3D Object Rotation Matrix Estimation Without Gram-Schmidt

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Solution Overview

Problem

Existing neural network models struggle with poor performance in rotation estimation due to the need for Gram-Schmidt orthogonalization (GS processing) to convert a 3×2 matrix into a 3×3 rotation matrix, leading to issues like gradient backflow and numerical gradient errors, resulting in inaccurate object model rotation.

Innovation Solution

The method involves obtaining a first matrix from the target object's information, which is then unbiased Gram-Schmidt orthogonalized to obtain a second rotation matrix, allowing direct rotation of the object model without GS processing, thereby improving model performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If Gram-Schmidt orthogonalization processing is performed on a 3×2 matrix to obtain a 3×3 rotation matrix, then a rotation matrix can be obtained for object model rotation, but the model training process becomes difficult and performance deteriorates due to gradient backflow and numerical gradient errors

Engineering Contradiction:
Improverotation estimation accuracyVSAvoidtraining process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts and removes the Gram-Schmidt orthogonalization processing step from the training pipeline. Instead of requiring the neural network to output a 3×2 matrix that undergoes GS processing, the model directly outputs a 3×3 rotation matrix, eliminating the source of gradient backflow and numerical errors that plagued the training process.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the output parameter structure from a 3×2 matrix to a 3×3 rotation matrix. This parameter change allows the model to directly generate valid rotation matrices without requiring subsequent orthogonalization processing, thereby improving both training stability and rotation estimation accuracy.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If Gram-Schmidt orthogonalization processing is used to convert a 3×2 matrix to a 3×3 rotation matrix, then rotation estimation can be completed, but numerical gradient errors occur during training

Engineering Contradiction:
Improverotation estimation precisionVSAvoidtraining stability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent removes the Gram-Schmidt orthogonalization processing step that caused numerical gradient errors. By having the neural network directly output a 3×3 rotation matrix, the problematic conversion step is eliminated, ensuring training stability while maintaining rotation estimation precision.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of generating a 3×2 matrix and then converting it to a 3×3 rotation matrix through GS processing, the patent inverts the approach by having the model directly generate the final 3×3 rotation matrix. This inversion eliminates the intermediate conversion step that introduced numerical errors.

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

3Productivity

If a 3×2 matrix is output by the neural network model, then the model structure is simpler, but GS processing is required which is not conducive to model training

Engineering Contradiction:
Improvetraining efficiencyVSAvoidoutput matrix structure
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent changes the output parameter structure from a 3×2 matrix to a 3×3 rotation matrix. Although this increases the output dimension, it eliminates the need for subsequent Gram-Schmidt processing, thereby improving training efficiency and overall productivity.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4697258A1Object model rotation method and related device thereof
Publication Date: 2026.02.18 HUAWEI TECH CO LTD
  • EP4697258A1 patent drawingFigure 1
  • EP4697258A1 patent drawingFigure 2a
  • EP4697258A1 patent drawingFigure 2b

AI summary

This application discloses an object model rotation method and a related device thereof. A target model provided in the method can accurately complete rotation estimation, to accurately complete rotation of an object model. The method in this application includes: After information about a target object in a first state is obtained, the information may be input into the target model. Next, the information may be processed by using the target model, to obtain a first matrix, where the first matrix is an n-order matrix, and n is a positive integer greater than or equal to 2. Then, the first matrix may be orthogonalized to obtain a second matrix, where the second matrix is an n-order rotation matrix. Finally, a preset n-dimensional model of the target object may be rotated directly based on the second matrix, to obtain a rotated n-dimensional model of the target object. The preset n-dimensional model of the target object indicates the target object in a second state, and the rotated n-dimensional model of the target object indicates the target object in the first state.