Multi-Object 3D Shape Completion with Latent OctMAE

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Solution Overview

Problem

Existing methods for machine vision struggle to achieve high-quality 3D reconstruction of multiple objects in cluttered scenes from a single RGB-D image, particularly due to the computational and memory constraints of dense voxel grids and the reliance on category-specific shape priors, which hinder real-time deployment on autonomous agents.

Innovation Solution

A hybrid architecture of Octree U-Net and latent 3D masked autoencoders (OctMAE) is employed, incorporating occlusion masking and 3D positional embeddings to efficiently reconstruct 3D shapes, leveraging sparse 3D MAE in the latent space for global understanding and improved performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If dense voxel grids are used for 3D reconstruction, then reconstruction quality is improved, but computational and memory constraints worsen

Engineering Contradiction:
Improvereconstruction qualityVSAvoidcomputational and memory constraints
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent segments the 3D space into hierarchical octree structures, dividing the reconstruction problem into manageable levels of detail. This allows high-quality reconstruction only in regions of interest while using coarser representations elsewhere, reducing overall computational and memory requirements compared to uniform dense voxel grids.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies different levels of reconstruction quality to different spatial regions. High-quality dense voxel representations are used only where necessary (e.g., foreground objects), while background or less important regions use coarser octree representations, optimizing the trade-off between reconstruction quality and computational resources.

Inventive Principle:
Principle #3Local quality

2Manufacturing precision

If category-specific shape priors are used, then reconstruction accuracy is improved, but adaptability to diverse scenes worsens

Engineering Contradiction:
Improvereconstruction accuracyVSAvoidgeneralization across diverse scenes
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The patent employs a universal scene representation framework using octree structures that can handle diverse object categories and scene types without requiring category-specific models. The masked autoencoder learns generalizable features from training data that apply across multiple categories, enabling the system to adapt to novel scenes and object types while maintaining reconstruction accuracy.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent uses learnable parameters in the masked autoencoder that are trained on diverse data to capture general shape priors. These parameters can adapt to different scene configurations and object categories through the training process, providing flexibility and generalization capability while maintaining reconstruction quality across diverse scenes.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If complex reconstruction algorithms are used, then shape completion quality is improved, but processing speed worsens

Engineering Contradiction:
Improveshape completion qualityVSAvoidprocessing speed
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent performs preliminary encoding of the input image into an octree representation and uses a masked autoencoder to predict missing regions during training. This pre-processing and latent space encoding reduce the computational complexity of the final reconstruction step, enabling faster processing while maintaining high shape completion quality through the learned representations.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces a masked autoencoder as an intermediary that operates in a compressed latent space. This intermediary learns to predict occluded or missing regions by attending to visible parts of objects, enabling complex shape completion to be performed efficiently in the latent space before decoding to the final 3D representation, thus improving processing speed without sacrificing quality.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentUS20250296238A1Multi-object 3D shape completion in the wild from a single RGB-d image via latent 3D octmae
Publication Date: 2025.09.25 TOYOTA RESEARCH INSTITUTE INC
  • US20250296238A1 patent drawing
  • US20250296238A1 patent drawing
  • US20250296238A1 patent drawing

AI summary

A method for 3D object shape completion is described. The method includes unprojecting an encoded image feature to obtain an octree feature F. The method also includes generating, by a latent 3D masked autoencoder (MAE) encoder using an input encoded octree feature F, an output latent octree feature FL. The method further includes computing, by a latent 3D MAE decoder using the output latent octree FL and octree mask tokens T, a latent mixed octree feature FML. The method also includes predicting, by an octree decoder from the latent mixed octree feature FML, a completed 3D shape.