Temporal Motion Vector Filtering for Video Artifacts
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Solution Overview
Problem
Existing video processing technologies face challenges in determining motion vectors efficiently and accurately, leading to discrepancies between expected and displayed image motion, particularly at low display refresh rates, which can result in artifacts like area flicker and motion judder.
Innovation Solution
A recursive hierarchical approach using temporal vector partitioning to determine motion vectors, where vectors are clustered and representative vectors are selected based on minimum sum of absolute differences, allowing for efficient and accurate motion compensation across multiple resolution levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If motion vectors are computed at pixel level, then motion accuracy is improved, but computational complexity increases significantly
Solution Approach 1:
The patent applies segmentation by dividing the image into patches and computing motion vectors at patch level rather than pixel level. This reduces computational complexity while maintaining acceptable motion accuracy through the use of multiple patches per block and hierarchical refinement processes.
Solution Approach 2:
The patent introduces a hierarchical dimension by computing motion vectors at multiple resolution levels (e.g., 1/4, 1/2, and full resolution). This allows the system to achieve high accuracy at fine resolutions while using coarser resolutions for initial estimates, thereby reducing overall computational burden.
2Object-affected harmful factors
If display refresh rate is increased by repeating fields, then area flicker is reduced, but motion judder artifacts are introduced
Solution Approach 1:
The patent applies preliminary action by computing motion-compensated interpolated frames in advance between original fields. This allows the display system to show smooth intermediate frames that match expected motion trajectories, preventing both area flicker and motion judder from occurring during playback.
Solution Approach 2:
The patent changes the temporal parameter by generating interpolated frames at intermediate time points between original fields. This creates a higher effective refresh rate with smooth motion progression, eliminating the need to simply repeat fields and thereby avoiding both flicker and judder artifacts.
3Measurement precision
If multiple representative vectors are tested for each cluster, then motion vector accuracy is improved, but computational requirements increase
Solution Approach 1:
The patent applies partial action by testing a limited number of representative vectors (e.g., 2-5) per cluster rather than exhaustively testing all possible vectors. This provides sufficient motion accuracy for most cases while maintaining computational efficiency, with the option to refine selected vectors through hierarchical refinement if needed.
Data Source
AI summary
Methods and apparatus, including computer program products, implementing and using techniques for performing temporal motion vector filtering in digital video are disclosed. A recursive hierarchical process is used to determine a motion vector. In the recursive hierarchical process, a neighborhood of old motion vectors is filtered to generate a first estimated motion vector for an image patch in a pair of two image frames. The filtering process uses multiple vectors in a neighborhood around the old motion vector to improve the prediction of the first estimated motion vector. The temporal vector partitioning process separates motion vectors associated with an object from motion vectors associated with a background before selecting a best motion vector, which improves the selection process. The process also works well in the absence of object/background boundaries, as in this case the outlier (incorrect) vector or vectors will be separated out from the good vectors.