Unsupervised 3D Scene Reconstruction from 2D Images

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Solution Overview

Problem

Current systems for 3D scene reconstruction from 2D images are limited in their ability to generalize to out-of-distribution images, lack manipulability, and require extensive manual annotations or supervised learning, making them unsuitable for real-world applications like augmented reality (AR) and virtual reality (VR) messaging, which need to handle diverse and unseen environments and object compositions.

Innovation Solution

A novel unsupervised object-centric 3D scene understanding framework that uses a causal generative model to reconstruct 3D scenes from 2D images, explicitly representing object shapes, colors, and positions, allowing inference of novel views and manipulations without labeled supervision, even from images outside the training distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If supervised learning with manual annotations is used for 3D scene reconstruction, then manufacturing precision of 3D models is improved, but device complexity and time consumption increase significantly

Engineering Contradiction:
Improve3D reconstruction accuracyVSAvoidannotation time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The system performs self-supervised learning by automatically generating supervision signals from the input images themselves through view synthesis and consistency checks, eliminating the need for manual annotations. The model learns to reconstruct 3D scenes by comparing synthesized views against actual input images, creating its own training data without human intervention.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

A neural radiance field (NeRF) is introduced as an intermediary representation that bridges 2D images and 3D scene understanding. The NeRF serves as a continuous volumetric representation that can be queried from any viewpoint, enabling the system to learn 3D geometry and appearance relationships without requiring explicit 3D annotations.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If traditional 3D reconstruction methods are used, then manufacturing precision is maintained, but adaptability to out-of-distribution images deteriorates

Engineering Contradiction:
Improvereconstruction accuracyVSAvoidgeneralization to unseen environments
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The system employs a dynamic, iterative optimization process that adapts the neural radiance field to each new input image or image set. Rather than using fixed reconstruction algorithms, the model dynamically adjusts its internal representation through gradient-based optimization, allowing it to handle diverse and unseen environments while maintaining reconstruction accuracy.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The approach changes the fundamental parameters of scene representation from discrete mesh vertices to continuous volumetric fields with learnable parameters. By representing scenes as differentiable neural fields with adjustable weights and biases, the system can generalize to out-of-distribution images while maintaining precise 3D reconstruction through parameter optimization.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If object-centric representation is implemented, then manipulability of 3D scenes is improved, but device complexity increases

Engineering Contradiction:
Improvescene manipulabilityVSAvoidmodel complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The system segments the 3D scene into distinct object instances, each represented by its own neural radiance field. This object-centric segmentation allows individual objects to be manipulated, edited, or reasoned about independently while maintaining the overall scene coherence. Each object can be selectively modified without affecting other objects in the scene.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A single neural radiance field framework serves multiple functions: it represents geometry, appearance, and material properties simultaneously, and enables both reconstruction and manipulation tasks. This universal representation approach reduces overall system complexity compared to using separate specialized models for each function.

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

Data Source

PatentUS20240046516A1Estimating 3D scene representations of images
Publication Date: 2024.02.08 SNAP INC
  • US20240046516A1 patent drawing
  • US20240046516A1 patent drawing
  • US20240046516A1 patent drawing

AI summary

Methods and systems are disclosed for performing operations for estimating a 3D scene representation from one or multiple 2D images. The operations include: receiving one or multiple two-dimensional (2D) images representing a real-world environment; and generating, by a machine learning model, a three-dimensional (3D) scene representation of the 2D image, which explicitly (separately) defines the a 3D shape and appearance of the background as well as a 3D position, 3D shape and appearance of each object of the scene depicted in the set of images, where the machine learning model has been trained in an unsupervised approach from a dataset of images and their camera poses (e.g. without any manually labelled annotations, such as depth maps, segmentation masks, object poses).