3D Depth-Aware Keypoints for Self-Supervised Monocular Odometry

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Solution Overview

Problem

Conventional autonomous systems rely on hand-engineered keypoint features for monocular visual odometry, which have limited performance in detecting illumination and viewpoint invariant keypoints, especially in real illumination and non-planar 3D scenes, and require expensive ground-truth labels for supervised learning.

Innovation Solution

A self-supervised learning method that uses a differentiable pose estimation module to jointly optimize keypoints and depths in a structure-from-motion setting, incorporating a 3D multi-view adaptation technique to learn depth-aware keypoints from unlabeled videos without supervision, enabling robust and accurate keypoint detection and matching.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If hand-engineered keypoint features are used for monocular visual odometry, then the system can operate without ground-truth labels, but the performance in detecting illumination and viewpoint invariant keypoints is limited

Engineering Contradiction:
Improvekeypoint detection accuracyVSAvoidsupervised learning requirement
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system uses self-supervised learning where the network learns depth-aware keypoints automatically from monocular video sequences without requiring ground-truth labels. The pose estimation module provides self-supervision by estimating ego-motion and using it to supervise the keypoint detection and depth estimation networks, enabling the system to improve its own performance through unsupervised learning from raw video data

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent introduces depth as an additional dimension to traditional 2D keypoint detection. By learning depth-aware keypoints that incorporate 3D spatial information, the system transforms the problem from 2D image space to 3D space, enabling better invariance to illumination and viewpoint changes through depth information

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Measurement precision

If supervised learning with ground-truth labels is used to improve keypoint detection performance, then detection accuracy improves, but the cost of acquiring and processing ground-truth labels increases

Engineering Contradiction:
Improvekeypoint detection precisionVSAvoidtraining data acquisition cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The system generates its own training signals through self-supervision. The pose estimation module estimates ego-motion between frames, and this estimated motion serves as the supervision signal for training the keypoint detection and depth estimation networks, eliminating the need for expensive ground-truth annotations while maintaining high detection precision

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent introduces an intermediary pose estimation module that bridges the gap between unlabelled video data and supervised learning. This module estimates camera motion and uses it to create pseudo-supervision signals, acting as a mediator that enables high-precision training without direct ground-truth labels

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If conventional 2D keypoint features are used, then the system is computationally efficient, but the performance in non-planar 3D scenes deteriorates

Engineering Contradiction:
Improvecomputational efficiencyVSAvoidperformance in 3D scenes
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The system lifts 2D keypoints into 3D space by incorporating depth information from the depth estimation network. This transformation from 2D to 3D keypoint representation enables the system to handle non-planar 3D scenes effectively while maintaining computational efficiency through the shared backbone network architecture

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

4Reliability

If depth-aware keypoints are learned from unlabeled videos using self-supervised learning, then performance comparable to stereo methods is achieved with minimal drift, but the system complexity increases

Engineering Contradiction:
Improveego-motion estimation accuracyVSAvoidnetwork architecture complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges multiple functions into a unified self-supervised framework. The keypoint detection network and depth estimation network share a common backbone and are jointly trained using self-supervision from pose estimation, combining what would traditionally be separate systems into one integrated architecture that achieves high reliability without proportional increases in complexity

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentUS12073580B2Self-supervised 3D keypoint learning for monocular visual odometry
Publication Date: 2024.08.27 TOYOTA JIDOSHA KK
  • US12073580B2 patent drawing
  • US12073580B2 patent drawing
  • US12073580B2 patent drawing

AI summary

A method for learning depth-aware keypoints and associated descriptors from monocular video for monocular visual odometry is described. The method includes training a keypoint network and a depth network to learn depth-aware keypoints and the associated descriptors. The training is based on a target image and a context image from successive images of the monocular video. The method also includes lifting 2D keypoints from the target image to learn 3D keypoints based on a learned depth map from the depth network. The method further includes estimating a trajectory of an ego-vehicle based on the learned 3D keypoints.