Optical Flow Estimation Using Event Frames for Nonlinear Motion

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Solution Overview

Problem

Conventional optical flow estimation methods assume linear motion between adjacent image frames, leading to inaccurate estimation of optical flows to any moment between the frames due to actual non-linear motions in scenes.

Innovation Solution

An optical flow estimation method utilizing a pixel camera and an event-based camera to capture pixel and luminance changes, employing a lightweight convolutional neural network for accurate estimation of optical flows by incorporating event frames, which capture both linear and non-linear motions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If linear motion assumption is used to allocate optical flows between adjacent frames, then the calculation is simple, but the accuracy of optical flow estimation is low

Engineering Contradiction:
Improvecalculation simplicityVSAvoidoptical flow estimation accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent introduces event data as an intermediary element between adjacent image frames. Event data captures luminance changes at high temporal resolution and serves as a mediator to guide the allocation of optical flows, enabling accurate representation of non-linear motion without complex calculations

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the parameter used for optical flow allocation from uniform time-based weighting to event-driven dynamic weighting. By using event data to determine weight values, the system adapts to actual motion patterns, improving accuracy while maintaining computational efficiency

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If event-based camera is used to capture luminance changes, then the accuracy of motion information is improved, but the device complexity increases

Engineering Contradiction:
Improvemotion information accuracyVSAvoidsensor system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges data from two different sensor types (pixel camera and event-based sensor) into a unified optical flow estimation framework. By combining image frame data with event data, the system achieves high-accuracy motion capture while leveraging the complementary strengths of both sensors

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent creates a multi-functional system where event data serves multiple purposes: capturing high-speed motion, guiding optical flow allocation, and providing temporal information. This universal use of event data maximizes the value of the additional sensor, justifying the increased device complexity

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

Data Source

PatentEP4407557B1Optical flow estimation method and device
Publication Date: 2026.02.11 HUAWEI TECH CO LTD
  • EP4407557B1 patent drawingFigure 1(a)~1(b)
  • EP4407557B1 patent drawingFigure 2(a)~3
  • EP4407557B1 patent drawingFigure 4

AI summary

This application provides an optical flow estimation method and apparatus, to improve accuracy of estimating optical flows from two adjacent image frames to any moment between the two adjacent image frames. The method may include: obtaining a first image frame and a second image frame, where the first image frame and the second image frame are any two adjacent image frames in an image sequence, and the image sequence is obtained by photographing a target scene; obtaining a first event frame, where the first event frame is used to describe a luminance change of the target scene within a time period from the first image frame to the second image frame; and determining a target optical flow based on the first image frame, the second image frame, and the first event frame, where the target optical flow is an optical flow from the first image frame to a target moment, and the target moment is any moment between the first image frame and the second image frame.