Background

Semantic scene completion is a crucial task in computer vision, aiming to understand 3D world geometry and semantics from partial observations. Existing methods often rely on 3D convolutional neural networks for depth feature learning, but these methods struggle with low-resolution voxel representation, leading to performance bottlenecks.

Core Problem

The core problem is achieving efficient semantic scene completion under low-resolution voxel representation. As computational costs grow exponentially with voxel resolution, existing methods must operate at low resolutions, sacrificing detail prediction accuracy.

Innovation

The core innovation of this paper is the novel geometric embedding strategy using 3D sketch-aware feature embedding to effectively encode geometric information. By integrating a 3D Sketch Hallucination module and CVAE, efficient semantic scene completion is achieved under low-resolution voxel representation.

Methodology

  • �� Propose 3D sketch-aware feature embedding to effectively encode geometric information.
  • �� Integrate a 3D Sketch Hallucination module using CVAE to generate diverse 3D sketches.
  • �� Use a semi-supervised structure prior learning strategy to guide occupancy and semantic label inference.

Experiments

Experiments were conducted on NYU, NYUCAD, and SUNCG datasets, using precision, recall, and IoU as evaluation metrics. Ablation studies confirmed the effectiveness of the 3D Sketch Hallucination Module, and comparisons with existing methods were made.

Results

On the NYU dataset, the method improves scene completion IoU by 7.8% and semantic scene completion mIoU by 2.6%. Ablation studies confirm the effectiveness of the 3D Sketch Hallucination Module, significantly boosting performance.

Applications

The method has broad application potential in fields like augmented reality, surveillance, and robotics, enabling efficient 3D reconstruction under low-resolution input.

Limitations & Outlook

The method may perform poorly in complex scenes, especially with severe geometric information loss. High dependence on 3D sketch generation may affect model robustness.

Plain Language Accessible to non-experts

Imagine you're in a maze with only a partial map. You need to infer the entire maze layout based on this map and some known landmarks. This method acts like a smart assistant, quickly generating a complete maze map based on your partial map and landmarks. By using 3D sketch-aware feature embedding, it effectively captures geometric information, maintaining high accuracy even at low resolutions.

ELI14 Explained like you're 14

Imagine you're playing a 3D puzzle game but only have some pieces. You need to guess the whole picture based on these pieces. This method is like a super puzzle assistant, quickly inferring the complete picture based on your pieces. By using 3D sketch-aware feature embedding, it effectively captures geometric information, maintaining high accuracy even at low resolutions.

Glossary

3D Sketch-aware Feature Embedding

A novel geometric embedding strategy to effectively encode geometric information.

Used in semantic scene completion tasks to help infer invisible areas of the scene.

Conditional Variational Autoencoder (CVAE)

A generative model used to generate diverse 3D sketches from partial observations.

Used in the 3D Sketch Hallucination Module to generate diverse 3D sketches.

Semantic Scene Completion

The task of simultaneously predicting 3D voxel representation and semantic labels of objects in a scene.

The core task of this paper, achieved through 3D sketch-aware feature embedding.

Semi-supervised Structure Prior Learning

A learning strategy that combines known structural information to guide model learning.

Used to guide occupancy and semantic label inference.

Voxel Resolution

The level of detail in 3D space voxels, affecting computational costs and detail prediction accuracy.

This paper achieves efficient semantic scene completion under low-resolution input.

Open Questions Unanswered questions from this research

  • 1 How to improve model robustness in complex scenes, especially with severe geometric information loss.
  • 2 How to train on larger datasets to verify the method's generality.

Applications

Immediate Applications

Augmented Reality

Enhance the realism and interactivity of augmented reality applications through efficient 3D reconstruction technology.

Long-term Vision

Intelligent Surveillance

Utilize semantic scene completion technology to achieve smarter surveillance systems capable of identifying and tracking targets at low resolutions.

Abstract

The goal of the Semantic Scene Completion (SSC) task is to simultaneously predict a completed 3D voxel representation of volumetric occupancy and semantic labels of objects in the scene from a single-view observation. Since the computational cost generally increases explosively along with the growth of voxel resolution, most current state-of-the-arts have to tailor their framework into a low-resolution representation with the sacrifice of detail prediction. Thus, voxel resolution becomes one of the crucial difficulties that lead to the performance bottleneck. In this paper, we propose to devise a new geometry-based strategy to embed depth information with low-resolution voxel representation, which could still be able to encode sufficient geometric information, e.g., room layout, object's sizes and shapes, to infer the invisible areas of the scene with well structure-preserving details. To this end, we first propose a novel 3D sketch-aware feature embedding to explicitly encode geometric information effectively and efficiently. With the 3D sketch in hand, we further devise a simple yet effective semantic scene completion framework that incorporates a light-weight 3D Sketch Hallucination module to guide the inference of occupancy and the semantic labels via a semi-supervised structure prior learning strategy. We demonstrate that our proposed geometric embedding works better than the depth feature learning from habitual SSC frameworks. Our final model surpasses state-of-the-arts consistently on three public benchmarks, which only requires 3D volumes of 60 x 36 x 60 resolution for both input and output. The code and the supplementary material will be available at https://charlesCXK.github.io.

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