Interlaced Video Pre-Processor Motion Adaptive Filtering
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Solution Overview
Problem
Interlaced video signals often introduce artifacts due to non-compliance with the Nyquist theorem during acquisition, leading to issues like inter-line flicker and combing effects, especially when de-interlacing is inadequate or absent in modern displays that require progressive scan.
Innovation Solution
A pre-processing method that detects vertical motion in progressive scan signals, applies motion-adaptive low-pass filtering in the vertical domain, and then interlaces the signal to generate an interlaced signal with minimal artifacts, ensuring compliance with the Nyquist theorem by filtering out high-frequency components exceeding half the scanning frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If interlaced video signaling is used to reduce bandwidth requirements, then bandwidth efficiency is improved, but artifacts such as inter-line flicker and combing effects are introduced
Solution Approach 1:
The patent applies preliminary low-pass filtering to the progressive scan signal before interlacing to remove high-frequency vertical components that would cause artifacts. This pre-processing action prevents the formation of harmful artifacts while maintaining the bandwidth efficiency of interlaced signaling.
Solution Approach 2:
The patent applies preliminary anti-action by filtering out high-frequency components before interlacing to counteract the potential formation of artifacts. This preventive measure eliminates the root cause of inter-line flicker and combing effects while preserving the bandwidth benefits of interlaced video.
2Object-generated harmful factors
If low-pass filtering is applied to progressive scan signal before interlacing, then artifact reduction is improved, but some blurring and information loss occur
Solution Approach 1:
The patent employs motion-adaptive filtering that dynamically adjusts the filtering strength based on detected vertical motion. When vertical motion is present, stronger filtering is applied to prevent artifacts; when motion is absent, minimal filtering is applied to preserve image quality and minimize information loss.
Solution Approach 2:
The patent changes the filtering parameters adaptively based on the vertical motion content of the video signal. The filter cutoff frequency and strength are adjusted in real-time to optimize the balance between artifact reduction and information preservation for different scene conditions.
3Object-generated harmful factors
If motion-adaptive filtering is used to reduce artifacts, then artifact reduction is improved, but processing complexity increases
Solution Approach 1:
The patent applies motion-adaptive filtering with different filtering strengths to different regions of the video signal based on local vertical motion characteristics. This allows artifact reduction to be applied selectively where needed while maintaining simplicity in regions where filtering is not required.
Data Source
AI summary
Methods and systems for pre-processing a progressive scan signal comprise: receiving by a processor thea progressive scan signal; detecting an amount of vertical motion present in the progressive scan signal; low pass filtering the progressive scan signal in a vertical domain as a function of the amount of vertical motion present to generate a pre-filtered progressive signal; and interlacing the pre-filtered progressive signal to generate an interlaced signal having a minimal amount of artifacts.