Shared Encoder Neural Network for Scene Flow Estimation

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Solution Overview

Problem

Conventional systems face challenges in estimating scene flow due to limited training data and the use of separate neural networks for optical flow and disparity estimation, which results in sparse ground-truth annotations and non-photorealistic synthetic data.

Innovation Solution

A neural network system is employed that shares a feature encoder to predict both optical flow and disparity, utilizing multi-task learning and self-supervised losses for holistic scene understanding, combining optical flow and disparity estimates to produce scene flow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If separate neural networks are used for optical flow and disparity estimation, then task-specific accuracy may be improved, but device complexity and memory requirements increase

Engineering Contradiction:
Improveoptical flow and disparity estimation accuracyVSAvoidneural network system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines separate neural networks for optical flow and disparity estimation into a unified scene flow estimation network. The shared backbone architecture processes both tasks simultaneously, reducing overall system complexity while maintaining estimation accuracy through integrated feature extraction and task-specific head modules.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The unified neural network is designed to perform multiple functions: it estimates both optical flow and disparity through shared feature extraction layers followed by task-specific prediction heads. This multi-functional design reduces memory requirements and computational overhead compared to maintaining separate specialized networks.

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

2Measurement precision

If synthetic data is used for training, then rich ground-truth annotations are available, but the data lacks photorealism and real-world diversity

Engineering Contradiction:
Improveground-truth annotation qualityVSAvoidreal-world data diversity
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The training approach uses a composite dataset combining synthetic data with rich ground-truth annotations and real photorealistic images. This composite training strategy leverages the advantages of both data types: synthetic data provides precise supervision signals while real images ensure photorealism and diverse scene representations, creating a more robust trained model.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The system performs preliminary training or pre-training on synthetic data with rich annotations to establish baseline performance, then fine-tunes on photorealistic real-world data. This staged approach allows the model to first learn from perfectly annotated synthetic scenarios before adapting to the complexity and variability of real-world scenes.

Inventive Principle:
Principle #10Preliminary action

3Productivity

If limited training data is used, then training speed is improved, but training quality and model performance deteriorate

Engineering Contradiction:
Improvetraining speedVSAvoidmodel estimation accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The system enables continuous training by efficiently processing and utilizing all available training data through the unified neural network architecture. The shared feature extraction and multi-task learning framework allow the model to continuously learn from diverse data samples without requiring excessive computational resources, maintaining both training speed and quality.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The unified scene flow estimation network performs self-supervised learning where the model generates its own training signals through consistency constraints and photometric losses. This self-service capability allows the system to effectively utilize limited labeled data while automatically creating additional supervision from unlabeled photorealistic images, improving training quality without proportionally increasing data requirements.

Inventive Principle:
Principle #25Self-service

Data Source

PatentUS10986325B2Scene flow estimation using shared features
Publication Date: 2021.04.20 NVIDIA CORP
  • US10986325B2 patent drawing
  • US10986325B2 patent drawing
  • US10986325B2 patent drawing

AI summary

Scene flow represents the three-dimensional (3D) structure and movement of objects in a video sequence in three dimensions from frame-to-frame and is used to track objects and estimate speeds for autonomous driving applications. Scene flow is recovered by a neural network system from a video sequence captured from at least two viewpoints (e.g., cameras), such as a left-eye and right-eye of a viewer. An encoder portion of the system extracts features from frames of the video sequence. The features are input to a first decoder to predict optical flow and a second decoder to predict disparity. The optical flow represents pixel movement in (x,y) and the disparity represents pixel movement in z (depth). When combined, the optical flow and disparity represent the scene flow.