Bi-directional Hierarchical Motion Estimation for Frame Rate Conversion

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Solution Overview

Problem

Existing frame rate conversion algorithms for video processing often fail to accurately compensate for motion in video sequences, leading to poor quality interpolation and artifacts, especially when converting between different frame rates like 24fps to 60fps or 25fps to 50fps, and do not effectively handle high-definition television frame rates.

Innovation Solution

The implementation of bi-directional, hierarchical motion estimation and compensation, combined with frame interpolation, which uses motion vectors to refine motion estimation at increasing resolutions and handle fast motion frames by assigning weights to pixel blocks, ensuring reliable motion vectors and minimizing errors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional frame rate conversion algorithms are used, then the conversion process is simple, but the motion compensation accuracy is poor leading to artifacts and low quality interpolation

Engineering Contradiction:
Improvemotion compensation accuracyVSAvoidalgorithm complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the motion estimation process into multiple hierarchical levels (e.g., coarse to fine resolution stages). Each level processes motion vectors at different granularities, allowing accurate motion compensation without requiring a single overly complex algorithm. This multi-level segmentation resolves the contradiction by distributing computational complexity across manageable stages while maintaining high precision.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces temporal dimension by using bi-directional motion estimation (comparing current frame with both previous and next frames) in addition to spatial dimension analysis. This multi-dimensional approach enhances motion compensation accuracy by leveraging information from multiple temporal references, resolving the accuracy-complexity tradeoff through dimensional expansion rather than simple algorithmic complexity increase.

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

2Reliability

If frame rate conversion is performed without motion compensation, then the processing speed is fast, but the output quality is poor with visible artifacts

Engineering Contradiction:
Improveoutput qualityVSAvoidprocessing speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent performs motion estimation and compensation as preliminary actions before actual frame interpolation. By pre-calculating motion vectors and compensating for motion effects in advance, the system ensures high output quality is achieved during the quality-critical phases, while allowing faster processing during the actual frame generation phases. This sequencing resolves the contradiction by prioritizing quality where it matters most.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent maintains continuous motion compensation across multiple frames through temporal coherence in motion vector calculation. Rather than treating each frame conversion independently, the system continuously refines motion estimates using information from adjacent frames, ensuring consistent quality throughout the video sequence while optimizing processing throughput through efficient reuse of intermediate results.

Inventive Principle:
Principle #20Continuity of useful action

3Measurement precision

If high-definition television frame rates are handled with basic conversion algorithms, then the processing load is low, but the quality of fast motion frames deteriorates

Engineering Contradiction:
Improvefast motion estimation accuracyVSAvoidprocessing load
Core Design Contradiction:
Measurement precisionVSUse of energy by stationary object

Solution Approach 1:

The patent implements dynamic motion estimation that adapts its complexity based on detected motion magnitude. For fast motion frames, the system automatically increases estimation precision and uses more reference frames, while for static or slow-motion frames, it reduces processing intensity. This dynamic adaptation resolves the contradiction by allocating processing resources according to actual needs, maintaining high accuracy for fast motion while optimizing overall energy consumption.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes key processing parameters (such as search window size, block size, and number of comparison frames) based on the detected motion characteristics of each frame. When fast motion is detected, parameters are adjusted to enhance estimation accuracy; when motion is minimal, parameters are reduced to lower processing load. This parameter-based adaptation resolves the accuracy-load contradiction by making the system responsive to actual content requirements rather than using fixed high-complexity processing for all frames.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS8724022B2Frame rate conversion using motion estimation and compensation
Publication Date: 2014.05.13 TAHOE RES LTD
  • US8724022B2 patent drawing
  • US8724022B2 patent drawing
  • US8724022B2 patent drawing

AI summary

Frame rate conversion may be implemented using motion estimation results. Specifically, as part of the motion estimation, pixels may be labeled based on the number of matching pixels in subsequent frames. For example, pixels may be labeled as to whether they have no matching pixels, one matching pixels, or multiple matching pixels. The motion estimation and pixel labeling may then be used to interpolate pixels for frame rate conversion.