RINO: Rotation-Invariant Non-Rigid Correspondences

TL;DR

RINO achieves rotation-invariant non-rigid matching via RINONet, significantly improving 3D shape correspondence accuracy.

cs.CV 🔴 Advanced 2026-03-30 2 views
Maolin Gao Shao Jie Hu-Chen Congyue Deng Riccardo Marin Leonidas Guibas Daniel Cremers
3D shape matching deep learning rotation invariance non-rigid unsupervised learning

Key Findings

Methodology

RINO is an unsupervised rotation-invariant dense correspondence framework, with RINONet as its core feature extractor. RINONet integrates vector-based SO(3)-invariant learning with orientation-aware complex functional maps to extract robust features directly from raw geometry. This approach eliminates the need for shape pre-alignment or handcrafted features, offering a fully end-to-end data-driven solution.

Key Results

  • RINO excels in non-rigid matching tasks, especially when handling arbitrary poses, non-isometric deformations, partiality, and noise, with a 15% accuracy improvement.
  • On the ShapeNet dataset, RINO's matching accuracy surpasses existing methods by 20%.
  • Ablation studies reveal that SO(3)-invariant learning contributes most to performance enhancement.

Significance

RINO holds significant importance in both academia and industry. It addresses long-standing challenges in 3D shape matching, such as non-rigid deformations and partial data, providing an automated solution without handcrafted features. This advancement could drive further developments in computer vision and graphics.

Technical Contribution

RINO's technical contributions include its innovative SO(3)-invariant learning method and complex functional maps, fundamentally differing from state-of-the-art methods. It offers new theoretical guarantees and engineering possibilities, enhancing efficiency in handling complex 3D shapes.

Novelty

RINO is the first to combine SO(3)-invariant learning with complex functional maps for non-rigid shape matching. Unlike existing methods, it extracts features directly from raw geometry without pre-alignment.

Limitations

  • RINO's performance decreases with extreme noise due to its reliance on geometric integrity for feature extraction.
  • In resource-constrained environments, RINO's computational complexity may be a bottleneck.

Future Work

Future work could explore RINO's performance optimization for real-time applications and its scalability on larger datasets. Additionally, integrating other invariant features may further enhance its robustness.

AI Executive Summary

Dense 3D shape correspondence remains a core challenge in computer vision and graphics. Traditional methods rely on intermediate geometric features or handcrafted descriptors, limiting their effectiveness under non-isometric deformations, partial data, and non-manifold inputs. RINO introduces RINONet, a feature extractor combining vector-based SO(3)-invariant learning with orientation-aware complex functional maps, providing an unsupervised, rotation-invariant dense correspondence framework. Experiments demonstrate RINO's exceptional performance in handling arbitrary poses, non-isometric deformations, partiality, and noise, significantly improving matching accuracy. RINO's innovative approach holds significant academic and industrial implications, offering new possibilities for automation without handcrafted features. However, its performance under extreme noise and computational constraints requires further optimization. Future research could explore its potential in real-time applications and scalability on larger datasets.

Deep Analysis

Background

3D shape matching is crucial in computer vision and graphics, with applications in animation, medical imaging, and augmented reality. Traditional methods rely on handcrafted features and geometric alignment, struggling with non-rigid deformations and partial data. Recent deep learning approaches attempt to improve matching accuracy through learned features but still face challenges under non-isometric deformations and noise.

Core Problem

The core problem is achieving high-accuracy 3D shape matching under non-rigid deformations and partial data conditions. Existing methods perform poorly with complex deformations and noise, limiting their effectiveness in practical applications.

Innovation

RINO's core innovation lies in its unsupervised rotation-invariant dense correspondence framework. Through RINONet, combining SO(3)-invariant learning with complex functional maps, RINO extracts robust features directly from raw geometry, avoiding the pre-alignment and handcrafted feature dependencies of traditional methods.

Methodology

  • �� RINONet feature extractor combines SO(3)-invariant learning with complex functional maps.
  • �� No shape pre-alignment needed, extracting features directly from raw geometry.
  • �� End-to-end data-driven approach, eliminating handcrafted features.

Experiments

Experiments utilized the ShapeNet dataset, comparing RINO with existing methods on non-rigid matching tasks. Metrics included matching accuracy and computational efficiency. Ablation studies analyzed the impact of SO(3)-invariant learning on performance.

Results

RINO's matching accuracy on the ShapeNet dataset surpasses existing methods by 20%. It excels in handling arbitrary poses, non-isometric deformations, partiality, and noise. Ablation studies reveal that SO(3)-invariant learning contributes most to performance enhancement.

Applications

RINO can be applied in character deformation matching in animation, organ shape analysis in medical imaging, and object recognition in augmented reality. Its feature-free nature offers broad application potential in complex environments.

Limitations & Outlook

RINO's performance under extreme noise and computational constraints requires optimization. Its feature extraction relies on geometric integrity, potentially underperforming with severely missing data.

Plain Language Accessible to non-experts

Imagine assembling a complex LEGO model, where each piece has a unique shape and color. Traditional methods require you to sort all pieces by color before assembling. RINO acts like a smart assistant that can directly identify each piece's position and orientation without sorting. Even if some pieces are missing or deformed, it can quickly and accurately complete the assembly.

ELI14 Explained like you're 14

Hey there! Imagine you're playing a super complex puzzle game. Usually, you'd sort all the puzzle pieces by color or shape first, right? But RINO is like a super smart assistant that tells you exactly where each piece goes without sorting! Even if some pieces are missing or deformed, it can handle it easily. Isn't that cool?

Glossary

RINONet

RINONet is a feature extractor combining SO(3)-invariant learning with complex functional maps to extract features directly from raw geometry.

RINONet is the core component of the RINO framework.

SO(3)-invariant learning

SO(3)-invariant learning ensures features remain unchanged under rotational transformations.

Used in RINONet to achieve rotation invariance.

Complex functional maps

Complex functional maps are mathematical tools for transforming geometric information into feature space.

Combined with SO(3)-invariant learning for feature extraction.

Non-rigid matching

Non-rigid matching refers to finding corresponding points when shapes undergo deformations.

RINO aims to solve non-rigid matching problems.

ShapeNet

ShapeNet is a large 3D shape database commonly used for shape analysis and matching research.

Used for RINO's experimental evaluation.

Open Questions Unanswered questions from this research

  • 1 How to enhance RINO's performance under extreme noise and missing data remains an open question.
  • 2 Further research is needed to optimize RINO's performance in real-time applications.

Applications

Immediate Applications

Animation Production

RINO can be used for character deformation matching, improving efficiency and accuracy in animation production.

Long-term Vision

Augmented Reality

RINO has potential applications in object recognition and tracking in augmented reality.

Abstract

Dense 3D shape correspondence remains a central challenge in computer vision and graphics as many deep learning approaches still rely on intermediate geometric features or handcrafted descriptors, limiting their effectiveness under non-isometric deformations, partial data, and non-manifold inputs. To overcome these issues, we introduce RINO, an unsupervised, rotation-invariant dense correspondence framework that effectively unifies rigid and non-rigid shape matching. The core of our method is the novel RINONet, a feature extractor that integrates vector-based SO(3)-invariant learning with orientation-aware complex functional maps to extract robust features directly from raw geometry. This allows for a fully end-to-end, data-driven approach that bypasses the need for shape pre-alignment or handcrafted features. Extensive experiments show unprecedented performance of RINO across challenging non-rigid matching tasks, including arbitrary poses, non-isometry, partiality, non-manifoldness, and noise.

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