Adaptive Spatio-Temporal Y/C Separation for Video Artifact Reduction
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Solution Overview
Problem
Conventional Y/C separation techniques in digital video signal processing for NTSC/PAL systems face challenges with inaccurate edge detection, leading to artifacts like cross-luma and cross-color due to discrete selection of filtering methods based on inter-frame/intra-frame correlation, and limitations in two-dimensional spatial separation.
Innovation Solution
A digital video signal processing apparatus that adaptively performs frame-based Y/C separation using spatio-temporal filters with 2D and 3D weight coefficients, applying local vertical comb filtering, horizontal band pass filtering, frame comb filtering, and 2D/3D band pass filtering based on temporal and spatial characteristics of the input video signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If discrete filtering methods (comb filtering or 1D bandpass filtering) are selected based on edge detection, then Y/C separation can be performed with simpler processing, but inaccurate edge detection leads to artifacts like cross-luma and cross-color
Solution Approach 1:
The patent applies dynamics by transitioning from discrete, static filtering method selection to continuous adaptive filtering. The filtering method is dynamically adjusted based on local spatio-temporal characteristics of the video signal, allowing the system to adapt continuously to changing edge directions and correlations rather than being constrained to fixed filtering approaches
Solution Approach 2:
The patent changes the parameters of the filtering operation by using 2D and 3D weight coefficients that adapt to local characteristics. Instead of selecting between fixed filtering methods, the system modifies the filtering parameters (weights, dimensions) continuously based on measured spatio-temporal correlations, enabling accurate Y/C separation across varying edge conditions
2Manufacturing precision
If spatio-temporal filtering is used to improve spatial filtering performance, then picture quality improves, but memory requirements increase due to storing previous and next field/frame data
Solution Approach 1:
The patent applies local quality by performing spatio-temporal filtering with 2D and 3D weight coefficients that are adapted to local spatio-temporal characteristics. Instead of uniformly applying spatio-temporal filtering to the entire frame, the system selectively applies different filtering dimensions (2D spatial, 3D spatio-temporal) based on local correlation patterns, reducing unnecessary memory access while maintaining picture quality
3Manufacturing precision
If conventional spatio-temporal filtering is used, then artifacts are reduced in uniform edge scenarios, but the method fails when edge directions are not uniform due to discrete filter selection
Solution Approach 1:
The patent resolves the adaptability issue by making the filtering approach dynamic and continuous. Instead of discretely selecting filters based on edge direction classification, the system continuously adapts the filtering operation using 2D and 3D weight coefficients that respond to local spatio-temporal characteristics, enabling effective artifact reduction across varying edge directions without requiring accurate edge classification
Solution Approach 2:
The patent applies universality by creating a multi-functional filtering system that can operate in multiple modes (2D spatial filtering, 3D spatio-temporal filtering) depending on the local characteristics. The same filtering framework adapts its behavior to handle different edge scenarios uniformly, eliminating the need for separate discrete filtering methods for different edge conditions
Data Source
AI summary
A digital video signal processing apparatus and method for frame-based adaptive spatio-temporal Y/C separation. In the digital video signal processing apparatus, an adaptive three-dimensional bandpass filter (3D BPF) performs Y/C separation using local comb filtering/1D band pass filtering/frame comb filtering when the edge direction is fixed vertically/horizontally/temporally according to spatio-temporal local characteristics of an image using spatio-temporal filters. When the edge direction is not fixed horizontally/vertically/temporally, the 3D BPF performs 2D or 3D band pass filtering in all directions. Thus, the 3D BPF continuously carries out comb filtering, 1D band pass filtering, frame comb filtering and 2D/3D band pass filtering according to the spatio-temporal local characteristic of the image.