Black Stripe Detection for Keystone Correction in Projection Displays
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Solution Overview
Problem
Projection-type display devices face challenges in accurately executing keystone correction and video signal processing when black stripe regions are added to video signals, leading to potential distortion and increased device costs due to unnecessary bandwidth and memory usage.
Innovation Solution
A video signal processing device comprising a black stripe detector, keystone correction processor, and video signal processor that detects black stripe regions, performs keystone correction, and implements video signal processing in a specific order to correct trapezoidal distortions and improve image quality without increasing device costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the projection-type display device mounts a black stripe region detection function, keystone correction function, and video signal processing function, then the image quality of the display video is improved, but the device complexity and cost increase due to increased bandwidth and memory capacity requirements
Solution Approach 1:
The black stripe region detection function is executed before keystone correction processing. The detected black stripe region information is stored and then used by the keystone correction function to avoid unnecessary processing of black stripe areas, thereby reducing memory bandwidth requirements and device complexity while maintaining image quality improvement
Solution Approach 2:
The system applies different processing strategies to different regions of the video signal. By identifying black stripe regions and excluding them from certain processing operations, the system reduces overall computational load and memory requirements while maintaining high image quality for the effective video regions
2Device complexity
If the black stripe region detection function is executed after keystone correction processing, then the device complexity is reduced, but the measurement precision of black stripe region detection deteriorates
Solution Approach 1:
The black stripe region detection is performed before keystone correction processing alters the geometric structure of the video signal. This timing ensures that the detection function operates on the original, undistorted signal where black stripe regions have their standard characteristics, achieving high detection precision without requiring additional complex processing
3Productivity
If the video signal processing function is executed before keystone correction, then the processing efficiency is improved, but the manufacturing precision of the corrected video signal deteriorates
Solution Approach 1:
Keystone correction processing is executed as a preliminary step before video signal processing functions. This ensures that the geometric distortion is corrected first, providing an accurate spatial foundation for subsequent processing operations such as black stripe detection and video enhancement, thereby maintaining high manufacturing precision while achieving efficient processing through proper operation sequencing
Data Source
AI summary
A black stripe detector is configured to detect a black stripe region of an input video signal in which a part of an effective region is a black stripe region, and to generate black stripe information. A keystone correction processor is configured to implement keystone correction processing for the input video signal, and to generate a keystone-corrected video signal. A black stripe information corrector is configured to correct the black stripe information which indicates a corrected black stripe region owned by the keystone correction video signal, to corrected black stripe information based on keystone correction parameters when the keystone correction processor performs keystone correction processing for the input video signal. A video signal processor is configured to implement predetermined video signal processing for the keystone-corrected video signal by using the keystone-corrected video signal and the corrected black stripe information.