Display Camera Color Calibration via Test Pattern Feedback
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Solution Overview
Problem
Video conferencing systems face poor image quality due to the light emitted from display devices, which interferes with color reproduction, especially under varying illumination conditions, causing unwanted color hues in captured images.
Innovation Solution
A method and apparatus that display test patterns to a camera, allowing for the generation of a color transformation to adjust the camera's color balance, thereby compensating for the light emitted from the display device and improving color reproduction in video conferencing images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the display device emits light for image display during video conferencing, then the displayed image is visible to participants, but the emitted light causes color distortion in images captured by the camera
Solution Approach 1:
The system performs preliminary calibration by displaying test patterns and capturing reference images before actual video conferencing. This preliminary action characterizes the display's light emission properties and pre-computes color transformation matrices that will be applied during runtime to compensate for color distortion caused by display light.
Solution Approach 2:
The system changes color balance parameters dynamically based on ambient lighting conditions and display characteristics. By adjusting color transformation matrices according to measured display emission and ambient light levels, the system maintains accurate color reproduction despite varying illumination conditions during video conferencing.
2Adaptability or versatility
If the camera captures images under varying ambient illumination conditions, then the camera can adapt to different environments, but the color balance becomes inconsistent across different lighting scenarios
Solution Approach 1:
The system implements feedback by continuously monitoring ambient light conditions and display emission characteristics, then adjusting color balance parameters in real-time. The camera captures reference images under current lighting conditions, compares them against calibrated values, and applies appropriate color transformations to maintain consistent color reproduction across varying illumination scenarios.
Solution Approach 2:
The system performs preliminary characterization of both the display device and ambient lighting conditions to establish baseline color transformation parameters. These pre-computed transformations are then applied during video conferencing to maintain color consistency regardless of ambient illumination variations.
3Manufacturing precision
If the system performs color calibration using test patterns and reference images, then color reproduction accuracy is improved, but the complexity of the device increases
Solution Approach 1:
The system performs self-calibration by automatically capturing test patterns displayed on its own screen and using these to characterize its display's light emission properties. This self-service approach eliminates the need for external calibration equipment or complex manual procedures, achieving accurate color reproduction through automated reference image capture and transformation matrix computation.
Solution Approach 2:
The camera serves multiple functions: it captures both the test patterns for calibration and the actual video conferencing images. The same imaging sensor and processing pipeline are used for both calibration and operation, eliminating the need for separate dedicated calibration hardware and reducing overall system complexity.
Data Source
AI summary
A method including: outputting, for display on a display device, a plurality of test patterns; obtaining, from a camera, a plurality of test images of a subject exposed to the plurality of test patterns displayed on the display device; generating a first color transformation based on the plurality of test images; and adjusting a color balance of the camera based on the first color transformation.