Luma Chroma Alignment Interpolation Filters
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Solution Overview
Problem
The misalignment of luma and chroma sample locations in video streams affects the precision of 3D LUT interpolation, leading to inaccuracies in 3D LUT estimation and color gamut conversion.
Innovation Solution
Aligning luma and chroma component sampling locations using interpolation filters, such as those described in Equations (17)-(22), to ensure accurate conversion between BT.709 and BT.2020 color spaces by adjusting luma and chroma components to match sampling locations, allowing for precise 3D LUT interpolation and color gamut scalability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If luma and chroma sample locations are not aligned, then video stream processing is simpler, but 3D LUT interpolation precision deteriorates
Solution Approach 1:
The patent applies preliminary action by performing luma-chroma alignment through interpolation before the 3D LUT estimation process. The alignment unit interpolates luma samples to match chroma sample locations, ensuring that the sampling locations are aligned prior to interpolation. This preliminary alignment step guarantees precise 3D LUT interpolation while maintaining manageable processing complexity through standardized interpolation filters.
2Manufacturing precision
If chroma samples are shifted to align with luma samples, then color gamut conversion accuracy improves, but processing time increases
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the interpolation filter parameters based on the chroma sampling format. Different interpolation filters are selected based on the specific chroma format (e.g., 4:2:0, 4:2:2, 4:4:4), optimizing the balance between alignment accuracy and processing efficiency. This allows precise color gamut conversion while minimizing processing time through parameter-optimized interpolation.
3Reliability
If interpolation filters are used to align sampling locations, then visual artifacts are reduced, but computational complexity increases
Solution Approach 1:
The patent applies local quality by using different interpolation filters tailored to specific chroma sampling formats and locations. The alignment unit selects appropriate interpolation filters (e.g., horizontal, vertical, or bidirectional interpolation) based on the local chroma sampling pattern. This ensures high visual quality by matching the interpolation method to the local sampling structure while keeping computational complexity manageable through selective filter application.
Data Source
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AI summary
Video coding device and method for receiving a picture associated with a first color space, wherein the picture comprises a first component at a first sampling location (CO), a second component at a second sampling location (LO) and the second component at a third sampling location (L4). A first interpolation filter is applied to the second component at the second sampling location (LO) and the second component at the third sampling location (L4) to determine the second component at the first sampling location (L(C0)). The second component at the first sampling location (L(C0)) may be associated with the first color space. A color conversion model is applied to the first component at the first sampling location (CO) and to the second component at the first sampling location (L(C0) ) to translate the first component at the first sampling location to a second color space.