Video Output Checker for Vehicle Instrumentation Warning Verification
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Solution Overview
Problem
Existing video output checkers, particularly for LCD-TFT screens in vehicle instrumentation clusters, face challenges in accurately verifying the display of warning messages due to issues like dithering, noise, and partial obscuration, which can lead to false error messages when using checksum algorithms like CRC32.
Innovation Solution
A video output checker that compares each colour component of pixels in a selected area against a test range, sums deviations, and compares the error value against a threshold, allowing for a greater tolerance in colour variation and partial obscuration, thereby reducing false positives and improving accuracy in detecting correctly displayed warning messages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If checksum algorithms like CRC32 are used to verify display content, then detection precision is improved, but false error messages increase due to dithering, noise, and partial obscuration
Solution Approach 1:
The patent changes the verification parameter from exact checksum matching to tolerance-based range comparison. Instead of requiring precise pixel-to-pixel matching, the system defines acceptable value ranges for each pixel and checks whether displayed values fall within these ranges, thereby tolerating dithering and noise while maintaining verification effectiveness
Solution Approach 2:
The patent applies partial verification by focusing only on critical pixels that contain warning message information, rather than verifying every pixel in the display area. This selective approach reduces the impact of noise and dithering in non-critical areas while ensuring accurate detection of warning messages
2Difficulty of detecting and measuring
If external cameras or image sensors are employed to monitor the LCD-TFT screen, then display monitoring capability is improved, but device complexity and resource consumption increase
Solution Approach 1:
The patent integrates the display verification function directly into the existing display controller hardware, allowing the same hardware to perform both display rendering and content verification. This eliminates the need for separate external cameras or image sensors, reducing device complexity while maintaining monitoring capability
Solution Approach 2:
The display controller performs self-verification by comparing its own output signal against expected values before the signal reaches the LCD-TFT screen. This self-service approach eliminates the need for external monitoring devices and reduces processing overhead by verifying content at the source
3Measurement precision
If strict checksum verification is applied to ensure accurate warning message detection, then measurement precision is improved, but the system becomes overly sensitive to legitimate variations like dithering and partial obscuration
Solution Approach 1:
The patent transforms the verification parameter from exact value matching to range-based comparison. By defining minimum and maximum acceptable values for each pixel and checking whether displayed values fall within these ranges, the system maintains detection precision while adapting to legitimate variations caused by dithering, noise, and partial obscuration
Solution Approach 2:
The patent applies verification selectively to only those pixels that contain critical warning message information, using techniques like region of interest (ROI) definition and critical pixel identification. This partial verification approach reduces false positives from non-critical areas while maintaining high detection accuracy for actual warnings
Data Source
AI summary
A video output checker (23) is described. The video output checker is configured to receive incoming video data (20) for rendering an image on a display (17). The video data comprises pixel data which comprise, for each pixel (42), a set of color component values (57, 57 2, 57 3) for a given color model. The video output checker can be configured to compare each color component for a pixel in a selected area (24) of the image with a corresponding test range of values (5 1L, 5 1U, 5 2L, 5 2U, 5 3L, 5 3U) and, if a component value falls outside the range, to measure a deviation. The video 10 output checker can be configured to sum deviations for the selected area to provide an error value (58) for the selected area, and to compare the error value against a threshold number (59). Additionally or alternatively, the video output checker can be configured to determine whether each color component for a pixel in a selected area (24) of the image falls within a corresponding test range of values (5 1L, 5 1U, 5 2L, 5 2U, 1 5 3L, 5 3U) so as to determine whether the pixel is valid or invalid and to count the number (58) of valid or invalid pixels in the selected area. The video output checker is configured to compare the number of valid or invalid pixels against a threshold number (59).