Affine Motion Estimation Using Epipolar Constraint

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Solution Overview

Problem

Complex motion models for video encoding in vehicles result in high processing, memory, and time requirements, leading to increased bitrate and degraded prediction quality due to challenges in determining optimal parameters.

Innovation Solution

Implementing epipolar-based constraints to reduce the complexity of affine motion estimation by determining an epipolar curve from block corners, using known camera geometry and minimizing block matching errors to constrain the search to a single parameter.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If complex motion models are used for video encoding, then prediction quality is improved, but processing complexity and memory requirements increase

Engineering Contradiction:
Improveprediction qualityVSAvoidprocessing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent changes the parameter space by constraining the affine motion model search from multiple parameters to a single parameter along the epipolar curve. This reduces the complexity of determining optimal motion parameters while maintaining prediction accuracy for vehicles with known geometry

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces the epipolar curve as an intermediary constraint that connects the current block to the reference picture. This curve, derived from known vehicle camera geometry, serves as a mediator that simplifies the motion search process while preserving prediction quality

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If complex motion models are used for video encoding, then prediction quality is improved, but encoding time increases

Engineering Contradiction:
Improveprediction qualityVSAvoidencoding time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent reduces the number of parameters to be optimized from multiple affine parameters to a single parameter representing displacement along the epipolar curve. This parameter reduction significantly decreases encoding time while maintaining prediction quality through the geometric constraint

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If complex motion models are used for video encoding, then prediction quality is improved, but memory requirements increase

Engineering Contradiction:
Improveprediction qualityVSAvoidmemory requirements
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent reduces memory requirements by changing from storing and searching multiple affine parameters to storing and searching a single parameter along the epipolar curve. The known camera geometry is stored once and reused, reducing overall memory usage

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS20250294183A1Affine motion estimation using an epipolar-based constraint
Publication Date: 2025.09.18 QUALCOMM INC
  • US20250294183A1 patent drawing
  • US20250294183A1 patent drawing
  • US20250294183A1 patent drawing

AI summary

An apparatus configured to encode video data is configured to receive a first picture captured at a first time and a first location, receive a second picture captured at a second time and a second location, wherein the second time is different from the first time, and wherein the second location is different than the first location, and encode a current block of the second picture, relative to the first picture, using affine motion prediction with a single parameter search, wherein the single parameter search is performed along an epipolar curve, and wherein the single parameter search is used to determine parameters of an affine motion model.