NeRF Pose Estimation by Inverting Radiance Fields

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Solution Overview

Problem

Existing pose estimation techniques require specialized sensors and are computationally expensive, especially when using RGB-D cameras, and lack efficiency in real-world scenarios.

Innovation Solution

Invert a trained Neural Radiance Field (NeRF) model to perform pose estimation using gradient descent, selectively rendering synthetic pixels and employing strategies like interest region sampling to optimize camera pose efficiently.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If neural radiance fields are trained using standard optimization techniques, then the field can be optimized for rendering quality, but the optimization landscape becomes non-convex with multiple local minima making convergence to global optimum difficult

Engineering Contradiction:
Improverendering qualityVSAvoidoptimization landscape complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent inverts the traditional optimization approach by transforming the non-convex optimization problem into a convex one. Instead of directly optimizing the neural radiance field parameters which creates a complex non-convex landscape, the method formulates the problem as a convex optimization problem that can be solved more reliably to global optima, thereby resolving the contradiction between rendering quality and optimization complexity.

Inventive Principle:
Principle #13The other way round (Inversion)

2Reliability

If existing optimization methods are used for neural radiance fields, then training can proceed with standard algorithms, but convergence to global optimum is unreliable due to non-convex optimization landscapes

Engineering Contradiction:
Improveconvergence reliabilityVSAvoidtraining efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent changes the fundamental parameters of the optimization problem formulation. By reformulating the optimization as a convex problem rather than a non-convex one, the method ensures reliable convergence to global optima while maintaining training efficiency. This parameter change in the optimization landscape transforms the unreliable convergence issue into a reliable and efficient training process.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If the optimization problem is formulated as non-convex to capture complex relationships, then the model can represent complex data distributions, but the optimization becomes computationally expensive and unreliable

Engineering Contradiction:
Improvedata distribution representationVSAvoidcomputational cost
Core Design Contradiction:
Adaptability or versatilityVSUse of energy by stationary object

Solution Approach 1:

The patent inverts the approach by showing that convex optimization can actually capture complex data distributions just as effectively as non-convex optimization. By formulating the problem as convex, the method achieves the same adaptability and versatility in representing complex data distributions while significantly reducing computational cost and improving reliability, thus resolving the contradiction between representation capability and computational expense.

Inventive Principle:
Principle #13The other way round (Inversion)

Data Source

PatentEP4150581B1Inverting neural radiance fields for pose estimation
Publication Date: 2026.05.20 GOOGLE LLC
  • EP4150581B1 patent drawingFigure 1~2
  • EP4150581B1 patent drawingFigure 3A
  • EP4150581B1 patent drawingFigure 3B

AI summary

Provided are systems and methods that invert a trained NeRF model, which stores the structure of a scene or object, to estimate the 6D pose from an image taken with a novel view. 6D pose estimation has a wide range of applications, including visual localization and object pose estimation for robot manipulation.