Video Display Full Black Detection Circuit Resolution Change
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Solution Overview
Problem
Existing video display devices take a significant amount of time to determine whether the type and resolution of an input video signal has changed, leading to potential display of disturbed images during the transition.
Innovation Solution
Incorporating a full black detection circuit that detects a full black signal when the video signal changes and maintains this detection for a predetermined time, allowing the signal discriminating and monitoring circuit to quickly determine resolution changes by checking the frequency of the horizontal synchronizing signal in the next frame, and the scaler circuit to freeze the image until new settings are applied.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the video display device uses conventional signal discrimination methods to determine video signal type and resolution, then the device can accurately identify signal parameters, but the determination process takes a significant amount of time causing disturbed images during transition
Solution Approach 1:
The system performs preliminary actions by detecting full black signals and maintaining detection results for a predetermined time before making final determination. This preliminary detection phase identifies signal changes early, allowing the system to prepare for transition before the actual signal switch occurs, thereby reducing the time loss during signal determination.
Solution Approach 2:
The system implements feedback mechanisms where the signal discriminating and monitoring circuit continuously monitors video signals, compares them against stored patterns, and adjusts its determination based on feedback from full black detection. This feedback loop enables faster and more accurate signal change detection by iteratively refining the identification process.
2Loss of time
If the device quickly determines video signal changes without additional detection circuits, then the response time is reduced, but the reliability of signal change detection may be compromised
Solution Approach 1:
The system segments the signal detection process into distinct functional components: a full black detection circuit that identifies specific signal patterns, and a signal discriminating and monitoring circuit that performs comprehensive analysis. This segmentation allows each component to specialize in specific detection tasks, improving both speed and reliability by distributing the detection workload across dedicated circuits.
Solution Approach 2:
The full black detection circuit acts as an intermediary between the video signal input and the main signal discrimination process. It serves as a mediator that pre-processes the signal by identifying full black patterns, thereby preparing the signal for faster and more reliable analysis by the main discrimination circuit.
3Ease of operation
If the scaler circuit continuously processes video signals without freezing, then the display remains smooth, but disturbed images may appear during resolution transition
Solution Approach 1:
The system applies preliminary anti-action by detecting full black signals and maintaining detection results before actual signal changes occur. This preemptive detection allows the scaler circuit to prepare for upcoming resolution changes in advance, counteracting the potential for disturbed images before they can appear on the display.
Solution Approach 2:
The system implements beforehand cushioning by maintaining full black detection results for a predetermined time period. This cushioning period creates a buffer zone during signal transitions, allowing the scaler circuit to smoothly handle resolution changes without causing disturbed images, thereby protecting the display quality during the transition phase.
Data Source
AI summary
A signal discriminating and monitoring circuit provides a full black detection circuit which detects a full black signal input during the change of the video signal and holds the detection result of the full black signal only during the specified time period. When a full black video signal is detected in the full black detection circuit, the signal discriminating and monitoring circuit detects whether the resolution of the video signal input has changed by determining whether the frequency of the horizontal synchronization signal included in the video signal of the next frame to be input changed above a preset value. When a change in the resolution of the video signal is detected, the change detected signal indicates that the detection result is output. When a scalar circuit receives the change detected signal, the video display signal is output as a constant value in order to set the display video in the static state.