Video Synchronization via Epipolar Constraint Verification

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Solution Overview

Problem

Existing video synchronization methods face challenges in achieving high accuracy due to errors in determining similarity between feature points, particularly when there are multiple visually similar points in a frame, leading to incorrect synchronization of videos captured at different times.

Innovation Solution

A video synchronization apparatus and method that utilizes a synchronization processor to extract feature points, correct matching information using the epipolar constraint, and calculate the fundamental matrix to accurately determine synchronization frames, while removing mismatched points to enhance synchronization accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If conventional feature point matching methods are used to synchronize videos, then the synchronization process is simple, but the synchronization accuracy deteriorates due to erroneous matching when multiple visually similar feature points exist

Engineering Contradiction:
Improvesimplicity of synchronization processVSAvoidsynchronization accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent introduces an epipolar constraint as an intermediary verification mechanism between feature point extraction and matching. The constraint acts as a mediator that filters out erroneous matches while preserving valid correspondences, thereby resolving the contradiction between simple matching processes and accurate synchronization results

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent implements a feedback mechanism where the epipolar constraint evaluation results are used to correct and refine feature point matching. The system continuously verifies matches against the geometric constraint and adjusts matching decisions based on this feedback, improving accuracy without significantly increasing operational complexity

Inventive Principle:
Principle #23Feedback

2Productivity

If feature point similarity is determined by squared error or absolute error in luminance gradient or colors, then the matching process is computationally efficient, but the determination becomes erroneous when multiple visually similar feature points exist in one frame

Engineering Contradiction:
Improvecomputational efficiencyVSAvoidmatching reliability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The epipolar constraint serves as an intermediary that bridges computational efficiency and matching reliability. It provides a geometric verification layer that is computationally tractable yet powerful enough to eliminate erroneous matches among visually similar feature points, thus maintaining both efficiency and reliability

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent transitions from purely photometric comparison (luminance, color) to incorporating geometric dimension (epipolar constraint) in the matching process. This dimensional addition allows the system to distinguish between visually similar but geometrically inconsistent feature points, improving reliability without sacrificing computational efficiency

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

Data Source

PatentEP3316589B1Video synchronization device and video synchronization method
Publication Date: 2024.02.28 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
  • EP3316589B1 patent drawingFigure 1
  • EP3316589B1 patent drawingFigure 2
  • EP3316589B1 patent drawingFigure 3

AI summary

Video synchronization apparatus (200) is a video synchronization apparatus including a processor and a storage connected to the processor. The processor performs a detection step (S12) of detecting a first feature point in a first image frame in a first video, and a second feature point in each of a plurality of second image frames in a second video, an extraction step (S14) of extracting matching points that are a set of the first feature point and a second feature point that is similar to the first feature point, and a synchronization step (S15 or S16) of determining a second image frame to be synchronized with the first image frame, based on a first degree of satisfaction, by a matching point in each second image frame, of a first geometric relationship between the each second image frame and the first image frame.