Video Freeze Detection Circuit Using Segmented CRC Analysis
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Solution Overview
Problem
Existing vehicle display systems struggle to accurately detect frozen video signals due to noise interference in the transmission path, leading to incorrect detection of video freezing conditions.
Innovation Solution
A video signal processing device that divides the video signal into partial signals, detects changes between frames using CRC calculations, and generates a freeze detection signal based on the consistency of these changes over multiple frames, ensuring accurate detection even with noise present.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If CRC check values are used to detect video freezing, then processing load is reduced, but detection accuracy deteriorates due to noise affecting the hash values
Solution Approach 1:
The video signal is divided into multiple partial video signals (first to k-th partial video signals) for each frame. Instead of computing CRC on the entire video data, the system computes CRC separately on each segmented partial signal. This segmentation allows the system to maintain reduced processing load while improving noise tolerance, as noise affecting one partial signal can be compensated by the consistency checks across multiple segments and frames.
2Measurement precision
If video data is directly compared between frames, then detection accuracy is improved, but processing load increases significantly
Solution Approach 1:
The patent introduces CRC check values as intermediary representations of video data. Instead of directly comparing large video data blocks, the system computes compact CRC hash values that serve as mediators for comparison. The invention further segments the video data into partial signals before computing CRC, creating intermediate representations that are both compact and noise-resilient, thus reducing processing load while maintaining detection accuracy.
3Reliability
If noise enters the transmission path, then false positive detections increase, but the system needs to maintain high detection accuracy
Solution Approach 1:
The system employs a feedback mechanism where CRC check values from multiple partial video signals and multiple frames are compared and aggregated. The video sameness determination unit uses feedback from these multiple comparisons to determine whether video freezing has truly occurred. This feedback-based aggregation allows the system to distinguish between noise-induced variations and actual freezing conditions, maintaining high detection reliability and accuracy.
Data Source
AI summary
A video signal processing device includes: a video signal dividing unit configured to divide a video signal into first to k-th (k is an integer of 2 or greater) partial video signals for each frame; a video change detection unit configured to determine, for each of the first to k-th partial video signals, whether or not a video based on the partial video signals has changed between respective frames, and generate first to k-th video change detection signals representing the respective detection results; and a video sameness determination unit configured to generate a video sameness signal indicating that the video signal has not changed, if the number of video change detection signals that indicate the video has not changed, among the first to k-th video change detection signals, is greater than a prescribed number.